Multihull Structure Thoughts

[oldmulti]

There have been 2 recent high profile accidents in the Farrier trimaran world. The first was an old F 27 that was competing in the Round the Island race in Britian that was a case of being hit by a gust during a race and capsized (a Gunboat 60 plus cat also capsized during the same event). The second more troubling event was the failure of a Corsair 880 in the Race to Alaska. This was a fresh from the factory new tri that had significant structural issues during the first week of the event. The Corsair was eventually a “write off” according to its owners.

The Corsair 880 is designed by François Perus, from Pérus Yacht Design has designed several trimarans for Corsair. The Corsair 880 is 28.7 x 22.25 foot and can be folded to 8.2 foot for trailering. The weight is 3,659 lbs. The sail area on the standard 40 foot carbon mast is 554 square foot and on the sports version, the 44 foot carbon mast carries 677 square foot. The “Sport” version has the taller carbon rig, laminate sails with high-aspect square-top main and sprit. The length to beam on the main hull at the waterline is 9.5 to 1. The float length to beam is 15 to 1 to 13 to 1 depending on how hard you are sailing. The draft is 5.25 foot with the daggerboard down and 1.25 foot with the board up. The rudder is a transom hung kickup. The hull, deck and amas are all vacuum infused with E-glass, a PVC closed-cell core and carbon-fiber reinforcements for added strength where it makes sense.

From here I will give you some quotes from the Farrier group. Draw your own conclusions.

I’m sorry guys, I didn’t make it clear. The quote is from Team Tres Equis Facebook group
Team Tres Equis | Facebook https://www.facebook.com/groups/538038325003081/?ref=sharehttps://www.facebook.com/groups/538038325003081/?ref%3Dshare&exp=8ce3&mibextid=S66gvF
the team sailed brand new Corsair 880 in R2AK 2023 and had to abandon the race due to the boat failing apart.

“The boat fell apart under normal conditions on its fifth day on the water and is not fixable. The transverse bulkhead cracked on the starboard side on day two which required a field repair before starting stage two. The rudder cassette cracked about 4.5 inches under no load. The areas around where the armas attach were moving and water started penetrating the hull on both port and starboard… this indicated a catastrophic failure was in the near future so we turned around. Of 5 total days on the water 10 hours were in 20-25kts. About an hour cumulative was closer to 30kts and the rest was less than 20 kts.”

Re: R2AK - Structural Failures - A Cause for Concern?
From: martyn adams Date: Thu, 06 Jul 2023 02:49:32 AEST

FWIW, this was not quite your typical day sail or your typical sailboat race. I don’t know just how severe the conditions were but do have a little experience in the area north and west of Campbell River and specifically Johnstone Strt.

I watched with interest the audio/video clips of the Round the Island race and compared it with what I have experienced locally and up north. Two things are noteworthy.

Wind and current interactions can be similar and many of us have probably sailed in the crank sea conditions that result. The short steep but predictable waves can be tiring after 30 minutes or an hour but they are a challenge and are a fun topic for the conversation of the evening. The boat has flexed, twisted and creaked and no harm done…maybe. How many times the always present structural weak link was approached we never know and rarely even think about. That clank as the boat shoulders past a piece of junk in the water, forgotten.

A big difference between Round The Island race and R2AK however is the way the wind is constantly twisted by the ever present valleys formed by the islands that make up the Strait north of Vancouver island. Five to six thousand foot mountains on one side and dozens if not hundreds of channels between the islands on the other, it is very different from the Strait of Juan de Fuca which is a pretty straight channel between two mountains and a 25+ mile wide sound between England and France. I am not belittling either, only offering the difference.

I found that the sailing can be very different given the same overall wind and current conditions, especially at the upper extremes. I have never been out for 20 or 30 hours of pounding in those conditions. Frankly, I don’t believe our boats were designed and built for that punishment.

In my opinion, it is not a question of structural deficiencies. It is more a question of putting the vessel in conditions beyond its design limits for a time necessary for every weakness to be explored. If that cumulative design limit was exceeded in the first hour or after 30 years, the structure doesn’t care. You only feel better if it’s the latter, maybe.

Oh, btw, you can exceed those design limits within six miles of port Townsend in the right conditions.

Cheers, Martyn Adams

Re: R2AK - Structural Failures - A Cause for Concern?

From: KEVIN GRICE Date: Thu, 06 Jul 2023 04:31:55 AEST

See the descriptions on what failed in Chad's note below from the Team Tres Equis facebook page. Although you should feel free to reach out to Chad the owner via email and see if he is willing to share more detail. We also should ask all the US Corsair dealers to be transparent in what they know of the status and investigation. In my personal experience, Corsair is not responsive unless pushed and then will go out of their way to deny responsibility - my former Pulse 600 with gel coat blisters and deck delamination are a prime example. I didn't hear anything - despite numerous letters and contact efforts until I involved the Boat US consumer affairs representative. The Corsair Factory Rep then made up a story that I had purchased a used boat that was kept on a mooring without bottom paint!, this despite the fact the boat was purchased new and was never stored in the water. $8000 latter I had a repaired boat and a lingering distrust of Corsair. If it was a US company I would have sued but pursuing litigation in Vietnam would not likely be worth the effort. Yes I did purchase another Corsair, but you can be sure I'm looking for any evidence of cracks/delam well within the 5 year hull warranty. I'm watching my rudder cassette in particular given the Tres Equis experience.

