Trimaran motorboat / stabilized monohull

Some pics of my 10m proto and drawing of the futur 12m.
On the proto :
The center hull is 80 cm wide, the amas are 20 cm wide.
The hull is 500kg in plywood/fiberglass.
The 60hp outboard make her going 22 knots woot / 17/18 cruise.

Does somebody made something similar to share numbers with me ?

Sorry for my bad English, I am a french frog!

 

Very jealous of your beach!!!

How much does she weight?

 

Hi Eric, welcome aboard

Quite a stylish thing, ain't she? (And I, too, am jealous of your beach )

Rick Willoughby (member on here) has been tossing around some variations of a "faux-tri" concept with some similarities to your hull. And on the larger side, one of the U.S. Navy's new Littoral Combat Ships also uses a similar tri-hull configuration.

 

Pas mal. C'est en bois?

 

Interesting design ! If you have more pictures it would be nice to see more of it.

The rest of you should note that Eric is a very clever person - note the fishing rods on his boat

 

thanks !

more pics of the construction on http://cinqiles.blog.fr/
more pics of our beach on the same link !

 

Figures?

10 m wl, 22 knots with 60 hp?
Can't be correct!
What total weight?
What prop?



js

www.sassdesign.net

 

Eric's hull dimensions and general below-water shapes are pretty close to those of a tri I'm working on now, although his is 2 m longer on the main hull waterline. If his bare hull is 500 kg, I would expect maybe a hair over a tonne (say 1000-1200 kg) with motor, equipment, fuel and a couple of people. (Eric- can you confirm your actual weights?) From my own calculations, 20 knots or so for a tri this size on 60 hp is not at all unreasonable.

 

Weight empty / no motor 500kg

60hp 2 stroke yamaha 102kg
Varta 55Amp 15kg ?
fuel 100 kg
hydrolic pump cylender and auto pilot 10/12kg
aluminium anchor and chain 15kg
extras 100kg

TOTAL : 850kg empty

22 knots wot is with 2 frogs 70kg and fishing gears for a total of aprox 1000kg
Cruising at 4000 rpm with 17"pitch prop give 17/18 knots depend on waves.

Cruising at 4000 rpm with 7 people and camping gear for a total of aprox 1600kg give 15/16 knots

I should try a 15" prop but can't find one !

 

That puts it around 60hp/tonne

Looking at my chart of old boats and sea trial data, that gives around Tq of roughly 4....this equates to 22 knots...so yes, stacks up.

With 7 froggies....(and their cheese, wine and bread too?? )...roughly 17~18knots..so again, not bad, stacks up with other trials data of this "type" and "size".

 

Great looks, and I bet she's a nice dry ride in waves.

Alan

 

Fantastic Eric!
I too would be jealous of your beach...if I didn't have access to similar ones myself
The boat is somewhat reminiscent of "White Rabbit" a superyacht built here in Tassie... if on a slightly more...err... practical scale
Please - more pics - particularly of the interior - I'm interested to see just how much space you managed to fit into (onto) such a narrow hullform.
There are a number of people (myself included) who are working on variations to the stabilised mono theme. Your's is a fine example - congratulations!

 

Hi Eric,

Nice looking boat. I was wondering about forward visibility though. How are you ensuring that?

I am currently designing a trimaran myself. A lot smaller than yours.

LOA: 5.90 m
Beam: 1.95 m
Draft: 0.40 m
Power: 15 - 20 HP

She'll be heavy though (about 1000 Kgs fully loaded), because I am designing her to be built from steel. I expect to get about 10 Kn @WOT with a 15 HP.

 

Eric i have just looked at your website and cannot find any pics of your boat on the water other than the 2 photoshop pics of the boat on the "beach" am i missing something?

Your build pics are great - and if you were able to go from wooden hulls (April 2009 entries) to the water in 6 months you did remarkably well

Your design concept is very interesting but it would be nice to see pics or video of the "tri" underway :?:

 

Thank's all !!

Martin, I think that lightweight is the key for economie ! "tri hull" structural shapes are easy to make very strong, much stronger than a clasic monohull. Make a balsa model of your boat and try to twist it !! You will see how strong it is ! I wouldn't go for steel.

Manie, I will try to catch pics and video of the "tri" underway.