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  #11  
Old 09-28-2011
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Used to be done by Thames sailing barges to get under the fixed bridges on the Thames.

See Comedians sail under London's bridges [6 October 2003]

These 80 footers were sailed by a man, a boy and a dog. Dog was a burglar alarm when they were either alongside or dried out.
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  #12  
Old 09-29-2011
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Most of what I have seen called a tabernacle are, according to what I grew up knowing, a mast hinge, not a tabernacle. The earlier pic posted by Ulladh is closer to a real tabernacle, with the pivot point located away from the mast end.

The majority of tabernacles I have seen on US built/owned boats have been home built affairs, most functional, but appearance/quality vary a great deal.

One I liked the arrangement of, built of heavy aluminum channel, the owner had clamp on weights for the bottom of the mast that improved balance so well you could almost 'throw' the mast into place.

I'm in the process of downsizing, and a true tabernacle is on the equipment list for the next boat.
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  #13  
Old 08-03-2012
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Re: Folding Masts

I have a 30 ft Seafarer I just purchased and yes I will be trailer-ing it on a custom 4 axle trailer with a 1 ton tow rig and wide load permit. Its combined gross will be right at the design limit of the 1 ton's 21000 lbs. So no comments on it can't be trailer-ed. I drove semi for three years... if its under 13'6 high and only 10 ft wide it only needs a wide load permit, daytime running (ok with me) but does not need escorts. So I am doing it as all my toys have to live at home when we can't afford to feed them. It cost nothing but a little tease and aggravation sitting in a shed over winter or when it has to. I also can haul it to any water I please. That being said. I need to do something about its mast. It also will be my work location housing when working away and near water (as compared to an RV that most do).

On my 27ft sailboat that is currently on the trailer (and coming off and hopefully sell to make way for the 30), I designed a raising and lowering system off the trailer winch but then I need to unpin the base and carry the mast to cradles forward and aft for towing. Id like to not have to do this. The 30's mast is much more robust and heavier. And I'd like to be able to clear bridges under way. I looked at the weight balls above and it works for some bridges... but I want it down to three times it's thickness on the cabin.

I have an idea, and I'm looking for previous examples... I want to have the upper two third or so tilt aft, and the bottom third or so tilt forward and dual/triple pivot down without un-staying (if the mathematics work on pivot positions). I intend to change out the base with a cam system that raises the mast a few inches to tension the stays for rigged mode, and lowers the mast for releasing the stays to allow for initial pivot at the hinge points. The cam would be in full compression mode when in rigged mode and transfer the forces into the base and hull as designed.

I want to it to operate on light long hydraulic rams (custom built by me, I have a reasonable shop with machine tools) and set up to raise and lower on hydraulics by operating a couple valves operating the pivot rams and the cam. The top section ram will actually always be in tension mode so light and skinny operating a cable in tension works just fine. The lower will have a little compression forces to initiate pivot, but after that is tension. Lateral stability on the way down needs to be worked out yet, but I have an entire SS stay set from a 27 ft I can modify and figure out crossing brace lines off the pivot hardware I think.

Just thought of another cable only system to operate the pivots... no hydraulics... same pivot system and base... but simplified. Hmmmm, I like this.

Anyone seen anything like this?

Dave

Last edited by dem45133; 08-03-2012 at 05:34 PM.
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  #14  
Old 08-05-2012
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Re: Folding Masts

No comments? Somewhat surprised. I can't be the only one with a larger than typical trailer sailor with this question.

(Really I did this post to move it back up in the listing and be more visible.)

Dave
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  #15  
Old 08-05-2012
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Re: Folding Masts

I'm having a hard time picturing what you are proposing to do with the hydraulic system. Is it fixed to the boat, or the trailer?
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  #16  
Old 08-05-2012
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Re: Folding Masts

I've never seen anything like that. I hope you take good pictures and post a video of the completed rig, and let us know how it handles heavy(ish) weather. I like the idea of cables-only better than hydraulics, especially if you're on saltwater -- unless I am picturing your plan differently than you are. Sketch this up and post it!