The boat fell apart under normal conditions on its fifth day on the water and is not fixable. The transverse bulkhead cracked on the starboard side on day two which required a field repair before starting stage two. The rudder cassette cracked about 4.5 inches under no load. The areas around where the armas attach were moving and water started penetrating the hull on both port and starboard… this indicated a catastrophic failure was in the near future so we turned around. Of 5 total days on the water 10 hours were in 20-25kts. About an hour cumulative was closer to 30kts and the rest was less than 20. My email is ctwilson@cwilsonlaw.com

Kevin C760 Icarus

Re: R2AK - Structural Failures - A Cause for Concern?
From: Jeff Date: Thu, 06 Jul 2023 13:32:00 AEST

Ouch... Older Boat. Ruf Duck is deeply wounded.

I think that the starboard ring frame/lower strut mount is a pretty well known spot to keep an eye on. Maybe the reason we did not break Ruf Duck at that location this year is that we already did it a few years back. We beefed it up and have not had any trouble since. Maybe some people will not get this analogy... but if you ever 4 wheeled seriously you know that you do not buy a Jeep off the showroom floor and expect to do serious rock crawling or run through the Rubicon Trail (dating myself... but this is prior to their "trail rated" system... and even at that you would probably do some stuff). You could run that stock unit through the mill.. and maybe you get lucky... but you typically do things to make your ride more capable before you go. Most F boats or Corsairs are just that... off the show room floor. The only F boat that I am aware of that was advertised as something of an off shore (ie stronger) boat was the F33 (feel free to point me to text that corrects me). Uber envelope pushers like Cheeky Monkey (While it was in BC I think) went so far as to completely fill the cutout to the V berth in order to strengthen this area.

I am not saying that there was not something wrong with the laminate that caused the issues being discussed. I saw the crack in Victoria... and sailed the same leg from PT. It was a mild day and nothing that should have caused an issue to a properly set up stock boat that had no prior issues.

I will say that if I saw this same problem developing... I probably would have bailed on the race. After all... I had been there the year before and had seen a few things...

Jeff

Team Ruf Duck

Corsair 880 or Dragonfly 28 for solo ocean passages? https://forums.sailinganarchy.com/threads/corsair-880-or-dragonfly-28-for-solo-ocean-passages.242165/

According to Francois Perus (880 designer) the 880 uses the same laminate schedule as Corsair’s other production models so presumably it would have a similar level of robustness, even if not intended to cross an ocean. The main thing I’d be concerned about with crossing an ocean with a production Corsair boat is the tendency seen in a few models for the forward bulkheads adjacent to the lower folding struts to delaminate from the main hull under heavier conditions. It can be fixed/reinforced by tabbing to the hull, but not in the middle of an ocean! Both the Corsair 880 and Dragonfly 28 have CE ratings of (B) for sailing within 200 NM of shore, so you might not be able to get insurance for either for crossing an ocean.

The question for me is the design limits for the Corsair 880. If it is rated to 200 miles offshore, good but that does not mean it is structurally designed to sail/race through EG 50 knot winds in big seas. Clearer messages in marketing of products would help. Reality is conditions may have been to much for the tri, the tri may have hit things, there may have been build issues or the design limits were reached. Further understanding from Corsair will help us understand.

First jpeg is F 27 in the Round Island Race, rest of the jpegs are of the Corsair 880. Page 181 of this thread does a fuller analysis of the Corsair 880.

 

[oldmulti]

An interesting way of having fun in a transportable package. If you have a small cruising multihull and need a tender that can also be turned into a fun sailing cat then this maybe your solution. The Happy Cat Hurricane is an inflatable day sailing cat that can also have a small outboard to act as a tender. The catamaran is 16.3 x 7.6 foot with a weight of 187 lbs. The maximum payload is 1320 lbs. The 20 foot carbon mast carries an 86 square foot mainsail, a 32 square foot jib and an optional 92 square foot gennaker. The motor can be a 6 HP outboard. The entire board cab be packed up into 4 bags. Both 6 x 1 x 1 foot, and 2.5 x 1.5 x 1 foot in size. The assembly time is about 40 minutes.

The hulls are 16.3 foot long by 1.75 foot in diameter with 2 internal chambers and is made from Continental Material1100 dtex EPDM-Kautschuk. The hull material is strong and glued together. There is a multiyear warranty on the cat. The hulls are pumped up to 4.3 PSI. The main cross beam and framing structure are aluminum as are the central rudder and centerboard under the wing deck. All major framing components slot together with tension cables crisscrossed beneath the trampolines provide additional stiffness in waves. The frame also serves as attachment points for the trampolines, which are clipped on rather than laced like most catamaran tramps.

