Multihull Structure Thoughts

Minor Threat. Welcome to the thread. You will get many views on the rig question but if you are going to sail solo or short handed and not going to seriously race then my preference would be the biplane rig. It may be slightly more expensive to buy the components and install but it will be easier to live with whilst sailing. If you want more performance the wishbone rig could be better. When cruising, reasonable average speeds and ease of handling are more important than outright speed. Have fun and good luck on the build of a good cat.

 

Thanks, I'm also read the bi rig is very easy to sail. With some built-in safety included over a high performance rig.

I'm will go with that

 

The following catamaran is a cruiser racer that was built in 1998 by SN Composites inc. to a Sylvestre Langevin design. This is a open wingdeck design that provides hull accommodation and a large open cockpit.

The Tango 30 cat is 32 x 17.9 foot and displaces about 6000 lbs. The aluminum mast carries a mainsail, genoa 135%, jib 100% and a Screacher on a Profurl furler. There is an Asymmetrical spinnaker. Draft over boards 3.2 foot. Rudders suspended on stainless steel stocks. There are 2 Yamaha 9.9 ELHW 1998 gasoline outboards, "High thrust".

The accommodation has in one hull a seating area that converts to a double berth aft with a galley forward and a storage area in the bow. The other hull has a double berth aft and toilet wash area forward with a single berth in the bow. The cockpit is large with a very good fold down shelter over the cockpit area and a windshield forward. A sensible layout for short term cruising.

The cat’s build was: Balsa composite / CoreCell foam / fiberglass and epoxy resin with bulkheads / frames in plywood. There is aluminum crossbeams.

This is a nice cat that appears to be well built. The jpegs give the idea.

 

This is about a cruising cat that is almost a floating apartment internally for 4 people. We have done an item on this cat before on page 89 but the internal accommodation layout on the F40-XT needs comment.

The Delta F40-XT is 39.3 x 23.4 foot with a weight of 26,400 lbs. The carbon mast carries a 677 square foot mainsail, a 365 square foot furling genoa and a 700 square foot Code 0. There is no fore beam but a prodder for the forestay. The length to beam on the hulls is about 9 to 1. The draft is fixed keels of 4.2 foot. The engines are 2 Yanmar diesels, 27 HP, with sail drives.

Delta 40 cats have high prismatic hulls with full stern and moderately full bows designed by Giovanni Ceccarelli who also was the principal designer for two Italian America’s Cup campaigns, Lake Garda challenge boats and many production boats. The standard Delta 40 cat has the same shell as the F40-XT and are cats in the French style.

The accommodation in the XT version is basically a double berth cabin and ensuite toilet area covering an entire hull in both hulls. OK, 2 double berths in a 40 foot cat with wide spacious hulls. Now my concerns. A loose arm chair at a desk in a hull, open shelves without a door or covering in a bathroom area, cushioned headboards on beds etc are great in marinas but at sea in a storm they can cause chaos and at worst cause damage as things are thrown around. The we get to the main saloon which says the interior is more important than the cockpit.

The main saloon has the equivalent of house couch seating as its main feature. OK, but at sea good ergonomic seats are important as you again can be thrown around in a seaway, especially in rough conditions. The galley space is good but it again is based on a smooth water layout. You need to be able to brace yourself in a seaway when preparing a meal so you can use 2 hands while cooking etc. The navigation area is good. The sailing cockpit is on the starboard mid roof helming position and sail control area. Alright, but only 2 people could fit and control sail handing equipment etc.

The focus of this layout is to have a stylish interior on what I would regard as a daysailing cat that overnights at marinas or calm anchoring spots. I am not suggesting this cat could not cross oceans but I personally would need to make the cat more suitable for people to live in in rough weather.

The cats’ structure is not specified but Giovanni Ceccarelli and Deltra are experts in composite construction. I am confident they specified a foam e-glass build with biaxial and triaxle cloths, hopefully in vinylester resins.

We have a good cat here that are being built on a semi production basis but this specific F40-XT version does not suit me because the interior is more suited to smooth water sailing than rough water sailing. Unfortunately, I live in a world where 15 knots is a normal breeze and 25 knots is not unusual on a cruise somewhere. Sea comfort is important.

The jpegs give the idea.

