Square boat cruising catamaran

Been thinking about a getaway boat for a year long ICW cruise. A 35-40ft shoal draft cruising catamaran would fit the bill quite well for our growing family of four. New boat prices are absurd, and the used ones are not far behind. What say ye about adapting bolger-esque square-boat concepts to a mutil-hull? I'm thinking of Idaho or Wyoming like hulls (extended up to provide full headroom) with an enclosed bridgedeck. I've seen his Double Eagle design, but i'm looking for serious accomodations with 2 single and one double stateroom and a spacious saloon and galley. I've looked at Kurt Hughes and James Wharrams designs, but my thoughts lie somewhere between. Would 6ft square hulls be that much less efficient than vee or round hulls? Or maybe trapezoid hulls - 6ft on deck and 4ft on the h20 side? My simple math suggests a <20% increase in hull wetted surface. Am I missing someting here? Anyone know of stock designs that might be close?

 

I don't think it will make enough of a difference in speed for cruising. The problem will be in behavior. A flat bottom boat has a tendency to pound and it pitches more violently too. James Wharram's first catamaran had square sections. He cruised it from England to the Caribbean without any problems. I had a 34' Wharram and was very satisfied with the rough weather performance; speed was great too. The drawback was the lack of elbow room. Those hulls are quite narrow. All multihulls have reduced capacity compared to a monohull of the same length.
Have you considered a chine hull? It is a compromise between a square section and a Wharram type. The only way I can see to include the accomodations you want in a catamaran is to extend the length to 60'. I assume you are reffering to a sailing cat.

 

I agree with Gonzo, the flat bottoms tend to pound in rough water and there are some open stretches of water on the great loop where you may need to wait days or weeks for good enough weather to cross.

What you are describing sounds a lot like a Carri-Craft Catamaran. They are really a Catamaran houseboat, but the have the room you desire and the older ones are a great value. Here is an example http://www.marinesource.com/buyerslistings/detail.cfm?ListingNmb=6110006 .

Sail boats are inconvenient for the great loop. You need a tabernacle mast to get under the low bridges (19’ is the lowest). There are long sections where it is nearly impossible to sail, so you need the ability to motor for extended periods.

Regards;
Mike Schooley

 

I belong to another boat design group and some interesting things have been coming up lately in catamaran designs. One post was of a dory hull split down the middle with the straight part of the hull on the outside and the curved portion in the tunnel.
This got me to thinking along your lines: straight sided sharpies, but split down the middle instead of two hulls.
From information gained through Power Multihulls magazine, symmetrical hulls appear to be acceptable for sailing cats. If you're thinking of a power cat, though, asymmetrical hulls with nearly symmetrical bows, low deadrise and chines in the tunnel are more suitable.
What I'm trying to say is your idea appears to be valid whether you want to go sail or power, but you might have to modify your approach.
Good luck.

 

Square boat is a good idea!

If you are going to build or design a catamaran with bolger type hulls please inform your friend! It is a very fantastic idea!
Cesar
caesar1@rocketmail.com

 

In your place, I would look into Richard Woods' Gypsy. It is based on dory hulls, and is a proven design. Unfortunately, I can seem to access his web site today, so I can't give you a link.