According to tests the Happy Cat Hurricane can do speeds of over 16 knots and has good sailing characteristics. On e reporter said “The ability to tack it like a dinghy, is because of the centerboard and rudder are mounted in the best place possible. “What makes it steer so well is the rudder is so far aft, which gives you a nice turning moment between it and the centerboard.”” During Sailing’s 2022 Boat of the Year (which the happy Cat won in the day boat division) the reporter said: “There’s a great sensation of speed,” Powlison reports, especially with the 91-square-foot gennaker. “The Velocitek SpeedPuck that was on the boat was reading 10 to 11 knots regularly, and it wasn’t hard at all to tack or jibe either. The spinnaker clew is pretty high, and the boomless square-top mainsail makes it really easy to get across the boat.”

So, a fun boat that can be taken home in a car or stored below in a small cruiser. The jpegs give the idea.

 

[cavalier mk2]

Well they certainly got greedy with that Corsair bulkhead aperture. I'd have the top closed in and the dagger board trunk moved to port to allow more meat to starboard. Yes the table seating will suffer. I'd in fact consider bulkheads on the fore and aft ends of the trunk. If you are a racer and have one already, I'd close the bulkhead entirely and use the deck hatch. The comments by Jeff from Ruff Duck pretty much nail it, only sail stock in nice weather.
For a production boat with compromises for accomadation this is easy to achieve by going for hikes when it breezes up etc.... It can get rough in the PNW even without the logs.

 

[oldmulti]

A comment from the Farrier group about the Race to Alaska Corsair/Farrier tri’s for 2023. Again, draw your own conclusions.

1a. Re: R2AK - Structural Failures - A Cause for Concern? #r2ak #structuralfailure #buildquality #overloading

From: vladimir.eremeev@gmail.com Date: Fri, 07 Jul 2023 10:53:54 AEST

I can not say for every year but in 2023 out of 7 corsairs/farriers entered only three completed.

2023 - 5 Corsairs / 2 Farrier

F-24 MKII

F-24 MKII

F-27

F-27

Corsair 880 Sport

F-25C

Farrier F9R (Ruf Duck for a second bite at the apple)

Both F24s Finished. One expertly driven by a solo sailor to solo record time. Another one carefully driven by two person team, finishing many days later.

F9R Ruf Duck. Finished with some minor issues costing them a few days

rest of the boats were out with some quite serious, if not catastrophic failures.

f-27 team Trimorons hit a rock while escaping gale in Johnstone strait and while entering a protected anchorage. Instead of the daggerboard being snapped it went all the way into cabin fully destroying front and back of the daggerboard case and flooding the mainhull. While having the main hull flooded we learned that flotation compartments in the hull are not air tight and never been air tight by the way they are glued to the hull.

F27 team Dogsmile. Main bulkhead delaminated

Corsair 880 Main bulkhead disintegrated.

f25C transom bulkhead and rudder attachments cracked

So, the count of casualties is high. I also, in my 35 years of sailing, never seen more twisting and boat breaking conditions as I have seen in a gale in Johnstone strait. I’m not even mentioning floating logs everywhere.

 

[oldmulti]

Today we will discuss a tri’s development and history, tomorrow we will discuss the float evolution and why the shapes we see today may not be the fastest shape for a cruiser. This is about a range of JSYD tris from the late 1980’s to the early 1990’s. These tri’s start at 30 x 29 foot with an all-up displacement of 3500 lbs. The first one is Caledonia which was amateur built in foam glass and sailed by John Shuttleworth design assistant, Rod Stuart, in the 1988 C-Star which knocked over 6 days off the transatlantic record when winning class 6. Caledonia was then followed by Shockwave which was designed to win the 30ft Class in the 1989 Round Britain & Ireland Race. Shockwave was a development of the successful Caledonia. Built for John Fowler by Dave Irving in Plymouth in vacuum bagged polyester and E glass, with carbon reinforcing in the main hull and crossbeams. The first jpeg is of this generation of tri’s. These tris had a 10.5 to 1 main hull and 180% float volumes. The rigs had 46 foot masts carrying a 425 square foot mainsail, a 220 square foot foretriangle and a 330 square foot genoa. The daggerboards were deep in the mainhull.

Shockwave was faster than Caledonia being slightly lighter and with a bigger rig but both boats were fast. Shockwave with its headsail (a high aspect deck sweeping blade jib with no overlap), sheeted at 6 degrees on an athwartships track in combination with the large, fully battened mainsail gives an upwind speed of 11.5 knots in a Force 3 tacking through 75 degrees. (The sort of performance you might expect from a 75ft maxi monohull.)

Now we get to the next iteration of this design series, Nai’a. Nai’a was designed for Mike Reppy who had a 42 foot JSYD tri prior. He wanted a fast tri that could do a Transpac race then do an attempt on the USA to Japan record. A lot of research went into the development of Nai’a (which will be the subject of tomorrows article) which resulted in an 18% faster tri than Shockwave. The performance improvements were in the floats and rig. The dimensions etc will be done tomorrow.

