Affordable 9m Catamaran

Hi All,

I had an idea to take as a base/inspiration and old successful catamaran, designed and fabricated in the UK in the 80s, (which is out of production by now), but still around and develop a new modern version, and if successful put in production.

Based on old photos/videos and info i've drawn the form plans and done some calculation of the old model (non of the old drawing/calculations survived, or can be found).

Next stage, will be to modify/model and improve the performance of the hull.

Or should i start from scratch? forget about the old cat?

 

Why did it fail?

 

As far as I'm aware could be the following reasons:
1. It become very expensive to be fabricate in UK.
2. Solid Fiberglas hull 8~10mm, very heavy, so not very great performance (4 tone weight at 9m x 4.2m beam)
3. CATALAC 9M more info here: Catalac catamarans - Wikipedia https://en.wikipedia.org/wiki/Catalac_catamarans

 

In practice, it is a matter of starting from scratch because, as in many other cases, you start with the b ody lines plan of a similar boat and start to modify things until you get the boat that is closest to your SOR. Of course, in the case of an old design (more than 30 years), it is very likely that the scantlings are oversized, so it would be best to calculate them again. After that, all the weights and their CoGs must be recalculated and the extent to which the old fairing works or does not serve the new conditions must be checked. Perhaps the new arrangement of transverse bulkheads forces the position and spacing of the frames to change somewhat, and so on ....

 

I can tell you as a builder of a custom catamaran the part that kills me is finishing. Endless hours and sheets of sandpaper.

A production boat needs finishing shortcuts. Moulds, first.

 

Welcome to the Forum Xpert.

Catalacs were very popular and successful in their day because they appealed to families then as one of the best 'small' cruising catamarans around.
I remember seeing them at Southampton Boat Shows in the 80's - Tom Lack and his wife were very good at PR and sales, and they achieved a huge following.

However everybody has moved on since then.
Hull design has moved on as well - compare the shape of a Catalac hull to any 'modern' cruising catamaran.
They are very different.
Generally speaking, the modern ones are beamier, have more room, are more ergonomic, sail faster, and are more comfortable.
Yet you will still have to charge the same for a modern day Catalac as for a modern day Woods, Fountaine Pajot et al - and which type will be more appealing to a family today?
I think you would have to start from scratch really - but I see that you have drawn some plans. Would you be happy to share these with us please?

 

I rather like the sound of matt 2-pack PU. It is available, and no doubt hides the proverbial "multitude of sins" !

 

You could use a version of this trimaran foiler 3 Devils' main hull to make a catamaran - just joking: 2 Devils? Accommodation is squatting below decks.

 

Yes the hull design of now and then is very different (also the software and material availability - planing to go for carbon with honeycomb core),
but at the same time i don't see anything wrong with the "V"shape hull design it has pros and cons and always can be improved.
I really like the all set up and compactness of Catalac 9, can say is a smart design and was using many futures of the time,
I don't try to build a performance catamaran like Outremer or HH, but more like a family weekend or coastal cruising catamaran,
BTW there is no modern entry level 9m catamarans (except SmartCat) plus is more like a modern cat just scaled down.

Ultimate goal of my project would be:
1. Smart and compact 9m x 4.5m (intent for family coastal and weekend cruising)
2. Use of Solar Power (something similar to silence-yacht)
3. Electrical Propulsion (something similar GreenStar marine)
4. Wing Sail.

Everything comes to price, Yes everybody want a big catamaran, but not many can afford it as a used one start from at least 200k,
plus it comes with the age related issues/problems etc.. maintenance of a used cat after 10 years is very high.

Have attached some Catalac 9 model screenshots and design analyses if somebody is interested.

 

Yes, a good mould + infusion and moving away from fiberglass to carbon is the way to go,
I've done some experimentation and testing of performance for carbon combined with rigid honeycomb vs fiberglass.

Attached some picture of the same in fiberglass and carbon fiber (two layers 300gms + 15mm honeycomb + two layers 300gsm)
results of the same size samples 90gr vs 120gr also both samples are very rigid and stiff

 

Yes, i'm using the old model as inspiration for shape general sizes and arrangements, but the new cat will have to be all recalculated and modernized.

 

Yes, trimarans are the F1 of the ocean, (Speed and Power like Clarkson say) but when it comes to cruising and comfort they are very limited and very expensive,
a good example will be DragonFly 32, everybody like the Dragonfly 32 performance, but not many can afford it at 350k

 

I knew the Lacks well, and also the designer they used as he was at college with me. There's a lot I could say, but to save time. Start from scratch. Don't reinvent the Catalac. You won't sell any, especially as you can buy a used one for GBP12,000 upwards and new will be over 100,000

My 30ft Symphony catamaran would be a suitable base to start from. Built as a production boat in the 90's but would need updating. Even so most people don't make money on production boats under about 45ft these days

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

I don't have any intention to reinvent the Catalac is just as a model of inspiration for shape general sizes and arrangements,
but yes i'm looking at all the old catamarans bellow the 30ft. There are just some futures which i like in all of them:
eg, solid front deck / no trampoline; beds on the main deck not in the hulls;

 

You still have to give the project a lot of thought, as you undoubtedly already know. For example, considering the shapes of the ship, it is possible to think that the draft will be large, the air gap small and, therefore, the superstructure, which must also accommodate the beds, will have to be very high, which can be an inconvenience.
In addition to the 3D models that are very nice but at the moment do not say much, I would draw a General Arrangement plan, to verify that each thing has a place on the ship and that this place is sufficient for each thing.