20 botles of beer involved

yesterday my friend argued with me..we were talking about multihulls, I tried to convince him that multihulls can be sailed offshore and he was confidence that multihulls are only for inshore sailing, so we bet, that i will design an offshore multi. I know that it does not have much with our argument, but it is a chalenge for me. The basic keys of the design should be:
1. Fast
2. Ocean going
3. Long term usable (I dont know much about carbon fiber I think it isn't very reliable for long term use).
4. Easy to handle. Like ellens boat, it should be controlable by to or three poeple
5. Money doesn't matter but it should be reliable, so no space technology should be involved.

I am thinking about 60-80 ft tri. Two masts, on the main hull. I am looking for two masted design to awoid huge mainsail and huge jib, with two mast I would have smaller sails and smaller sail area. Other advantege of two mastted design is that the righting arm is smaller, as the rig is lower. And here my vision ends. Any comments? Please help, it is a chalenge for me, I dont know much about ocean sailing, you cant compare baltic or north sea with southern ocean. So any comments should help.

 

Seems like you and your beer have set a tough challenge for yourself....
Yes, offshore multis do exist. Yes, they do work, many quite well.
I'm no expert on offshore multis and so I'll leave the ideas/slamming to others.
On carbon fibre- the material itself is extremely durable and lasts a very long time. It is bloody expensive! The reason so many carbon parts tend to break is because the material is generally used where minimum weight is required and so structures are often underbuilt for what they have to take. On a strength-to-weight basis, well-built CF is roughly four times better than a steel hull. Hence they tend to be built much lighter and so safety margains end up very low. But it's really not worth the expense unless you need that ultra light weight.

 

Here's a link to an off-shore multi designer. Check out his 54 ft tri.
http://www.chriswhitedesigns.com/

He has a good book on the subject.

 

Start here:

http://www.pca-seapeople.org/Magazine/magazine.html

Select Sample articles and then Cooking Fat Circumnavigation

Terho

 

Plenty of them already going round the world! Is that good enough for you? Try different web sites - whr reinvent the wheel

 

I would not say that relativelly small cats are oceangoing boats (even if it is a question of opinion), but trimarans are more seaworthy and you don't need a very big one to have an oceangoing boat. Problem is interior space and price.
They say this one it´s an ocean cruiser and I believe it, but it's a 40ft that has the interior space of a 32ft and costs 500 000euros.

http://www.trimarans.com/pdf_files/dragonfly_1200.pdf

Nice and fast boat, but at that price...

 

For trimarans, take a look at Ian Farrier's designs,
http://www.f-boat.com/