The tri was launched in 1992 and Nai’a was very fast and easily overpowered. On her first race in summer 1992 she capsized running down the coast south of San Francisco, chasing Aotea, the 40’ trimaran and transpacific record-holder. Why a 30 x 29 foot tri has a lot of lateral stability versus a minimum of fore aft stability. In short you can push harder upwind than downwind. You can trip over the bows if you push hard downwind. Mike was pushing very hard. This is a problem with all “square” tri’s. It is the sailor’s responsibility to respect the tris characteristics. The designer pushes the limit at the request of the owner, but the sailor is responsible for the on water actions.

Mike response was to modify Nai’a. The former 30-footer was literally cut apart and lengthened, 2 feet in each ama and 6 more feet in the main hull. With other additions such as a carbon fiber boom and spinnaker pole and a deeper daggerboard, says Michael, "the results have been dramatic. The boat is much more stable and controllable." JSYD had also deigned a rudder on each float as both Caledonia and Shockwave had lifted their main hull rudder out of the water under hard downwind conditions.

With a more controllable tri, Mike wanted to sail to Japan and decided in 1997 to try and break the San Francisco to Japan record. I will quote Mike from here: “On day 30, we were well ahead of record time, with under 300 miles to go to the finish at Tokyo Bay. We had sailed through several low pressure systems, and had one more to go with winds due to pick up, but were running comfortably under full main and spinnaker in about 15-18 knots of wind. I felt confident, had my smaller sails laid out to change down to, and went below to rest. But I fell asleep for about an hour, and woke up feeling Nai’a had picked up speed in the freshening breeze. Just as I was coming up to get the spinnaker down, Nai’a surfed down a wave and stuffed her bow, pitch-poled and capsized.”

More on the research that lead to the 30 foot Nai’a and the reason it was a very fast 30 footer that had an upwind speed of around 13.5 knots and off the wind of 22.0 knots. The jpegs tell part of the story.

 

[oldmulti]

Today the research that led to Nai’as 18% speed gain over Shockwave. Nai’a is 30 x 28.5 foot with a weight of 2,400 lbs and an all up displacement of 3,700 lbs. The 49 foot Barlow wing mast built in glass, foam, and Carbon carries a 460 square foot boomless mainsail, a 267 square foot foretriangle, a 456 square foot genoa and a 1,160 square foot spinnaker. The main hull has an 11 to 1 length to beam. There is a deep daggerboard in the main hull and in the initial design a rudder on the main hull which ended up being rudders on the floats. The floats are 190% buoyancy. A lot of power on a laterally stable short boat.

John Shuttleworth wanted to improve the speed of Nai’a over his previous Shockwave design and looked at 2 areas. The rig, which was improved by a wing mast that was higher allowing a 25% increase in upwind sail area. The Boomless mainsail has a full width traveller on the rear beam allowing more sail adjustment options and reduced weight. Better sail cloths were also used. Next area of research was in the float design. Shockwave had already shown it could be overpowered in broad reaching, downwind conditions and john decided to investigate float shape to gain more speed and help minimise any pitch pole characteristics.

I will start quoting John from here: “My research indicated that there were 3 basic trends in outrigger shape currently on the racing scene. The first was the type I had developed from my early racers, like Brittany Ferries GB, and Great American. These had the centre of buoyancy well forward, and the stern tapered out to a point. In later developments, for instance in Caledonia and Shockwave, the stern had become more of a canoe shape, but was still very fine. The total displacement of the outrigger had gone up from around 150% for Brittany Ferries GB, to 190% in Shockwave.

The second shape was a cross between what Nick Bailey and Nigel Irens were using. Hulls with a transom stern, a reasonable amount of rocker in the hull profile, and displacement of 190%.

The third shape is the one the French favour. Virtually no rocker along the keel line, a very full transom, and at least 200% buoyancy.

Finally I chose a fourth shape. This was a thinner version of the Shockwave hull. I wanted to check whether a deeper thinner hull was better than a fatter shallower one.

So, we tank tested those 4 shapes, at a length to beam ratio, at mid displacement, of around 13.5 to 1. I chose that ratio because the Taylor's series of tank tests has already indicated that there is this is an optimum L/B ratio for long thin hulls. Also it matched the amount of outrigger immersion I wanted at mid displacement to keep the windward hull clear of the waves.

We tested each of the 4 hulls at three displacements, (i.e. at three different depths of immersion) and at 6, 12, and 18 knots. I also looked at the effect of trim on drag (i.e. how much the boat is slowed by bow up or bow down trim).

Previous tank testing had shown that the factors worth paying particular attention to are, length to beam ratio, wetted surface area, block coefficient, hull draft, length to draft ratio, and prismatic coefficient. (Block coefficient is the ratio of the hull volume to a volume equal to the maximum waterline beam x the maximum draft x the waterline length.) (Prismatic coefficient is the ratio of the hull volume to a volume equal to the maximum cross sectional area x the waterline length.)

When I analysed the data from the tank test, what I was looking for were the trends in the above factors. If life was simple, all the factors would be at an optimum in the fastest model. However the same hull was not always the fastest at each displacement, nor at each speed. As the hull was pressed deeper into the water different factors became more important in determining drag. To complicate matters further, it is possible to have the hull pressed down into the water through the full range of displacement at each speed.