 

The following is about an American yard StellarPM which has a series of all-aluminum power catamarans named StellarCAT. Stellar builds the semi-custom hulls in USA but has modular interiors which are constructed at the StellarPM factory in Zhuhai, China. Nice business model. Hulls are the easy end of build, it’s the fitouts that take the real time and often in this class of vessel a large amount of money.

The model we will focus on is the StellarCAT AL20-2 which is 67.5 x 32.2 foot of unknown displacement. The draft is 4 foot. The engine option 1 are 2 Volvo Penta D6-IPS 500 HP with a peak speed of 14 knots and a 12.5 knots cruise with a 3,600 nautical range. Option 2 is options is 4 Volvo Penta D6-IPS 800 HP with a peak speed of 30 knots and a 25 knots cruise with a 1,600 nautical range. The fuel tanks have 18,200 litres which means a fuel consumption of 5 litres/mile at 12.5 knots but rises to 11.4 litres/mile at 25 knots. Translation, a 300 mile 24 hour trip at 12.5 knots will use 1500 litres (395 gallons) of fuel.

The accommodation is good. With EG 3 owners’ cabins and 2 crew cabins all with private ensuites. The main saloon has seating, tables and a bar, forward of the main saloon is the owners cabin and ensuite which is luxurious. The galley is full size and downstairs in the port hull. The external decks and flybridge are vast having such items as a 4 person Jacuzzi, a full wet bar and grill area and the forward deck has a netted sunbed area.

The build is mainly aluminum as indicated by the jpegs but the Walnut wood furniture and leather or stone internals are manufactured in China and imported for installation.

This is the smallest size in the Stellar range of catamarans that complements Stellar’s monohull range of boats.

The jpegs give the idea.

 

Carbon 3 is a full racing trimaran designed by Nigel Iren for a Denmark group in 2011 and built by Tuco Marine group. This tri was designed to be a racer without compromise and has no accommodation worth mentioning. And this trimaran was (and still is) fast. Reason for the entry, it has just been purchased and imported into Australia for a refit for local Queensland racing. Some locals are getting nervous.

Carbon 3 is 40 x 32 foot with a 4,000 lbs weight. The 64 foot rotating carbon fibre wing mast carries a mainsail of 860 square foot, a jib of 377 square foot, a Code 0 of 1,070 square foot and a gennaker of 1,505 square foot. Enough sail power for 4,000 lbs of weight. The length to beam on the main hull is about 12 to 1 and on the floats about 18 to 1. The draft over the float based boards is 12.5 foot.

So, what does this mean for performance. Peak speeds of 32 knots, but far more impressive is achieving 27 knots of boat speed in 8 knots true wind speed. The tri has averaged over 14 knots in the 205 mile Danish Round Sealand Race. Yes, this is a seriously fast all round tri.

Mike Peberdy has brought the boat to Australia and is getting the rebuild done. He wants to compete in Hamilton island and the Brisbane to Gladstone race. In both cases if the weather is kind only 60 foot racing tris will be able to stay with him.

The build is pure carbon fibre foam epoxy cooked in an oven. The builder has over 200 boats experience and knew what was required to achieve a light strong boat.

The jpegs give the idea of a well designed and built racing tri.

 

Pssst, It's Nigel Irens.

 

Sometimes I need to be reminded that sailing is for fun and not all about the most efficient multihull to achieve a task. Here we have 4 guys who wanted an adventure crossing the Atlantic, so they spent 7 weeks building a quadamaran and set sail. Result 68 days, 2763 miles later (yes 40.6 miles/day) they had sailed from the Canaries islands to St. Maarten in the Caribbean.

So, what is this fine 7 week to build vessel. AnTiki is 40 x 18 foot of unknown weight. The 40 foot high telegraph pole mast carries a square sail of about 480 square foot. Each hull is about 2.5 foot in diameter meaning a length to beam of 16 to 1. There are 4 daggerboard planks used to help directional control. The rudders are 2 daggerboard planks on the stern. This is not an upwind sailing machine even though it has some capability of getting to about 75 degrees to the wind. This is basically a downwind raft that would peak at 5 or 6 knots with a reasonable breeze behind her.

The “cabin” is a 20 x 7 foot garden shed (yes almost brought off the shelf) fitted out with 2 bunks, a galley, seating area and stowage for all the spare gear.

