Tuesday, May 17, 2016

Rig Options with Stayed Masts

Since I have decided finally to go with stayed masts and can design the masts and rigging with far more confidence than an un-stayed setup, the doors open to more options for a rig.

I have not thought about a bowsprit before - mainly because it greatly increases my overall length - something to avoid if one moors in a marina.  I'm not sure if we will or not, but a bowsprit allows us to carry a jib, and if we did, why not make the mainsail larger than the foresail and call her a schooner?


If I use Dennis's idea of using the lazy jacks as temporary pivot aligned side stays to raise and lower the masts, then I can get away with five stays for the whole rig - two aft side stays per mast, a running fore stay, and then a running triatic between the masts.  I could lower the aft main mast by simply easing the running triatic - no gin pole required - then lower the foremast by easing the fore stay.  We'd need a gin pole for this one.  Both masts would have to be on the centerline to use a triatic, and the foremast would lay over top the aft one when down - a bit cumbersome but only endured long enough to get under the bridge.

RLW in an email, put me onto using Amsteel rope for the stays instead of galvanized or stainless wire rope.  I never knew about this stuff before and it would certainly work well.  I can't believe how strong it is and it even comes in colours!

See the specs here:

Food for thought while I get organized to continue building.

22 comments:

  1. my two bits: as a trucker I purely hated wire rope.

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  2. I have a really STUPID idea that I came up with while writing my book in a somewhat analogous situation to your boat. YOu have a well for the engine. Have similar wells for the masts. NOT a tabernackle. Going under a bridge you will be in deep water. Just lower the mast straight down into the water under the boat until it's low enough to clear the bridge. Might not even have to lower the sails..

    yeah stupid. but I can't get it out of my head.

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    1. It tends to be quite shallow under most of the bridges I would want to go under. I appreciate the 'lateral thinking' though Everitt. I read somewhere about a guy who made legs that operated from the four corners of his barge houseboat that allowed him to sit stationary over an uneven bottom while the tide went out from under him.

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    2. Oddly enough that's what prompted my thinking. I've been reading about 'spar bouy' designs lately (sea stead). Earlier you mentioned a cement/concrete ballast. Attach it to the four legs, etc, etc, etc.

      Lateral thinking is what I do. I'm a writer.

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    3. I thought about the water depth as well. Using the Intracoastal Waterway (ICW) as an example, average depths along Florida are only 10 to 12 feet. However, lowest bridge clearance is 50+ feet. Everitt's inspiration and then those facts got me thinking about telescoping mast possibilities.

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      So..for the cost of a cup of coffee (or two) you can (hopefully) have a few hours of escapist entertainment.

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  3. Have you thought of a shipable/removable bowsprit? I have seen some very salty classic craft that have bowsprit that retract when at the dock. If I recall correctly there was a forestry to the bow and the jib was set flying, but I'm sure there are a multitude of ways to do it.

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    1. Thanks Robert. I would have the bowsprit removable or hinged for sure.

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  4. Bowsprit: What about one on a hinge, that can fold back?

    Everitt: Not such a stupid idea. Unconventional thinking is the only thing that ever leads to innovation.

    Telescoping mast? I just started thinking about this possibility. Couple interesting links:

    http://4.bp.blogspot.com/_Biv6Jp342HE/TJJ4F89smRI/AAAAAAAAG3Y/Ea3zjm5swVo/s1600/Pulley+and+Cable+Detail.png

    http://www.willburt.com/products/telescopic-masts/

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    1. Thanks Yoda, I kicked around telescoping masts quite some time ago. I'm still stuck on stayed masts from aluminum pipe - lightweight and easy to tilt back.

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    2. OK on stayed masts. I'm still pondering.

      Here's an oddball question: Assume I have two 20' pieces of aluminum tube. One slightly narrower to fit inside the other. If the goal was maximum telescoping extension, how much smaller pipe, would you estimate, needs to be left inside of the bigger pipe, to maintain full flexural strength?