I was amazed at the huge variation of performance in the models. The French shape, (full transom - no rocker,) had 37% more drag than the Caledonia shape at 40% displacements at 6 knots, and between 9 and 14% more drag at all displacements at 18 knots. At 12 knots the performance was the same as Caledonia at 80% displacement, increasing to 9% more drag at 120% displacement. This was a surprise. I knew that the hull would have more drag at low speeds because of the high wetted surface area, but because of the fashion in France to use the shape I had been seduced into thinking that it may be fast at high speeds and high displacements. This is definitely not so.

Nai’a hull shape was a compromise of the 4 float shapes that provided the best speed at each point of float immersion. But this may not work for a tri that sails on its float hull (60 foot racing tri’s) or a cruiser like a Neel tri that only uses a limited range of float immersion.

Nai’a was constructed using Carbon Fibre and PVC foam and epoxy, with integrated structural techniques and the hull weight was carefully controlled. The net effect is a strong, light displacement hull with a high long term fatigue life. The main hull shape had a flair above the waterline to provide more accommodation space but this tri is not a cruiser, it is a more comfortable racer which helps the crew over longer distances.

We again learn a lot from some serious research. A “trend” of fuller ended floats may not add the speed expected but may be done for other purposes such as to act as “catamaran” hull for a tri that fly’s its main hull a lot. A cruising tri may find a canoe stern fuller ended float of more value. In short trust your designer understands the floats required for the purpose of your tri.

The jpegs give an idea. As mentioned yesterday Nai’a meet it target of being faster than Shockwave, 18% faster around a course.

 

[oldmulti]

Electric Philosophy is a very interesting electric power catamaran. When it went on it first coastal cruise, it had no shore power connection capability. It did the entire cruise on solar power. This cat can genuinely go “off grid” for months at a time, all without an onboard generator. Electric Philosophy hull shell and internals were designed and built by Sam Devlin with the electrical systems mainly by the owners Ed and Eileen Pauley. Electric Philosophy is 41.8 x 15.25 foot over the hull (and 15.5 foot over the roof, which is required for the solar panels). The displacement is 26,000 lbs. The draft is about 3 foot over the rudders and propellers.

Now we get to the power and propulsion system. I will give the upgraded version with two equal size motors, first version had unequal motors. The minimum size of each propulsion bank was based on an average draw of about 5 kWh for both motors combined and a minimum travel time of about 30 hours (including an overnight passage), which pencilled out to 150 kWh (5 x 30), which meant each propulsion battery bank must have a capacity of 75 kWh. As it turned out, a slightly larger 80-kWh battery bank is a nice size if you plan to use 200-Ah lithium iron phosphate cells. The boat is home to 4 battery banks. Each hull has a house bank and a drive bank. Each house bank is composed of 16 x 100Ah Lithium batteries grouped together in parallel, and there are 8 of those groups in series making 24 volts. Each drive battery bank is made up of 8 x 200Ah cells grouped in parallel, and 16 of those groups in series to make 48 volts. They power matching 20-kW motors (equal to 26 HP) and three-blade props on each hull.

Of the 25 rooftop 380-watt panels (9,500 watts total) with 36V nominal output, 20 (about 7,600 watts) are used for propulsion (10 for each drive bank). An even number of panels was needed for each drive bank, because the 36-watt nominal output panels had to be paired in series of two to supply 72V for the two banks’ 48V solar charge controllers. We need 72V because the charging voltage for a nominal 48V lithium battery is about 55V, and we require a minimum of just over 60V to the charge controller to supply this charge voltage. On the other hand, the twin house banks could use single panels to supply 36V to their 24V solar charge controllers. The remaining five solar panels provide 1,900 watts x 5 hours = 9,500 Wh (about 10 kWh) per day for house loads, with three charging the starboard house bank and two the port-side bank. We then split the house load circuits to approximately 60% starboard and 40% port, which worked out well.

So what does this mean in performance terms. I quote a test: “Once we were off the dock in our benign autumn conditions, the boat was generating a fair amount of solar power, though not quite as much as we were using. At their normal cruising speed between 5.5 and 6 knots, the propulsion drives were using about 3kw each. Of that, the sun was putting in about 1.5kw and the batteries were providing the other 1.5kw. If we throttled up above 7 knots, the draw increased to 4.5kw from the batteries. This was October, though, and the seasonal position of the sun and the patchy clouds didn’t provide ideal solar generation opportunities. With full summer sun, they can generate as much as the drives require to go closer to 7 knots.” And the owners’ comment: “Our longest day trip so far is 82 nm at an average speed of more than 7 kts, taking advantage of favourable tides and wind. This is the reason our average speed over the first 3,000 nm is nearly 6 kts. Our top speed is about 8.5 kts in calm conditions, but at that speed the motors are drawing the max 40 kW total power, so it is not a sensible travel speed.”

