Multihull Structure Thoughts

At the top of each column could have a heading such as " length*" an asterisk could be used with more description like you have done.

For example [length*] [page] [ hull*]



*description
column 1 - measurement are in feet *1 denotes general item.

column 3- proa ,trimaran, mono, cat, *g denotes general item .

I don't know if this helps


It's a pretty amazing reference thank you.

 

TTLF. Thank you for your input. R was for rigs but as the index developed over 6 weeks such classifications became harder. There are about 200 general entries and 1,150 boats mentioned (including some repeats). Result is I will work on cleaning up the index and update it occasionally as each new item in effect needs to rebuild the index if it is to keep its length integrity. Also there is a limited amount of space for attachments which has resulted in the need for at least 110 entries per page of attachment. This limits the amount of heading space that can be placed on a page. I ask the moderator to replace the new length index as it is on the first page and will work on a better version after Christmas.

 

Moderator. At your convenience can you please replace the existing index's on page one of multihull structure thoughts with the 9 pages of length index above. I will return after Christmas with more but life is getting in the way for a week.

 

Updated now.

 

It is a Bernard Veys design :
http://www.enthousiaste.com/blog/wp...gue-bateaux-bernard-veys-architecte-naval.pdf
https://www.youboat.com/fr/d/voilier/amateur/elfe-8-alu/323749
Silvestre Langevin was the designer of a quite similar cata in those days, the Edel cat 26 :
Les petits catamarans de croisière de moins de 9 mètres pour des navigations côtières https://mersetbateaux.com/petits-catamarans-croisiere/

 

Thanks, Dolfiman !

 

Not many details and one crummy photo, but it could be a sweetheart of a deal for someone looking to sail into the new year.

A quick search didn’t turn up this design having been discussed unless I missed it.

Looks to be well equipped and a swing wing. No mention of trailer.

Always been a fan of Newicks designs. If I didn’t already have my Seawing I’d be checking this one out.

newick trimaran


newick trimaran - boats - by owner - marine sale https://sandiego.craigslist.org/csd/boa/d/homer-newick-trimaran/7425221290.html

 

I had the smaller 23' version many years ago. Can't remember the name. Home built plywood. The accommodations are very cramped. Never seen an Argonautia in the flesh, I don't know that there are any here in Australia.

 

Earlier in December we were discussing the NZ catamaran built from 1/4 mold. I was cleaning up my HD today and happened on a video the seller pointed me at at the time. Looks like it was 2011 when it was for sale. Anyway it's still on youtube. As you can see the boat moves quite nicely. If I could have sensible broken it down and put it in a container I would have but from memory the beams were glassed in. I THINK the hulls were only 3' wide or something.

 

Hi,

I saw pictures of your Harryproa 50 on Rob Denney's website. Very good job ! I would be happy to read you about your experience !

 

Well, work continues on the Skoota 32. It is cold here tonight at minus 8F headed to minus 20F. I have a oil filled heater in the cabin. It always amazes me how much content oldmulti produces. I can't keep up with it, but now and then skim and catch up. Lately, I have gotten to that stage of the build where every extra weight has me nervous my boat is too heavy. It all started with engines and bracket at 122# extra each and I made the hulls 1.5" narrower than designed. Time will tell, but truth be told, I am a bit worried. Every single thing I think about these days is how I could have made her lighter. Smaller fillets, lighter, thinner plywood inside benches, thinner console; less glass here or there. Perhaps this is some prelaunch jitters, but boat weight can be scary for a prototype. We even have two mfd's, autopilot, two solar panels at 100# or more. I only installed two batteries this far and those are 63# each! My hulls are quite narrow (for high efficiency) and reserve does not creep up fast.

We will launch sometime in 2022. The marina on the Mississippi River in downtown Saint Paul. Minnesota opens May 15 at the earliest. If thinga turn out right; the boat is heading to the Gulf of Mexico as soon as 2023.

The main reason I am posting is because I'm not sure if we mentioned in this thread, but Richard's lovely Skoota 28 was destroyed by Hurricane Dorian at Marsh Harbour. The boat might have been salvageable, but there was no infrastructure there for timely repairs and the boat was a total loss afaik.

Anyhow, if anyone has any wise words for a nervous builder; I'm all ears. Last week, I calculated my 3/4" ply benchtops could be holed with 2" diameter holes and 20 of them would be a pound. I figure I can take out about 7 pounds out, but that isn't enough to be a notable delta. I made some of the kitchen cabinets from King Starboard with I genuinely dislike with great passion. Stuff is too heavy. The doors will be made with wood. I have even been dreaming about remaking my benches with 4mm okume and 10mm timber to save weight. Biggest problem is uncertainty..I'd like to come in around 9000 pounds, but really worried about ending up at 10,500 which is over by a couple inches...scary with outboards. The outboards are vmax sho 90s with long legs which are like 100# more each. Imagine needing to return brand new engines and falling back to the designer spec and selling the wife on that!

Anyhow, carry on old multi.