(paul, the hydraulics would be fixed to the boat, as I am picturing it: one for each of the two joints in the mast.)
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  #17  
Old 08-05-2012
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Re: Folding Masts

Quote:
Originally Posted by rodbeuk View Post
I used to own some trailer sailboats, but now have a 1988 Hunter 33.5, but with the fractional rig it's too tall to get under the KY Lake bridges. I am searching for a way to make my mast folding rather than unstepping it.
Hello Rodbeuk

Yes, I have similar questions and have been thinking on it. Apparent, folding mast setups on larger, long, and heavy masts like yours and mine present some interesting issues to solve.

On my 27 Buccaneer I lower the mast via the trailer's high mounted winch lowering to the aft and onto a temp cradle at the stern. It works just fine but then I have to un-pin the base and carry the mast forward for stowing.

I now have a 30 ft Seafarer I will be trailering (yea I can) but it's mast is much longer and heavier than my 27's. I'd like to investigate folding options where it folds down with the base 1/3 (or so) going forward and the upper 2/3 (or so) pivoting aft... and stay fully stayed.

I'm getting old enough that a "push button mast raising and lowing system" is starting to look pretty attractive. It must to others too, but as someone else put it there's not all that much yankee ingenuity happening anymore.

Has anyone ever seen such a system? Cables?, hydraulics?, compressed air? What are those million dollar toys doing? They are push button everything aren't they? If some factory can design and build something I can too.

I have a simple lateral force "in motion" stability system worked out mentally for the whole traverse from full up to full down... even in a worse case cross wind.

I have the initial pivot movement mast elongation problem worked out conceptually anyway (for my the Seafaer's mast setup) so as to not un-stay. I may be able to design a pivot lock release catch system up through the center and be operated from inside the cabin below the mast...humm have to think on that more. Just came into my head as I was typing.

These are all old very simple systems I'm thinking in. Nothing all the magical about them.

Leaning toward weather protected simple 12vt gear reduced motors, cable drums, and cabling/pulley systems... with manual hand crank backups. Conforms to the KISS rule. But hydraulics are not out of the question either yet, but you know that just when I need it bad in a river current and a low bridge coming up, that's exactly when the motor or engine driving the hydraulic pump will fail. 12 vt Electric and cabling is readily available on-board and can be manually backed up more easily.

Getting closer on concepts... time to get the old drafting table uncovered and start drawing it out and work up the math. I prefer it over my CAD Program actually.

PS, Are you all telling me (through the lack of words) that no-one, or no company has done such a thing for the push button only million-aire owners? I actually find that hard to believe where money was no object. Oh... never mind, they just pay the marina. I forgot they pay others to do things for them (dummy me!). I would rather not have that cost... and I'd really want it available under way... for multiple reasons.


Thanks for your thoughts...
Dave

Last edited by dem45133; 08-05-2012 at 02:05 PM.
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  #18  
Old 08-06-2012
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Re: Folding Masts

Tabernacle installed on Kirie-Elite 37. will allow the mast to be lowered to 45 degrees aft. Can easily be performed by two people.
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  #19  
Old 08-06-2012
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Re: Folding Masts

Thanks... I'll take a look. But in all honesty... I have 1 person... i.e. me. While my wife will likely be with me... her back can not do any work of any kind anymore. I'll will be building a lift so she can get from the cockpit to the cabin floor. She won't be on deck. She can run the helm...but everything else I have to do. So the mast system needs to be pretty much a setup the systems and push a button. Besides I'm not 25 anymore either.
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  #20  
Old 08-06-2012
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Re: Folding Masts

Quote:
Originally Posted by PaulinVictoria View Post
I'm having a hard time picturing what you are proposing to do with the hydraulic system. Is it fixed to the boat, or the trailer?
My initial thought was that a separate valve controlled hyd cylinder operating each pivot independently and mounted on the mast sections. While this is easily doable... (Check out the geometry of a track hoe sometime) its not easily backed up by an alternate manual only mode. Thinking guided cables and 12vt motorized drum winches now. Its a bit old fashioned... but conforms to KISS and if the motors are double ended...there is a place to attach a hand crank in an emergency and operate the winch manually. Someone likely already builds these for some kind of marine app. There's always the bumper winches for the four wheelers too. They are plenty large enough for the forces. I still need to calculate forces for sizing the components.

When up.. I want it ready to sail.. all stays tensioned. When down, laying in cradles just above the cabin trailering and low low bridges, really bad seas, or whatever.

Last edited by dem45133; 08-06-2012 at 10:25 AM.
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