Monday, January 18, 2016

Getting Shippy

The tall masted high aspect ratio rig in the previous post probably would have the best sailing characteristics of all I have drawn so far...and I only base that on empirical evidence gleaned from research and from comments and advice from those who are helping me.  The more that I think about the downsides though, the more it bothers me.

I do want to get under the bridges.  And I don't want to spend about $6000 for a pair of aluminum flagpoles.

So I've been back to the drawing board and have come up with a a 3 masted rig as suggested by Robert.  The fore and aft rigs are sprit sails of just under 100 s.f. each and the masts and spars can be made up with common lumber.  The masts themselves are low enough to get under the bridges without lowering them.

The main is a junk sail around 300 s.f. and is low aspect ratio.  The mast would only need to extend slightly more than 22 feet above the cabin roof.  If I made it with an aluminum extrusion (straight tubing)  I may be able to hinge it and sleeve it to lock - as described in some JRA posts and the Tammy Norie blog.

I'm still in the thought process with the whole thing but I'm hoping I'm on the right track for the boat I really want.  Giving up the bridge capability would be a big compromise.


8 comments:

  1. you haven't reconsider the CrabClaw?
    To quote Dave Ziegler
    " Handling our Crab Claw Rig took some getting use to, but is very simple. Hauling the tack
    downhaul raises the sail to more vertical attitudes, slacking allows it to recline. The leeward
    sheet is the ‘active’ one, hauling its limb down and in. Then the windward sheet is hardened as
    a stay on the upper limb. There’s no reefing, per se... just roll the sail toward horizontal,
    directing force upward and converting heeling moment to vertical lift. The limbs spring inwards
    to absorb the shock of gusts.
    To center the sail, pull the upper limb down until the sail is level. The sail is usually pointing off
    one way or the other, so one yard end will be ahead of the other. Pull the lead sheet against
    tension on the other to square the yard (and sail). Make fast and, if stowing, shockcord the sail at
    mid-head to create the ‘delta wing’ shape. This acts as a riding sail, bimini and rain catcher. It
    can be left standing to about 20 to 25 knots before it becomes too obnoxious."

    If I recall correctely he said (somewhere) that the problem they had with that boat was 'skiddin' sideways...it didn't have enough keel. That was fixed with leeboards

    I thought he indicated that the CrabClaw worked well.

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    1. I still like the junk. Easier to stow than the crab claw for sure. It does have its merits and I did a lot of looking at it since you first suggested I check it out.

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  2. You are blessed to have some really talented and experienced sailors weighing in on your design process and I am not referring to me (although I do have some good things to say, at least in my jaded eyes anyway). I refer (so far) to Dave Z. and RLW: both vastly experienced and with open minds design wise.

    In the end it isn't rocket science and that is part of the charm actually. If you're led to feeling the bridge issue is paramount then so be it. Gotta say the three master is charming but would work better on a longer waterline. In the end you can't have it all but fun to get there.

    If exploring the crab claw Hans Klaar used it very successfully on his 70' polynesian style catamaran (deck space similar to yours) with lots of pix and write-ups here and there on the web. Daves write-up regarding his experiences with the little 16 trilo is good as well. Way enjoyable to watch this come down. Much like when Dmitry Orlov was open source designing his Quidnon design.

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    Replies
    1. Your're up there with the rest of them :-)

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  3. Regarding Masts, I do know that MingMing II used an aluminium lamp post for about £700 if I recall?

    https://www.youtube.com/watch?v=E-IbUt-CTRQ

    I don't know if that's worth investigating or even if they're tall enough for your rig. As MingMing II is quite a bit shorter than yours.

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  4. My best bet around here is to use schedule 40 six inch pipe. It is over 6.5"o.d with a .280 wall thickness and is 6000 series alloy. I can get a 20 foot length for under $500 CDN. I can then build up a wooden upper section from structural Douglas Fir which I have quite a bit of. I called a local company that makes the light poles - their prices are crazy high.

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    Replies
    1. Alan,

      Technically, what is the difference between that Sch 40 pipe and the flagpoles mentioned in the post costing $6,000? Also, does the pipe you selected have any specific terminology to identify it when sourcing, or only as you have described it here in comments?

      Yoda

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    2. The flagpoles are tapered. The pipe is straight. Shedule 40 Aluminum pipe is sold in various sizes. 6 inch pipe will have an internal dimension of 6 inches. The difference between pipe and tube is that 6 inch tube will have ann external dimension of 6 inches. The pipe is 6000 series aluminum, where tubing can come in various alloys.

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