And don't mind the bedding compound in the picture; you can't remove the excess in these temps.

thanks for the load cell comments-let's move the content to another thread please for old multis wonderful work here

 

Fallguy; I’m not familiar with King Starboard so I googled it, Jesus wept. Bench tops motors etc. I think you have reason to be concerned. This is a common home builder problem.
Stay calm, don’t panic, hire some load cells and weigh the boat, put some numbers to it, until you do that your second guessing and speculating. Don’t guess, don’t think “she’ll be right”
Weigh the f…….g boat.

 

A load cell converts a force into electrical current by "flexing" a load sensitive material. In practice they make digital scales or things like load sensors on rigs or for a crane. The same principle can also be used to measure flex in structures.

 

Load cells are just electronic scales, you can get one for each corner and plug them in to a central unit to sum the weight. I’ve seen them used and seen them for hire but not done it myself. Just thought that would be the most convenient way to weigh the boat.

 

Fallguy. When I built my first cruising boat, I wanted it strong with things that I thought I would need. 2 things happened, I did not need half the stuff and the interior layout was partially rebuilt the with much lighter stuff after I understood what was really required when in a seaway. Building light is hard, staying light is harder and getting rid of those things you paid for but is really not required, is even harder. As Redrueben says weight the cat as is and talk to Mr Woods if you have a problem. I hope there is no problem.

Cyril. The C50 proa being built by Scandavian Proa is not finished yet. Other 50 foot older model Harryproa’s have been built and sailed and you can find reports on the web about them or ask Rob Denny directly, he will either direct you to owners of explain the latest versions versus the older models. EG Rudder structures are different and improved etc. I have only been onboard a 60 foot modified from a 50 foot Harryproa that could sail but the builders modifications needed refinements. If built well and to plan they can do as advertised.

On to today’s design. Designed by Gino Gandino Design the Journey 53 Long Range Catamaran Is a new design for OceanTrawler Yachts. These cruising power catamarans have excellent fuel economy and extended range, spacious living and on deck areas, and stability underway. The Journey 53 LRC is 53.3 x 18 foot and has a 46.000 lbs displacement fully loaded and 43,000 lbs at half full load. It is powered by 2 x Cummins QSB 6.7 419 HP engines. It carries a total of 2840 litres (752 gallons) of fuel over 4 tanks. It has a 14 -17 knots cruise speed with a 24 knots top speed. The draft is 3.5 foot at half load. The hull length to beam at the waterline is 13.9 to 1.

The wave piercing bow allows the boat go through the wave instead of riding up and then down over the wave. This particular hull design does not have the dynamic buoyancy that you find in most vessels, in other words it does not produce noticeable lift when running, hence keeping the boat flat and smooth through choppy conditions. This reduces stress on the vessel and the crew. This design also has the benefit of reducing the boat’s wave making resistance which means she goes through the water easier, equating to better fuel economy. There are twin keels that are cutaway aft to feed clean water to the props, help protect the running gear, and optimize tracking. Tunnels help to minimize draft and improve the drive angle of the engines

The accommodation has 3 queen berth cabins in the hulls with 2 full size bathrooms with fresh water toilets. There is also a pantry/work room for maintenance. The engines are in separate rooms allowing access for maintenance. The main bridge deck cabin has a large galley, navigation steering position and seating with a table for many crew. The cockpit also has fish cleaning sink. The outside steering position is a flybridge arrangement with a spiral staircase from the cockpit.

The structure has major components of the hull and deck built using a resin infusion process. Initial layers are vinylester resin followed by alternating layers of bi-axial, uni-direction stitched roving/mat and Taiwan Glass mat. Above the waterline, Corecell structural foam core material is used in the hull, as well as in the superstructure, to create a stiff structure, which is reinforced by longitudinal stringers and multiple transverse frames. The hull-to-deck joint is sealed with adhesive, stainless steel bolts, and an inner lamination of fiberglass. The deck and bulkheads are fiberglass and structural foam infused panels. Bulkheads stand off the inner hull skin with pyramid-shaped foam blocks, and are heavily glassed in place to help spread weight and torsional loads. Windows are tempered glass 12 mm all around, except for the sliding door, which is 9 mm thick.

The second Journey 54 power catamaran is the Pilot House model which was in response to client requests. Again it is a Gino Gandino Design and the Journey 54 PH is 54 x 25 foot with a displacement of 50,000 lbs (estimate). It is powered by twin Cummins QSB 6.7 with 425 HP each. The draft is 4 foot over the keels and rudders. The length to beam on the hulls is 12 to 1.

The accommodation again has 3 double berth cabins with ensuite toilets. The engines are in separate rooms allowing access for maintenance. The bridge deck cabin area is divided into 2 parts. The upper bridge deck area that has the navigation steering and seating area for viewing forward and entertainment and a lower area which has the galley and dinette arrangements. This is a spacious layout. There is a flybridge and cockpits areas as well. This is a cat that you can get away from your fellow passengers for some quiet time.

Both are good concepts and I suspect will continue the fuel efficient, long range concept. Jpegs give the idea.