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    3. It depends somewhat on the fit. If it was really tight - what we call an interference fit where the only way to get them together is to shrink one with liquid nitrogen and expand the other with heat then I imagine 6 or 8 inches would do the trick. However that blows any hope of telescoping. Loose enough to telescope then the bearing points will be at the top of the larger tube, and at the bottom of the inner tube. In that case I would say 10 to 15 percent of the length.

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    4. Nice analysis and explanation. Similar to what I was thinking, though without the aluminum experience that you have, so thanks.

      Even with 20 percent left overlapped while extended, that would still enable a maximum 36-foot mast. Less if also in a tabernacle or buried below decks. Still, it seems like plenty for likely triloboat use.

      Next steps:

      1. Would a reduced, de-telescoped, 21-foot mast clear most bridges? If not, the whole idea is kind of silly.

      2. How to raise and lower (telescope) such a beast? Hmmm ...

      I realize this is a bit off-topic as you're now going "stayed", so just ignore if you like.

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  5. The next logical step is to have the bowsprit double as the gin pole, with the base at the base of the fore mast. Put an inexpensive ATV winch with a block at the bow and a remote control in the cockpit. drop the sails, move the lazy jacks to the pivot points, then extend the winch cable, the bowsprit comes up and over, which automatically allows both masts to rotate aft and down. It probably would make more sense to lower the masts independently via the triatic first, but in a emergency both could be lowered simultaneously. I would like some independent way to secure the mast so a broken piece of rigging does not bring everything down, but most stayed rigs suffer from this to some degree, the other alternative is the same as above, but put the masts in tabernacles so they can be independently secured. Risk/cost ratio worth it?

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    1. Thanks Dennis. I'm working out the geometry of such a setup minus the ATV winch... I'd prefer to use a manual one. I think that once everything is up that quad stays on each mast would give some safety and redundancy.

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  6. On the topic of your stayed masts ...

    Amsteel rope: Never heard of it before, so I checked it out online a bit. Sounds pretty good.

    * The strength info I found for Amsteel rope and stainless steel cable allowed an interesting comparison. Unless I'm misreading columns and comparing apples to oranges, it seems that the Amsteel is a bit stronger (1/4" diameter example).

    Amsteel: http://www.samsonrope.com/Pages/Product.aspx?ProductID=872

    Cable: http://www.steelwirerope.com/WireRopes/Constructions/MarineGrade/1x19-stainless-steel-wire-rope.html#.VzyRCPl97b0

    * Not sure what dimensions you have in mind, but the 1/4" diameter is about $1 USD per foot and the 1/2" is $4 per foot. That is, unless you go with West Markup ... oh sorry ... I mean West Marine. ;-) In this case, they are 25-70% higher than other vendors I found.

    So, for stays, what diameter do you think you'd need?

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    1. RLW told me that he uses 7mm sized Dynex - similar to Amsteel. Both are UV protected synthetics.

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    2. "Both are UV protected synthetics."

      UHMWPE if I'm not mistaken. Makes me wonder about their UV protection claims, as HDPE, etc. don't have any. For a use involving continual exposure to the sun, it might be worth digging into a bit.

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    3. When I get 'close to the wire' I will dig deeper for sure. Sure don't want the rig toppling. I'm going to have some redundancy though, so if any one stay fails nothing topples...

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  7. Some pix online of the traditional working scow (40' or so) built in Crystal River, Florida a few years ago and it's bowsprit treatment. As I recall merely some doubled 2X10s and hinged to come up and back. Simplistic but effective. Their rig was a deck sweeping, murderous boom on a gaffed sloop rig. I used simple galvanized wire on my chinese lug rig and it worked well and echoed by St. Colvin in his chinese rig book. Glad to see you are going low aspect and spread out. Add a boomkin and REALLY stretch it out for 1001 sail combos to play with ;) Looking good.......

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    1. Thanks Robert. I'm thinking on the same lines now for the bowsprit hinging up and made of lumber. I've kicked around a lumber/plywood box structure.

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