Tabernacle design challenge

[troy2000]

I'm throwing this out off the top of my head. To use an old Madison Ave cliche, let's run it up the flagpole and see if anyone salutes....

I understand the principle of a tabernacle. But as a general rule, any mast that's stepped in a tabernacle is stayed .

I'm working on a sharpie design, and will probably put a traditional cat ketch rig on it. It's going to be trailered. Like the originals, I'd like to have unstayed masts. I'd also like them to be revolving masts, to take the pressure off the sprits so I can let the sails run free if I get overpowered suddenly, or if I simply want to slowly drift downwind without dropping sail.

In the old New Haven sharpies, they simply muscled the masts into place, and pulled them the same way. I could do that right now, but I'm 60 years old. Realistically, I'll probably not want to be muscling masts around in another fifteen or twenty years. I'm quite familiar with gin poles, and I realize I can use a sprit as one. But there's gotta be a better way.

So here's the challenge. I need some sort of a portable or permanent tabernacle setup: one where I can feed the foot of the mast into the tabernacle, raise the mast up (much easier to do with the foot under control), then drop it through the fore deck/bridge deck into the mast step. At which time the tabernacle setup either gets stowed or ignored, since the mast is now securely in place.

That part isn't really much of a challenge. It can't be that hard to come up with a setup where you stuff the foot of the mast into a tabernacle, clamp it into place, raise the mast, then loosen the clamping mechanism to drop the foot of it through the foredeck or the bridge deck and into the mast step.

The fun part is engineering a way to easily pull the mast back up, out of the step and the deck, and clamp it back into the hinged tabernacle--so you can lay it back down and trailer on home.

Anyone have any ideas, or am I on my own here?

[gonzo]

You could have a slot on the deck with a closing panel. Set a pivot on the deck and when the mast is down, close the slot.

[Eric Sponberg]

Originally Posted by troy2000

So here's the challenge. I need some sort of a portable or permanent tabernacle setup: one where I can feed the foot of the mast into the tabernacle, raise the mast up (much easier to do with the foot under control), then drop it through the fore deck/bridge deck into the mast step. At which time the tabernacle setup either gets stowed or ignored, since the mast is now securely in place.

That part isn't really much of a challenge. It can't be that hard to come up with a setup where you stuff the foot of the mast into a tabernacle, clamp it into place, raise the mast, then loosen the clamping mechanism to drop the foot of it through the foredeck or the bridge deck and into the mast step.

The fun part is engineering a way to easily pull the mast back up, out of the step and the deck, and clamp it back into the hinged tabernacle--so you can lay it back down and trailer on home.

Anyone have any ideas, or am I on my own here?

Troy, look at the Seapearl 28 which has a cat ketch rig (I designed the masts, although not the tabernacles).

http://www.sailboatdata.com/viewreco...?class_ID=4340

The Seapearl 28 boats had aluminum half-pipes for holding the free-standing masts. Look at the sailplan in the link above to get a better idea. The forward mast tilted aft, and the after mast tilted forward. To raise, pull the masts up with a halyard--they were held at the top of the half-pipe by a hinged clamp ring also fashioned from the pipe. As the mast arrived at the full-up position, it slipped down a few inches into the step. Reverse the procedure to lower--lift the mast up out of the step a few inches and tilt it down. The masts were light enough for one person to handle, this on a 28' trailerable boat.

Google Seapearl to find other links and history of these boats.

Eric

[troy2000]

Originally Posted by Eric Sponberg

Troy, look at the Seapearl 28 which has a cat ketch rig (I designed the masts, although not the tabernacles).

http://www.sailboatdata.com/viewreco...?class_ID=4340

The Seapearl 28 boats had aluminum half-pipes for holding the free-standing masts. Look at the sailplan in the link above to get a better idea. The forward mast tilted aft, and the after mast tilted forward. To raise, pull the masts up with a halyard--they were held at the top of the half-pipe by a hinged clamp ring also fashioned from the pipe. As the mast arrived at the full-up position, it slipped down a few inches into the step. Reverse the procedure to lower--lift the mast up out of the step a few inches and tilt it down. The masts were light enough for one person to handle, this on a 28' trailerable boat.

Google Seapearl to find other links and history of these boats.

Eric

Thanks for the suggestion and the link, Eric. Am I right in thinking these masts are basically surface-mounted, with the tabernacle acting in place of a mast partner? I haven't found any pictures yet that focus on the tabernacle and base of the mast.

What I want to do is pretty much what you described--except that instead of dropping a mast a few inches into a step, I'd like to drop it through the deck to a mast step on the keelson. Like I said, that's the easy part; the interesting part is to pull it back up and out of the deck so I can lay it down.

[troy2000]

Originally Posted by gonzo

You could have a slot on the deck with a closing panel. Set a pivot on the deck and when the mast is down, close the slot.

Gonzo, that was my first thought; maybe even doing it Dutch-style with a counterweighted mast. But I don't think there's going to be room.

[Zed]

Fwiw.

[Eric Sponberg]

Originally Posted by troy2000

Thanks for the suggestion and the link, Eric. Am I right in thinking these masts are basically surface-mounted, with the tabernacle acting in place of a mast partner? I haven't found any pictures yet that focus on the tabernacle and base of the mast.

What I want to do is pretty much what you described--except that instead of dropping a mast a few inches into a step, I'd like to drop it through the deck to a mast step on the keelson. Like I said, that's the easy part; the interesting part is to pull it back up and out of the deck so I can lay it down.

The aluminum pipes themselves extended whole down to the keel, and were split only above deck. So yes, essentially the composite mast had a support at or just below deck level, as I recall. If you want more detail, you can contact Marine Concepts in Tarpon Springs, FL:

http://www.marine-concepts.com/

The Seapearl 28 is no longer built, but they might know more about the masts were tabernacled.

Eric

[troy2000]

Originally Posted by Zed

Fwiw.

That one kind of flabbergasts me. Was it Phil Bolger who decided to eliminate the stem to make room to swing the mast, or are there more like him in the world? Blows hell out of my "there isn't room to pivot them through the deck" argument....

I admired Bolger tremendously, and I bought several of his books over the years. But I wouldn't be caught dead in a lot of stuff he designed, no matter how well it works.

[Zed]

No idea... that was snapped in the middle of dope smoking hippy country. It's 'alternate' and that is about all I know about it.