Rob,

    I have a 34 foot trimaran (an Andrew Simpson Shifter MK2) that was built here in Texas.  I bought it as a fixer upper about 10 years ago.  We sailed it around for 6 years or so, and decided it was too small.  About that time the boat looked as if it would sink at the dock, so I brought it home to my farm to fix up to sell.  Then an identical unfinished center hull was being sold for a great price so I bought that.  The intention now is to join the two center hulls together to make a 34 foot biplane cat.  It won’t be fast (the L/B ratio of the hulls is 7 to 1) but I’m not sure I really care.  We sail every year in the Caribbean for 3 weeks and from that experience I think I really just want something that’s stable and will sail downwind or on a reach OK.  If I have to go upwind I’d rather just start the diesel or go to another island that’s downwind or a reach.  I like the biplane because I figure it’ll make the hull beams less complicated (they have to demount to get it to the coast), and I’d like to split the rig to make it easier to handle.  I also really don’t like getting out of the cockpit when it’s rough so I’d like to simplify things so I can handle it from the cockpit.  Just rough figuring puts the boat at a max displacement of 8-10K pounds, a beam of around 20 feet, masts about 40 feet long (max length of my shop), sail area around 6-700 square feet.  I’m leaning toward a tube mast rather than a wing mast.  I’m looking for easy to build and bulletproof, I’m not so concerned about the weight.  Still a couple of years away from starting, I’ve been adding on to my house last 3 years, got done with that, and now the wife just ordered another master bathroom.

Thanks,

Jerry Barth

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From: harryproa@yahoogroups.com.au [mailto:harryproa@yahoogroups.com.au] On Behalf Of Rob Denney
Sent: Tuesday, December 29, 2009 5:34 PM
To: harryproa@yahoogroups.com.au
Subject: Re: [harryproa] Masts

 

 

G'day,
There are a number of ways to build masts, depending on size and builders set up.  My wing mast will be from flat panels, tube masts can be from either flat panels or in a one piece pressure mould.  Tow makes sense for both as it is cheap and has no wastage.  Uni could be used if it was a non tapered section.

What size of boat have you got, and are you looking for a light as possible mast, or an easily built one?

First step is to get the engineering done.  This costs about $Aus1,000, depending on what you require. Once the engineering is done, you will have enough information to cost the materials and decide if the weight savings justify the cost.  Plans cost another $1,000.

There are a couple of pro builders capable of building them as well, if you don't want to do it yourself.

The strip masts are still standing, so the method worked, but it is more work than it needs to be, and the laminate schedule is not ideal.

rob

On Wed, Dec 30, 2009 at 12:38 AM, Jerry Barth <shredderf16@sbcglobal.net> wrote:

 

Hi,

     I’ve been lurking a couple of years.  What’s the latest method of building the carbon fiber masts?  Are you guys still making strips out of tow or is there an easier way now?

Thanks,

Jerry Barth