Subject: [harryproa] Re: Mast raising
From: Mike Crawford
Date: 7/2/2006, 8:03 PM

  If you can keep that leeward hull in place as it rotates from horizontal to vertical, then there shouldn't be any problem with the size of the mast.  Given the length of the beams, a #14 winch at 16:1 should be enough to bring the leeward hull into place with a 22m wing mast.  Though I'm not familiar with the size of winches used on the Harry's, my guess is that you'll have at least a #14, which is the smallest self-tailing size offered by some vendors. 

  If this is not enough, it would be simple to double the purchase with a block.  If you want even more than 32:1, then you could have a single line going from the trailer to the first beam, back to the trailer, up to the second beam, back to the trailer again, and then up to the winch.  That might be even be enough to lift your tow vehicle if you put some muscle into it..


  For me the question then becomes how much help you're willing to require.  If you can get a few people to lend a hand, then the Harrigami setup described in the article should be fine.  It's certainly the simplest and cheapest way to go, and there's a lot to be said for both.

  I'd probably choose to spend more on a trailer to help ease the process, though.  This would be partially to save on boatyard costs, and partially to allow two people to launch in areas that don't necessarily have paid help. 

  I think even a Visionarry could be kept to an 11' / 3.3m trailering width if the leeward hull could be stored on its side on the trailer beneath the cockpit.  My first thoughts on this would be to:

    - Create a bunk that could hold the ww hull upright on its own,

    - Create a detachable moving bunk for the lw hull with its own wheels that could be lowered and used to move the hull out away from the trailer,

    - Add two long horizontal arms that could be used to hold the lw hull in place the proper distance away from the ww hull, as well as keep the trailer assembly together when launching and retrieving the proa,

    - Give the lw hull bunk assembly the ability to pivot to vertical without sliding towards the ww hull and trailer,

    - Add some sheet blocks to the trailer and akas through which the winch line can be run,

    - Add two short vertical arms with soft rollers that could be inserted into the main trailer and used to catch the beams as they rotate down to horizontal,

    - Add some block attachment points to the lw hull so that it can be winched tightly towards the ww hull once the beams are in place.

  I'm not exactly sure how this would be done in a real world situation, though.

  The bunk keeping the ww hull vertical would need to be pretty strong, especially if it's going to hold everything in place while on the road.  Perhaps it could be supported while by the lw hull bunk once it is in place under the ww hull, and by a temporary support arm under the cockpit when the lw hull bunk is away from the main trailer.

  The lw bunk might need a roller bearing and expansion arm/track to support it until it is moved far enough from center to get the inboard wheels down (assuming the outboard wheels can be dropped while the trailer is still whole).  The wheels would also need to pivot 90 degrees to make the transition from assembly to launch.  Alternately, there could be two sets of wheels, but that seems a bit excessive.

  Ideas on how to improve this setup, especially on how to make that lw hull bunk work, are welcome.  I don't mind seeing my ideas trashed as long as something better results.  Rob could probably solve this in a weekend if I were actually building a boat, but I've got five years left of lurking in this group before I get to that stage.

       - Mike

oceanplodder2003 wrote:
Saw that, my concern was at what mast length would it become an issue,
considering that if I go for Rob's una rig I'm assuming the mast must
be taller, and I think Harry's is longer than Harrigami to begin with.


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