Electric Philosophy’s interior is an open concept, with a berth aft, head and separate shower midship to starboard and port respectively, the galley and dining area forward from there, and the helm station at the bow. The boat has walkable side decks, a generous aft deck, and a small bow deck that is well elevated thanks to Devlin’s attractive rising sheer line. The cabin sole follows these lines, rising slightly underfoot as you walk from the galley to the helm. Visibility from the helm is excellent with large windows offering almost 360° views. Not including the drive motors, it covers energy-hungry items such as the electric galley, hydronic hot water and heating system, lighting, navigation, radio, AIS, autopilot, charging personal electronic devices, and infrequent but big house loads such as the anchor winch and crab pot puller. Our galley included a large electric refrigerator/freezer and an induction cooktop, as well as an electric water kettle, a toaster, and a convection microwave oven. Occasional loads would include charging batteries for the electric outboard and electric bikes.

The build is normal Sam Devlin (who has designed and built 100’s of ply boats), plywood and timber. The hulls are flat bottomed. Sam uses epoxy liberally and often uses taped seams. His vessels have a history of longevity and strength. Sam understands how to build a practical strong boat that will achieve its designed goal. His designs for home builders (mainly mono power and sail) are impressive as well.

This is an impressive power cat that has already cruised 3000 miles in the Pacific North West. Congratulations to the owners Ed and Eileen Pauley and Sam Devlin for a very good design and build. The jpegs give the idea.

 

[SolGato]

Nice to see a sensible “low tech” electric coastal cruiser design that is built around understanding the limitations if one is budget minded but wants to be able to cruise electric only without the need for exotic proprietary components making up the propulsive system.

And their approach to splitting the systems to create independent redundancy while allowing enough voltage overhead to allow the system to actually work in fair conditions makes a lot of sense.

The only critique I have is that a more efficient hull design and reduction in weight would probably make up for the imbalance in power consumption versus generation, allowing for more efficient cruising speeds and higher sustained top speeds, or the need for less powerful motors.

And the sooner panels put out enough voltage to wake the controllers, the sooner you start a daily charge cycle, so feeding your Chargers (MPPT) max voltage will help to ensure you take full advantage of the days sun to replenish the banks before you say get under way and start using most of the power you are harnessing while cruising, because the system will wake up and start working earlier and continue working later/longer before ending a cycle, so I appreciate this being pointed out as it is lost on some, even though they didn’t go far as to say so, other than pointing out that you need more voltage than a bank’s voltage to be able to move power into it. So many systems I see don’t work as well as they could because this concept is misunderstood.

Being able to track the sun would also help, and some boat designs have incorporated this feature, but another way to improve solar power generation to better balance input/output power is to use Bi-facial panels which give a nice boost in ideal solar conditions without the need for additional surface area. The extra boost a Bi-facial panel might generate mid day might be the difference between say a 4kn cruising speed and a 7kn.

In short, this boat works as designed and can be enjoyed the way a number of boaters actually use their boats.

It’s the electric go fast boats coming out that can only run for 1hr that I still just don’t get.

Electric cruisers like this, although still somewhat limited, just make a lot more sense to me I guess.

 

[Russell Brown]

The only critique I have is that a more efficient hull design and reduction in weight would probably make up for the imbalance in power consumption versus generation, allowing for more efficient cruising speeds and higher sustained top speeds, or the need for less powerful motors.

Well said. Looking at the wake is all it takes.

 

[oldmulti]

The Wing 100 is a design proposal from Royal Huisman and is a true sailing yacht and features exterior design and naval architecture by Dykstra Naval Architects with interior design by Mark Whiteley Design. The 330 x 45 foot mono with a displacement of over 1300 tons. The schooner rig has two 220 foot carbon fibre Rondal free standing wing masts with each mast carrying about 9200 square foot in the mainsail and wing mast with a jib of about 6000 square foot. Total sail area is over 30,000 square foot. No mention of the sail cloth material but it would be virtually bullet proof with a lot of carbon thread etc. The draft is unknown but would be 20 foot plus.

The engine power of this boat is hybrid. To assist there is a built-in hydro-generator can produce 200 kW under sail, while the 5,167 square feet of solar panels integrated into the mast can generate 250 kW. That means you can use clean, green energy to power the electric propulsion systems (and/or the hotel load) and spend less on fuel. In fact, Royal Huisman claims Wing 100 will save you roughly 225,000 liters of fuel per year compared to a similar-sized mega yacht. As for speed, she can reportedly reach more than 24 knots at full tilt under sail.

The sail control is all electric with capture line winches and a high degree of computerisation. The free standing wing masts are almost your throttle controls capable of depowering the rig quickly by mast rotation. Reefing is mainly controlled by roller furlers.

The accommodation is vast. The layout is designed for 12 guests, a nanny and 16 crew members. The living area is spread over three decks, from the flybridge to the lower deck, all connected by an elevator and stairs. Here you can enjoy outdoor dining and relaxation. Stairs just forward of the double helm station give access to the bridge deck, a half-deck between the main decks and the flybridge for good operational visibility. The main deck offers plenty of volume thanks to the long waterline and generous beam. The interior is sober, with custom spaces for each owner to arrange as they wish. There could be an owner's suite, a VIP suite, five guest cabins and a nanny cabin. Crew quarters are located forward. There are toys galore.

