Offset/Curved Kingpost

Have you seen any design that incorporated an 'offset king post'? This would be a composite structure based on carbon fiber mast layup plans. I'd overbuild it. I understand generally that the downward forces from the mast are enormous.

The goal is to provide slightly more clearance (to the right) in a very tight trimaran cabin.

23 foot trimaran. Coach roof is framed/plywood/epoxy.

 

http://photos.app.goo.gl/TAqtxag79LfRScFw5

 

I think your best bet in the given circumstances (as per your sketch) might be to have a substantial ring frame in lieu of a king post - no worries then about the kingpost getting in the way, however the disadvantage would be that you would have less head room locally in way of the ring frame.
But I am guessing that you won't have full headroom anyway, and would still have to duck / be stooped over when going forward past the mast?

 

Overbuilding is not a good way of designing. It often leads to stress concentrations that will make a structure fail. The offset kingpost can be made to work, together with a ring frame. Depending on the headroom, a ring frame alone could work

 

@gonzo, I'm sorry to say it but none of the four sentences you have written is correct. Not controversial, I only pretend that the OP is not confused with them and makes a bad decision.

 

Gonzo is correct; and both the problem, and the decision to offset the post, is a common one. Try to bond the post to some fore/aft partition as well as transverse framing.

 

@philSweet, sorry to disagree but I think the following:

1. nobody is talking about oversizing anything.
2. oversizing an element cannot produce a concentration of stresses, why?.
3. An offset kingpost does not need a ring frame at all to work, while a ring frame would be desirable..
4. A ring frame can work perfectly without taking into account the headroom at all.

Of course if I am wrong, I will be happy to discuss it but I am not sure that it is interesting for the OP.

That could be a solution without the need for the transverse ring frame. But it is necessary to know the current structure of the ship and the deck, before affirming anything.

 

Here is an example of a bent king post on a Telstar 28 (as you can see no ring frame, no tie-in to bulkhead, and very sexy.)

 

That bent strut does looking rather 'interesting' (but sexy? Ummmm) .
But be aware that the buckling load to cause it to fail will be considerably less than the buckling load to cause failure on a nice straight strut.
Maybe you could consider a goal post type of structure, with straight struts port and starboard supporting a top beam / web frame?