The build of the raft is 4 x 40 foot long plastic waterpipes with 14 smaller diameter plastic water pipes acting as cross beams with 5 of the crossbeam water pipes were used for water storage. The cross beam pipes are web rachet strapped to the hulls. On the cross beams plywood is laid to form a deck then the tin garden shed is attached to the plywood. Do not use this form of construction if you want to sail in any form of rough weather.

For the adventurous and fun loving. The jpegs give the idea.

 

I tried a tiny 15’ loa pacific version of this with a sail with what might be called a ogival bi directional jib. When shunting this rig, it was unavoidable that, at some point, the sail would (will? ) be @ 90 degrees to the wind, even if floating on the wind like a kite. Knockdowns are inevitable. Other than that, you could steer with sail & weight, and she needed only one center ogival foil (Speer design) which was cool. No rudders too, which was even better. But anything over 12 k true wind was, um, difficult. A sail that will, in some way, luff, is a good thing. But even a dipping lug can be a handful during a shunt.

(Now, a sliding mast base on a longitudinal rail would seem to be excellent, but….)

(pics are of 2 different versions of related ideas, sorry, can’t find pics of the ogival jib version)

 

My similar adventures with the thing (ogival bidirectional jib, Bolger, AYRS, Biaxial (in my case)) on my first proa ACDC didn't have much trouble with shunts once I fashioned a sliding tack somewhat like a draftsman's parallel bar turned 90 degrees
(for a proa that's somewhat natural ;-)). But the circular section sail that switched luff and leech with every shunt was erratic, either drawing well or stalled miserably.
My current sail' a cambered panel staysail with rigid straight battens maintains a dedicated luff and leech and alternates windward/leeward sides of sail like a normal boat, seems to be a much better choice even early in development, and reefs much easier.

 

Sorry folks, no entry today, I have an electrician doing work on the place today.

 

In light of the AnTiki post above and OldMulti taking a day off, I thought I would post this video I quickly cut together from footage I took a weekend ago.

Anticipating her arrival, I had motored out of the Bay waiting to greet her with hopes of getting some footage with the sails up, but unfortunately she was already in tow.

Hanalei was her first stop as she embarks on a 7 month long island visiting voyage.

 

This tri Gauloises IV (also known as Roger Gallet) is a Dick Newick design and was built in 1979 by Walter Greene. The design is related to EG 3 Cheers and is a development of Newick’s Val 31 and Greene’s 35 foot Olympus Photo. Its racing history is good with EG 1st in class, 3rd overall in 1981 TWOSTAR. 4th place in 1982 Route de Rhum. Set a single-handed transatlantic record of 13 days 8 hrs in 1980.

Gauloises IV Is 45.3 x 32.8 foot with an initial 7400 lbs weight. The race measurer of the boat found it was actually 43.8 foot and weighed 8000 lbs. The mast is 53 foot high and carries 1075 square foot of sail upwind. The draft varies from 2.5 foot to 8 foot over the central hull daggerboard.

The interesting part of this boat is the build. The floats are listed as Polyester (single skin with stringers), the main hull is foam glass but the crossbeam structure is West system plywood, molded ply and timber. All these techniques were known and used on other Newick and Greene designs but most are either all ply or all composite construction.

This tri has lasted well but required an upgrade in 1982 when Walter Greene lengthen the tri to 45 foot, the daggerboard case was strengthened and the rudder was upgraded to a more modern shape.

The sailors of the tri all were happy with its performance and sea keeping qualities. The tri averaged over 200 miles/day doing a singlehanded Transatlantic run and could peak at over 20 knots with favorable conditions.

The accommodation is minimal but reasonable. @ single berths, small galley, seating and a portapotti toilet. The cockpit is at the pitch centre of the tri for maximum crew comfort whilst racing. All winches and sail handling gear is set up for single handed racing. The tri was still racing in the late 80’s early 90’s and doing OK but technology and design had moved on.

Gauloises IV sailed until 1997 where it is claimed was destroyed on Sable Island in Canada.

Again, a well designed tri done by Newick and Greene that was very successful for its time. The jpegs give the idea.

 

This design was a development of the original Three Cheers built that Tom Follet sailed n the 1972 OSTAR. Mike McMullan was lost with the boat in the 1976 OSTAR following the death of his wife while preparing the boat.
Versions of this boat were drawn up to about MK5, in both foam glass and wood. Some had the full wing and others were paired down to the aka fairings.

 

Got a bit of a "Twiggy" look with the arched beams.