The build is at the limit of aluminium construction says Royal Huisman and anything larger will require a steel hull. The interior finishes are anything the owner wants.

The jpegs hint at the vessel. A very large boat more orientated to sailing than power. All I need is the spare $500 million US.

 

[myark]

I worked for Austal Ships as Fabricator and A grade aluminum welder in Western Australia manufacturing from start to finish the Queen Beatle multi hull structure ferry that is supplied to Japan.
The queen Beetle features four 16-cylinder Rolls-Royce MTU Series 1163-Mo4 engines, and the trimaran can reach speeds up to 37 knots.
The pictures show me welding all the stringers to the cross members of the engine bay, after welding all the stringers I started to weld the heavy plate bottom hull onto stringers in overhead position.
The You Tube Movie shows placing the top deck part of Queen Beatle on to the bottom deck.

 

[oldmulti]

A quick follow up on float shape for tri’s over time. During the early days when Dick Newick’s Olympus Photo, had banana-shaped floats, pinched in at the bow and stern with canoe shapes. Dick Newick was the leading multihull architect of the time, was directly inspired by Pacific pirogues and multihulls. The floats were shorter than the central hull and had little volume and shapes not really optimized for lift. This shape was replicated by EG Ian Farrier, JSYD etc.

Next phase was as designers were asked for more performance, designers tried more width and bigger floats but still with the fine ends and full mid bodies. These boats were faster but started to have some problems. They had central rudders which could lift out in board reaching conditions, they started to have more lateral stability than fore and aft stability. Again designers were asked for more controllable performance.

The response was to put more buoyancy in the float bows and longer floats up to the same length as the main hull. The keel lines were flattening out. Some of the designers put rudders on the floats which improved control, this became very popular very fast. Speeds again in racing tris increased.

The next phase was the understanding that trimarans could be built very wide, very light for there size and skippers were learning to sail the racing tri’s on basically a float with the other 2 hulls flying for periods of time. The design of the floats then changed into basically a catamaran type hull with full bows, a full stern and inbuilt rudders and daggerboards on the float. The keel lines of these floats are a lot flatter than the pot bellied shapes of Newick type floats. There were some C foils in floats to provide partial lift. These tris are the OMRA 60 type tri’s and some of the latest smaller later production tris.

The next phase in float development is still underway. The full foiling inshore and offshore racing tri’s. The full foiling tri’s have full length, very full ended floats with sterns but they are varying in total float volume. The thinner smaller volume floats are being considered as they are lighter and the stability is being mostly done by the lifting C foils or T foils on the main and rudders. This is evolving situation as lifting foil structures can break leaving the tri to sail on the hulls alone. Evolution is a good thing.

As was pointed out in the Nai’a article, a float shape depends on the purpose and proposed speed range it is going to sail in. Fine ended float shapes work in light airs at low to moderate speeds, very full ended transom shaped floats work at higher speeds on racing tri’s that sail on 1 hull occasionally. Float shapes on fully foiling tri’s are still evolving but are very flat fore and aft to encourage early foiling and “planning” when the foil starts to take over.

A few jpegs to show the evolution.

 

[oldmulti]

Allan Larkin wanted a light, strong, modern, and fast catamaran. He previously owned a 50 foot Schoinning catamaran Attitude, and he also ran a 70-foot motor yacht at the same time as a mother ship. Yes, he can afford what is just about to be launched. He went to Cure Marine in Queensland who have a very competent group of multihull builders with over a decade of experience to build his new 70 foot all epoxy infused carbon fast cruising catamaran. Top priorities were stability, as well as speed under both sail and power. The Naval Architecture and Engineering has been done by Stuart Bloomfield from Melbourne Australia who took over Lock Crowther sail design business.

The Cure 70 is 70 x 29.5 and weighs 31,300 lbs. The fractional rig carries a one piece 82 foot Lorima carbon fibre mast from France, who have also made the unitary forebeam and longeron (slotted components). The mast carries a 1743 square foot mainsail and a Gennaker, Screecher, Genoa, Performance Jib, Self-tacker, and storm jib with furling everything out front. The cat has an electric winch to deal with them and the sheets. The hulls length to beam are about 13 to 1. There are hull based daggerboards. The engines are twin 110hp Yanmars. There are bow and stern thrusters, which have added a little more weight, and trim elevators on the rudders to control running attitude. These are required to maintain a reasonable trim under power or sail.

Speaking of performance, the owner wanted a cat that under power could achieve 12-15 knots into a 25-knot Sou'easter (a prevailing wind on the east coast of Australia) and under sail achieve up to 30 knot boat speed peaks. Allan Larkin is a 7 knot type of guy. If the cat is not moving at 7 knots under sail on goes the engine. Allan thinks 200 mile days are normal cruising speed but wants a powerful enough sailing cat to achieve 200 miles plus miles/day under sail. This cat could top 400 miles/day under ideal conditions.

This cat is built to EU Certification standards which adds dollars and weight eg. the glass in the saloon windows added 500kg (about 600 lbs) on there own. The majority of the cats build is epoxy infused carbon over PVC foam. An interesting assistance to the build of mould frames etc was the commissioning of the new 23mtr (75 foot) x 5mtr (16.3 foot) 3D printer. Tomorrow I will show a jpeg of its work.

