Wednesday, December 30, 2015

Tilting Masts

At some point in time in the hopefully not too distant future, I will hire a crane and flip the boat over to begin building the decks and superstructure.  At that point I'm hoping to have an idea of where and how my mast - or masts - will be built and installed.

I don't yet.

The greatest complication in the whole thing is that they must be lowered easily.  There are three local bridges of concern with which I'm attempting to avoid concern.  Two of them are railway bridges that presently are easy to have swung with a day's notice, but the third is a highway bridge that can take weeks to arrange its opening.  And the last time they did it got stuck there and really pissed off the unwashed masses.
The railway is also suggesting that a full time operator is overkill and only required during freshette since that is the only time of year the gravel barges need an opening.  Otherwise an appointment arranged at their convenience will do just fine thank-you. The barges can get under when the Fraser is low, though they often scrape off the top of the load on the bridge structure.  Having the paint scuffed on a 100 year old bridge does not seem to be of concern to them whereas a reasonable salary to a single rail worker is.  Being a large, quite pushy corporation that usually gets its way (a coal train now can legally be over 2 miles long, and don't get me talking about oil transport) - the railway will likely be satisfied.  So I must be able to scoot under.


Railway Bridge at Mission

What I have decided so far (or am close to deciding) is that my mast or masts will be hybrids, as outlined and discussed by members of the Junk Rig Association and in the book 'Practical Junk Rig'.  That is: a lower section of extruded aluminum and an upper section of wood - either solid or hollow.  Since weight is a concern I'll probably go hollow.

The hinge mechanism has my thinker working a bit harder though.  A conventional tabernacle has space requirements that may be hard to incorporate in my boat.  I do like the idea of an actual hinge right in the mast.  It has been done before, and a similar arrangement is being considered by Dmitry Orlov for Quidnon.
And living where I live I have access to fabrication and machining facilities where such contrivances can be made up.

All food for thought...that must be eaten and digested soon.


10 comments:

  1. Have a look at Pete Hills Oryx. JRA news letters.

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  2. Just riffin here and probably out in left field but Bolger had totally counterweighted masts that could be swung up and down with mere hand pressure. His were lower but the hull was also rounder with less initial stability overall. Based on the stability of a trilo and your 10 beam and not meant to heel all that much anyway maybe just extend the tabernacles upwards to where you were considering breaking the mast? From the pivot down now, with this extra area, counterweight the upper part. Perhaps too much weight up too high but probably not much more than the weight of the reinforcing required to bolster said broken mast joint. No hard and fast rule about not adding shrouds either. Colvin left his a bit loose and it was meant to stop excessive whipping up top. I added two shrouds per side on our junk rig we built onto a Pearson 32. By the way: Colvins (chinese lugsail) sailmaking book has a lot of rigging details too plus some tips on how to sail the junk rig. Loose leaf bound but well worth the bucks. His description of how to arrange the sailcloth so it feeds smoothly through the machine is priceless and really helped me when I sewed up ours. Cheers and happy new year here on Dec 31st at 5 pm CST.

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    1. "By the way: Colvins (chinese lugsail) sailmaking book has a lot of rigging details too plus some tips on how to sail the junk rig. Loose leaf bound but well worth the bucks."

      Sounded good, until I saw that Amazon lists it in a mysterious way and for $195! Tell me there's a better option please.

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  3. Thanks Robert. I've been kicking around a tabernacle with the base of the mast going down into a well. I could easily make the bottom of the well above the waterline to drain and still get a lot of bury from there up to the top of the tabernacle a few feet higher than the cabin top. The well could also serve as a rope locker and anchor storage though I'd have to unstow it to drop the mast -no big deal. Counter weighting makes a lot of sense since I could get a lot of leverage for the weight. Aluminum flag pole with tire weights set in epoxy in the bottom few feet?

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    1. And Happy New Year to you too! I apologize for my temporary lack of manners due to the wine I'm drinking right now :-)

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    2. Intriguing mast set-up. The well doing double duty makes a lot of sense if it is set up to drain quickly if a rogue wave or whatnot. Hard to say how likely a quick dropping would be if a ton of stuff in the well. Tough to say if that will be enough weight to counter the top portion. Intuitively I'd say not enough but who knows? Really nice to be able to drop masts so quickly.... kinda in the same vein as dropping sail so quickly with the lug rig. Bolger commented that if his boat was squirrelling around in a wind while tied to the dock that by merely dropping those masts the boat tamed right down. Yet another bennie of easy to drop masts. No poor manners detection on my part at all! Cheers.

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  4. Thanks for the comment Robert. It came in as a duplicate post so I deleted one for the sake of tidiness. If I go with a well, it will hatched over with a watertight hatch and also will seal around the mast somehow. With a good size drain to boot I should be ok. As for counterweighting the mast I guess a lot of it depends on the size of the mast. A single mast arrangement for this size of boat (say 10,000 lb, displacement most of the time) I probably need around 600 s.f of sail but I don't really know for sure. Then, will it be high aspect ratio or low for shorter but maybe stouter mast? Again, I don't really know. I'm presently trying to absorb as much as I can from "Practical Junk Rig". A super book but not an easy read - for me anyway.

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