# How much boat?

Discussion in 'Boat Design' started by creosote, Dec 26, 2010.

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### creosoteJunior Member

I've been reading and browzing through your forums for days, now I finally worked myself up to a question? How much boat can you put in 40 ft X 8ft X13ft?

My interest in boats was sparked by BBC's Top Gear and their crazy amphibious cat stunts. From my reading, I've learned that long and deep hulls are "better" than shorter ones.

So if you were given the volume of a motorhome to work inside of, what kind of boat/amphibious vehicle could you have?

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### cthippoSenior Member

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### gonzoSenior Member

Long and narrow is not better than short. You need to take the whole design into consideration. Seems like you are answering your own question: you can put a boat that fits in the space available. Motorhomes have different parameters than boats. A boat with the equivalent volume will be longer and wider.

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### creosoteJunior Member

Thank you cthippo, I never thought to look into narrow boats. I suppose that I should have been more clear in my first post that the beam can not be more than 8.5 feet, which is the typical maximum width of road vehicles.

I'd like to add another thought to the mix: Class A motorhomes have about a 400 to 450 hp engine. What boat type would best make use of 450 hp, considering 40 length and 8 ft beam?

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### cthippoSenior Member

That is a LOT of HP for a 40' boat.

I suppose you could use that with a planing hull though.

Keep in mind the relative velocities involved. A motorhome needs to be able to do 70 mph on the freeway; for most boats 20-30 mph is just fine. Most 40 footers seem to be in the < 200 HP range.

Someone had a picture of an amphibious motorhome recently, I'll have to see if I can find it.

This thread went into this topic in some depth...

http://www.boatdesign.net/forums/bo...erable-power-cruiser-looking-ideas-34652.html

6. ### CatBuilderPrevious Member

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### creosoteJunior Member

I've seen pics of the floating rv, and it looks like fun for a weekend on a lake. But will that rv take to the open seas?

My goal is to have a long distance cruiser for a land/sea around the world trip. Since I'm not patient enough for sailing, I've tried to glean as much infomation abot fast/express cruisers/trawlers/trowlers.

Thank you for the "boat in a box" photo ( can I get that at IKEA?). It helps me to see these boats out of the water and compared to something I can relate to.

I've also found stories about the "Half Safe" an amphibious jeep that took 8 years to go around the world; I would like to go faster than that.

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### cthippoSenior Member

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### creosoteJunior Member

The question: Is there a maximum hull length for a given beam, say 8.5 feet, for powered catamarans? Or is the maximum hull length related to tunnel width and height?

I've seen a few posts that warned about a catamaran or trimaran being "too narrow" and I haven't found trailerable catamarans that were longer than 39 feet. Or...:idea:... it could be that trailerable implies maximum width and length.

So, should I look for ovenable, or microwavable, consumables as presentable on a trailerable, weekendable, floatable, encloseable boat?

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### RonLJunior Member

Looks like I need to get my tape measure rechecked , that is a good looking boat.

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