Mini Dashew FPB

Originally Posted by srimes

Are catamarans more comfortable for a given length? What would you consider the minimum comfortable size for crossing oceans in a cat? Just curious.

Minimum to feel comfortable is a very broad range, because each individual has a different way to cope with motion and acceleration. But this type of vessel has some limits for seakeeping imposed by the hull design.
If the wave period is twice the spacing of the hulls, then the natural frequency in roll creates a resonant condition and extreme motions. Further, the cross structure is vulnerable to slamming if the wave heights are large enough. Finally, due to the relatively short hull length for the displacement, catamarans can experience significant pitch motions.

Hope that helps a bit.

Richard

[CatBuilder]

I would again agree with Apex1, but might add a few comments as well...

When the wave period is twice the hull spacing, the technique on a catamaran is to get off that point of sail. It is a very uncomfortable ride. It will thrash you all around. Even a very small change in course will move those waves from directly abeam to slightly aft, which allows the length of the cat to soak them up and stops this motion. Sometimes, you can't avoid this problem because the smaller waves may come from your beam while the larger from your stern. Then, you have a catamaran limitation to live with. I was just talking about in another thread.

Slamming of the bridgedeck is another thing that can be avoided by technique. The cause of bridgedeck slamming is either sharp waves coming up between the hulls, or more commonly, going to windward and pushing your hulls into (and under) very steep waves. If the hulls have enough buoyancy, they will push the rest of the boat up over the chop. So, the slamming is not only a function of the cat's bridgedeck height, but also a function of the displacement available as the boat is shoved underwater by momentum. If your hulls carry enough reserve buoyancy, they will keep above the water and keep the bridgedeck clear. This is one of the main arguments for a lighter catamaran being a better catamaran. They don't plow through the head seas, they pop up and over.

Catamarans, as Richard said, experience significant pitch. There is no seamanship fix to this one, as far as I know. The only fix I'm aware of is to have a long waterline for a given "size" catamaran. Catamarans also tend to jump from hull to hull with a very quick motion. These are simply motions you either get used to (like a monohull rolling or heeling), or motions that do not work for you. You must decide for yourself if these motions are acceptable. I like these motions more than my wife does, for instance. She prefers the monohull motion, but prefers everything else about the catamaran, so we stayed with catamarans. I got more seasick and annoyed with the motion of our old monohulls. Rolling at anchor at night was the dealbreaker for me, as a permanent monohull liveaboard. I had many a sleepless night and I couldn't deal with it anymore.

Lastly, to directly answer the question, it is my opinion that a 37' cat would be about the minimum I would personally feel comfortable with crossing oceans.

[dskira]

The more I look the more I don't see what the Dashew did as amazing.
They will spend the same amount of money with a boat twice as wide, far more comfortable and nice looking.
With a separate pilothouse
Dixon Kemp, Lursen, Sander Row, Abeking and Rasmunsen, DeVries and that the only few did this kind of hull for a century. And beautiful.
Why copying something that was already copied, big, small or medium size.
I think in my eye the one who approach the most the efficient hull with elegance is Tad with is light passage-maker serie.
I know it is one of our contention with Will, we disagree on this one. I hope he forgive me
It is only my two cents
Daniel

[WestVanHan]

Renko for a wheelchair handy boat,coastal cruiser type take a look at the Bluewater Coastal Cruisers.

Living is all on one level with rear master's stateroom-long,skinny,can go fast or cruise economically at 9 knots.
Huge deck,tons of storage.

Keeping an eye on the weather,they've done the Caribbean.

Stumble owns a 58'

As usual yachtworld will give you an idea,and very reasonably priced and gas versions are dirt cheap...

[renko]

Originally Posted by Tad

Most of the interior in a traditional raised pilothouse trawler yacht would be inaccessible to someone in a wheelchair. Therefor the conversion of something like this http://www.yachtworld.com/core/listi..._id=74591&url= starts to make sense...

Sell the 600 HP Lugger and the 2:1 gear and buy a new John Deere of 250-300 HP to turn the same diameter prop with a bigger reduction. You could build a huge cabin over the work deck and have almost all accommodation on one level, with perhaps a short ramp up to the helm area. Could be nice.....

my thoughts exactly. Keeps the aesthetics we like, and good hulls can be had for cheap. I am reasonably competent with woodworking, so building the interior is something I can do to save costs, conceivably 1/20th of the FPB.

With the gear reduction and engine swap - what sort of prospects are there for mileage?

[renko]

something like this sparks some ideas:

http://www.cruisingclub.org/pdfs/bws_foxy_lady.pdf

[goodwilltoall]

Greetings,

The mini FPB done by kiwifinn in the gallery is the best yet.

Peace.