The accommodation is unknown but Allan Larkin said “We've set her up for short-handed sailing, which will suit just my wife and I for those offshore cruises, or we can load her up with a crew of eight if we choose." Allan also likes to go fishing with his mates which resulted in a genset and 1.7kW of solar panels. Why, because the cat has 6 custom-made fridges and freezers (total 1000 litres) plus air-con to provide for. This cat also has an inverter for 240 volt power.

Result is a very impressive modern fast cruising cat that could give a good account of itself on a race course. Lets hope we see the finished result on the water soon. The jpegs give the idea.

 

[oldmulti]

The Cure 55 catamaran production project from Cure Marine was designed by Paul Bury Principal Naval Architect. The Cure 55 project was conceived to be a true sailors cruising catamaran able to be handled shorthanded. The Cure 55 is 58.3 foot length over hull and prodder with 54.5 x 28.5 foot hull shell. The light displacement is 20,095 lbs with a maximum displacement of 27,370 lbs. The 76 foot Hall carbon spar has a mainsail of 1,173 square foot, a self-tacking jib of 592 square foot and a gennaker of 2,110 square foot. There are Profurl furlers for the staysail, jib, and Code Zero. Dyform rigging is standard, and the running rigging is Dyneema core with Technora cases for heat and wear. The hull length to beam is 12.2 to 1. The draft ranges from 4.3 foot to 7.9 foot when the daggerboards are down. The underwing clearance is 3.3 foot. There are twin 57hp Yanmar saildrives with Gory three-bladed folding screws.

The standard layout has an owner’s hull to starboard incorporating a large ensuite. To port, there is a spacious aft guest cabin and a forward cabin with configurable options for an additional double berth, bunks with office space or a combination or workshop/storage space. The port hull also houses separate toilet and shower compartments. In designing the saloon, they provided seating for 8 around the port-side dining table with a large c-shaped galley with meal preparation using all electric appliances – No Gas. There is a standard watermaker. There is also a dedicated forward facing navigation area. The cockpit has large glass doors to the saloon. The Cure 55 has electric halyard, mainsheet winches standard with electric sheet winches etc. Also there is an enclosed loop “Flatliner” electric traveller system.

When it comes to the all electric facilities in the cat there is a 13 kWh Victron electrical system with 3 kW solar panels and associated system. The LiFePO4 batteries are in the tech-pit, right near the mast bulkhead, and the Cure 55 is a 48V boat with an optional single bow thruster. To quote the builder "We are running 240V for our induction cooktop, and oven via the inverter. This means we don't have to have any gas on board. Also, 48V creates a lot of efficiency. We can then run 48V winches, and a 48V windlass. Then there's the wiring. There is a huge difference between 12 and 48V and we save an incredible 250kg, just in the wiring alone!"

The construction is mainly epoxy resin infused carbon fibre throughout. The design from the very start was aimed at performance and ease of production build. To quote Cure Marine “Production of the Cure 55 catamaran has its foundations in the Designed For Manufacture principal and is underpinned and supported by some of the latest technology currently in use in global boatbuilding.” Cure Marine is at the forefront of composites design and manufacturing. They utilise an array of in house, state of the art automated machinery. Including robotic equipment, CNC Machines, laminate cutters and one of the largest 3D Printers in the southern hemisphere. To quote the builders “Did we mention displacement? Unfortunately, I just can't accept, or it probably would've bugged me fairly heavily, if I had ended up with a 50 odd foot cat that was in 13, 14, 15 metric tonne lightship range. I know that that is not a high-performance boat. I've built 52-foot high performance sailing cats that have come in at six and a half tons, and 60-footers at 10 and 11 tons. That's the standard that I was going to stick to."

What you have is a very high performance global cruiser. The first 3 have been ordered and will be launched in 23/24. Price about $2.6 million Australian (about $1.8 million US). The jpegs give the idea.

 

[oldmulti]

This is a short one about an affordable day sailing solar powered “motor sailor” trimaran built by Carbon Wacker (yes this is a real company). The E-Trimaran “Sunavio 1” is 14.75 x 6.56 foot with a weight of 72 lbs and a loading capacity of 448 lbs. The 9 foot carbon mast carries a 15 square foot mainsail. The floats are 6.5 x 1 foot. The mainhull is a canoe that is 2 foot wide giving a length to beam ratio of about 7 to 1 depending on load. Draft is minimal over the kickup rudder.

The power is provided by flexible solar panels on the decks which feed to 2 to 4 amp hour batteries. The 240 watt electric motor will drive the tri at 2 to 3 knots for a couple of hours. The auxiliary motor is a paddle or the small sailing rig. The tri can be ordered with or without the electric power system.

The boat is small and light enough to be left assembled for transport but can be disassembled.

The build is 100% carbon fibre epoxy with limited foam used. The curve shapes provide most of the stiffness.

This is a pure fun machine for a person who likes to potter around lakes or rivers. The jpegs give the idea of an excellent simple motor sailor for us older folks