Mast hinge question

[Guest Florin]

It looks like suddenly I have a lot of questions.

Since we decided to go with the hollow spars I recall that some of you guys hinged the mast with the tabernacle method. I kind of like the original method of hinging the mast (like in the plans). Would this work with the hollow mast since there is less area to attach the hinge to the upper mast?

The original method just looks so much simpler to me, and I don't quite care how the tabernacle looks when mast is folded down (no offense to anyone, just personal taste).

Thanks

[Craig]

Florin look at Phil's site for conventional hinges with a hollow mast. He had a solidly engineered design I think.

[Phil Gowans]

Florin,

I think you've hit on the biggest bugaboo of the hollow round mast - the Tabernacle. I've tried a couple of methods and looked at others. None of which seems quite right to me. I don't particular like mine. It is still working, but it is fairly fragile. I've had to put bolts with screw sets into the end grain of the mast. With a little force in the wrong direction it could pop out. The hinge is quite small and the only way my mast stays up is because of the shrouds and stay. If I were to have any give way, the mast would be down in a jiffy.

My original tabernacle was copied from Craigs ideas and he has one that works. Konrad did something different with a tabernacle. I think the type I like the best is one like Scott W. with a support on either side of the mast. This doesn't work too well with a round mast. And don't forget the fact that you have a gaff and hoops to fit in there somewhere when the thing is folded.

[Barry Pyeatt]

The bottom foot of the birdsmouth needs a solid core to eliminate the fragility of the structure when you start drilling holes in it. The plug takes up the compression and allows the birdsmouth to retain its shape and structure. A similar plug should be inserted into the structure when you are fabricating it at the location of the christmas tree at the top. I would make a solid round top section and a center plug that extended down again about a foot to well below the location of all the hardware.

I would also consider placing a plug in the area that the gaff rides on the mast. The plugs won't add much to the overall weight, but they will strengthen and help maintain the structure in those areas getting the stress.

You might also consider wrapping the mast with leather or canvas where the gaff rides against it and either varninsh or oil it so that it takes the wear and rubbing rather than the mast finish and gaff finish. This is a very traditional treatment and it can save a lot of wear and tear.

[Jim Stumpf]

Florin, the Vacationer plans do not allow for the boom to stay in place while the mast is folded down. You need to leave the stump longer and move your hinge up. I know this wasn't part of your question but I had to redo my mast after I found this out to late.

Jim

[Mike Pennington]

Amen, to what Jim said! Raise the base, put the tabernackle below the hinge. Makes a nice package with an A frame on the stern. Helps keep all the stays and lines managable for an easy lift. I believe the Weekender is designed this way. Also you won't regret the head room, that heavy boom is a real Koncker :shock: It will ring your bells!

[Frank Hagan]

The Stevenson's have a free "planlet" for the folding mast tabernacle plans, intended for the Pocket Cruiser, but it might give you an idea regarding Vacationers as well. Its at http://www.stevproj.com/Tabernacle.pdf

I have a page about my solution to the problem of a mast tabernacle for the hollow bird's mouth mast at Frank's Mast Tabernacle. Its pretty simple, but it has worked flawlessly for a couple of years now.

I covered the galvanized metal straps with mahogany strips, and it looks OK too:

[T. Nelson Surbrook]

Frank, do you have a way to lock the mast in the "up" position? If you don't have you considered what would happen if the for-stay failed? BTW I do like the way it looks, very clean.

[Florin {VACATIONER}]

Thanks guys for all the advice, I'll read up on the recomended info and will come up with a plan.

Thanks

[Mike Pennington]

Almost ready to go in the morning, I have been waiting to take this pic of the mast down.

[Frank Hagan]

Frank' date=' do you have a way to lock the mast in the "up" position? If you don't have you considered what would happen if the for-stay failed? BTW I do like the way it looks, very clean.[/quote']

You know, I don't! The forestay is the only thing holding it up. I had planned on a pin that would go from side to side just under the hinge point, but I never put it in. I'll have to think about this now ... :?

[Florin {VACATIONER}]

That looks good Mike,

What are the two boards on the sides of the stub for? Are they just extended versions of the little 8" plates in the plans?

I'm still not sure how I'm going to do it, but I think I'm going to somehow modify the existing hinge (in the plans) to go with the hollow mast. It just may work.

[TexasPhil]

Frank' date=' do you have a way to lock the mast in the "up" position? If you don't have you considered what would happen if the for-stay failed? BTW I do like the way it looks, very clean.[/quote']

You know, I don't! The forestay is the only thing holding it up. I had planned on a pin that would go from side to side just under the hinge point, but I never put it in. I'll have to think about this now ... :?

If the Forestay breaks, I think just about any mast would break under the stress of a full sail (the only reason I can think of the forestay failing) The real force of sailing is transferred to the boat through the says. the mast is just a stiff thing to hold the sail up.

[waynemunro]

hmm.. never shown so dramatically as in recent Americas cup racing...

[Tim Diebert]

I had the distinct displeasure of having my forstay part when in very heavy wind conditions. At that time, my boat had the stock mast tabernacle arrangement as per plans.

I can honestly say that the hinge held the mast from completley collapsing and breaking my neck...though it really tore things up...the whole hinge/tab arrangement was loose and goofy for the balance of the season. But it did hold.

The stay parted because the guy that actually built the boat did not strip off the plastic coating form the wire where he secured the two clamps. He did the rest OK...just forgot the forestay at the head.

My new tabernackle design is much stronger....I figure.

(famous last words)

[Dave R1]

Florin, in case you haven't worked out your mast hinge situation yet, I thought I'd share what I have worked out. Maybe it will help.

I'm using an old hollow wooden mast that my inlaws gave me but I'm using a 4x4 for the stub mast. As it happens, the mast is slightly larger in diameter than the 3-1/2" side of the 4x4 so I planed flats on the mast on all four sides. I cut a plug to fit up into the mast and it runs up a good 15".

I'm using a gate hinge as in the plans on the aft side of the mast. Rather than a hinge on the front I have a couple of 3/16" stainless straps going up the sides sort of like Frank has. At the top of the straps there is a 3" wide band connecting them and forming half a cylinder. This is situated so that when the mast is hinged up, it cannot fall forward. I expect that is a belt and suspenders sort of thing but I doubt it will fail. It might be able to support the mast and sail if the forestay parts since there will also be two pins through the mast.

My plan for pinning the mast in the upright position is a little slower than the one in the plans. It calls for a four button-head machine screws threaded into couplers epoxied into the mast--two on each side. I might find this overkill and switch to just one bolt on each side but we'll see.

I'll try to get some pictures this evening and get them posted.