Gin Pole (Mast raise support bar)

[Rick62]

Hey guys,
I Recently purchased a rare (for Australia) 1994 26S classic.
I am wanting to fabricate a gin pole for raising my mast on my 26S classic. I am assuming it is alloy ? I need to know the dimensions. (prefer metric) length, circumference, and wall thickness. Also where can I get the foot brackets from? or what would be an alternative to modify. Would like to do it by the weekend so ordering from the States not an option. Not sure to use the purchase system or the winch with a brake system as on the current shape boats. My boat all ready has fixed baby stays as well so the set up should be relative easy.
Also... The previous owner has threaded a new centerboard cable through the well, however has not had time to fix the broken cable to the centerboard. Is this possible to replace in shallow water with a bit of snorkeling gear and a spanner rather than try to lift the boat of the trailer and hardstand it?
I have also noticed very small black dots in the anti skid section. Not sure if this is mold or thin gel coat which is deteriorating with age.
Cheers
Rick

[chapster5]

I got my self a length of aluminum c channel ( nice and light) that I use and I keep this mounted on the side of my trailer. Since I only raise and lower the mast while its on the trailer at the ramp this seems to work well for me. If you like I can get you a length measurement next time I am at the club ( yes still waiting for snow to melt but we are getting closer ).

Just a cheap option.

good luck, Chapster5

[Tomfoolery]

The and MRS uses a 1-1/2" X 1/8" wall x 6 ft long aluminium tube. The bottom is attached with a pair of 'pole straps', BWY p/n 3423-1V0, but you can make your own if time is of the essence. They pin to the mast tabernacle, but many folks who've made their own pin it to the mast itself, near the bottom, but high enough to not fowl with the deck.

The pole has a pair of eye straps for attaching the jib halyard on one side, and the fiddle block on the other. Be sure to through-bolt these, as you don't want to pull the tube apart by bolting them only to the tube wall itself. That way most of the force is simply transmitted from one eye strap to the other through the bolts, and the only load to the pole itself is compression via shear at the bolts. Use nylon lock nuts ('aircraft' nuts), as them coming loose when you're using it can kill someone.

The system is similar, but with a single sheave block attached to the mast side eye strap, and a brake winch 3/4 of the way up the pole. The OEM system uses a Dutton-Lainson brake winch. DON'T use a conventional ratchet winch instead, because if you lose the handle going down, there's no stopping it, and you'll bust your knuckles or worse trying. The type MRS needs a bail on the mast to connect the line to.

Between the two, the system is easiest and cheapest to make if you're in a hurry, as you use the boom vang or some other pair of blocks (I'm using a 5:1 system with ball bearing blocks I had laying around), which are already on the boat. But the system is probably easier to use, and if I was going to actually build one from scratch, I'd make that one.

Oh, and for the pole, you can use 1-1/4" EMT (Electrical Metallic Tubing, 1.51" OD x .065" wall galvanized steel electrical conduit). It's heavier than the aluminium, though about half the wall thickness, and you should sleeve the tube where the bolts go through because the wall is so thin, but it's super cheap, readily available, and has a buckling strength in that length that's as much or more than the aluminium even though the wall is thinner.

[kmclemore]

!	kmclemore:
	Rick, I'm sorry but we don't allow posting the same thing in multiple threads. The forum would become a real mess if we did. I've merged all your posts and replies here in the Mac/Venture forum as it seems that's where it belongs based upon the type of boat.

[Rick62]

Thank you "Tomfoolery" for your very descriptive response. Exactly what I needed.
I find raising the mast (with headsail and furler) not too big an issue but certainly requires some effort. Its when the mast
is coming down that I find it more difficult and tends to want to get away from me. I am very weary of trying not to walk on the coach roof hatch as I'm not sure if its strong enough. I will be off to metal world today to buy my pole.
Thank you once again for the effort you put into your response.
Rick

[Tomfoolery]

I believe the OEM is 6061 aluminium tube (tube, not pipe), in case you want aluminium instead of steel.

[Rick62]

Thank you once again.
I hope they have this in stock.
Cheers.

[Rick62]

Well bought and put everything together. I am using the main blocks at the moment. Works a treat.
Just one question…How strong is the forward cleat that attaches to the main block? Seems to be a lot of strain on it in the initial raise until the angle gets acute.

[Tomfoolery]

From your description, it sounds like you made the system, using the fiddle blocks from the mainsheet system. Depending on the weight of the mast and sail, the load on that forward strap eye approaches 350 lb, and more (considerably) with impact loading, like bouncing the mast as you lower it.

Hopefully, you used through-bolts from one strap eye to the other, so the part of the load along the bolt axis is simply carried from one side to the other, and isn't trying to pull the tube apart. The eye straps are a lot stronger than you might think, though without knowing what exactly you used, it's impossible to know how strong they are (and many aren't load-rated anyway), but most eye straps will distort badly (and permanently) long before they let go.

This came from a quickie analysis I did a while back to see what the magnitude of forces in the MRS are. Those are static loads (no bouncing), but on the conservative side, with a 150 lb mast, furler, and large head sail. The 275 lb force is on the halyard, and the 350 lb force is to the deck attachment point. The winch on the version is, not coincidentally, 350 lb rated.