Thread: Running Rigging for the Goat

Originally Posted by Compass Project

MAM,
Did you look into what a mast would cost to have made for you? If not, and it is not to late, please do it. You may regret this mast/flagpole idea as it doesn't fit the Goat. I would cancel the order and give a boatbuilder nearby a call and have them make one for you, or feel free to email me in private. I would be more than happy to help you find a builder down there to get you a better mast option.

If I can help, feel free to contact me.
Best,
Clint

Howdy

Another nice way might be to get some birdsmouth staves made up at a boatshop .. which is the quick side of things .. but hard to do if you don't have the right equipment - but a reasonably quick thing to do if you are set up.

They would also be compact to ship. On arrival they could be tapered and glued up.

One of the nice things about birdsmouth is that it does reduce the labour of the mast rounding quite substantially.

I would prefer a wooden mast in the boat ... but it is MAM's boat 110% so he has to work out what suits him. You will make sure the mast floats though Archie?

I would suggest getting a plug turned up for hte base or cutting a piece of melamine or plastic chopping board to drop in the step to distribute the load of the alloy edge.

Happily too .. the mast is completely separate so if there is a decision to change later it is not difficult. If the alloy mast is chosen for the moment it is possible to move to a wooden one later if desired. The step could remain the same and bottom of the wooden mast stepped down to fit and the partner could be cut out to the wood mast spec and resealed.

Best wishes
Michael

The question about Harken ratchet blocks and swivelling.

Sorry I could have answered earlier, forgot.

The Harken 57mm carbo ratchmatic is my favourite block in all the world. It's just such a great help and I know MIK does not approve of expensive blocks, but this block is business for handling a large lug mainsail without strain.

I have recommended it to a number of fellow sailors with joint problems in their elbows and shoulders and they are always really pleased they fitted it. Ronstan also do a similar block and I have spoken to some boat builders who reckon they are longer lasting.

http://www.harkenstore.com/uniface.u...?409Z56LC7VPMA



You can see the swivel post at the top of the block.

Brian

I wouldn't dream of just setting the hard tube end down in the mast step. I intend to seal both ends of the mast with wooden plugs/caps. The holes for fastening the halyard cleat should be air and water-tight as well, with the fasteners set in either 5200 or epoxy. So I have little doubt she'll float but I'll test it. I'm thinking it might float tip-down if just tossed in the river but the wooden yard should keep it from turning turtle.

I have a choice about which end to cut (it's 17 feet long) but I'll probably take some off both ends. If it's anything like the ones I used on my Gazelle there will be a heavy alloy casting at the top which will need to be removed, not only for weight saving but to allow insertion of a wood plug so the halyard dead-eye bolts have something solid to pass through.

I don't recall which Harken ratchet I ordered but it's the same size as the one pictured above. The price was about $50 Canadian, $45 US dollars.

Edit--it's the Harken Little Hexaratchet, 2 1/4" sheaves, number 019 on this page:
http://www.harkenstore.com/uniface.u...=409Z56LC5373M

Working load and breaking strength are the same as the Carbo above but it appears to be an older design.

Howdy Archie,

If the there is no taper in the bottom third and it doesn't seem very flexible - when you cut it I would take most of it off the bottom end.

Check flexibility by putting between two chairs and sitting on it.

But if the top is excessively tapered I would trim the top so it is about the same diameter as the top of the wood mast.

MIK

Good point about the diameter at the top, MIK. I wasn't worried about the strength but all this talk about flotation puts me in mind to keep the top diameter as large as possible for better bouyancy. I believe the mast is straight for the first 5 or 6 feet and then it tapers down to either 1 1/2 or 1 7/8...I'll have to check the specs. That's not too much different from the solid Oregon spar IIRC.

Shoot, for maximum bouyancy where it counts maybe I should put it in upside down with the 3" butt at the top! jk

As for sitting on it, how much deflection is a lot and how much is a little with, oh, say 230 pounds plunked down in the middle?

Howdy MAM,

You get a lot of buoyancy from the yard anyhow, as long as the mast doesn't fill to counteract the good intentions I think to match the tip diameter of the wood mast will work the best aesthetically.

MIK

I've concluded I can take the excess length from the top and end up with something close to the original solid wood stick. It's tapered to 1 7/8 inches so taking 19 inches from the top will give me roughly 50mm for the final diameter at the top. This means I've reduced the tapered section from 75 inches to 56 inches. The bottom, untapered portion, will be 129 inches. The bare pole will be cut to 185 inches with wood caps/plugs at top and bottom bringing it to 186 1/4 inches overall, or 4730mm.

All this is subject to change once I have had a chance to check the flexibility of the pole but I'm leaning heavily toward doing it this way because it will provide the most flotation possible for the aluminum pole. I plan to cap it at the top with 1 inch of wood with a heavy taper and solid plug under. At the bottom I'll plug it leaving about 1/4 inch of wood exposed so that the base of the pole is well within the step. If I find the mast tends to rotate in use I'll have to come up with a way to lock it in place. I won't worry about it until I see if it's a problem or not.

Howdy MAM,

The amount of buoyancy is not much at all.

I would use the stiffness and aesthetics of the spar as the main criteria.

If you sling it between 2 chairs and it seems quite stiff when you lean or sit on it then I would aim at a top taper diameter similar to the original wooden mast.

But if it seems very flexible ... I would go for your plan above.

as far as the base plug goes - there does not need to be a lot there particularly if you make it of two layers of 19mm timber glued together with their grain at 90 degrees so there cannot be any splitting.

I would glue and use fastenings

For glue to work any anodising will have to be removed from inside the mast. Nothing sticks to anodising.

Use the WEST method for bonding to metal - put mixed resin/hardener on the surface, don some good gloves and wet sand the metal using the epoxy as the wetting agent - and then make add the glue powder and glue the plug in place. This ensures you are bonding to metal rather than the metal oxide which forms on the surface very quickly.

Use four metal threads (type you normally put a nut on) as bigger diameter as possible without the countersunk head protruding - if they are 25mm (an inch) long that will be fine. You will need four.

Michael

I understand about the flex; the difference in diameter at the top will only be about 1/8 inch whether I cut from top or bottom. I hear what you're saying about buoyancy--that 1/8 inch won't make much difference there either. So flex test it will be.

As for the plugs top and bottom, my first inclination was to put them in with 5200 which sticks to just about anything. Getting them out would be more difficult, though. I would probably have to destroy them to remove them if that is ever needed. I'm glad you mentioned a solid wood plug for the bottom in two 3/4 inch layers. I hadn't thought of the possibility of the single plug splitting so I will certainly do it as you suggest--two layers glued with the grain at 90 degrees. I will need at least as much wood inside the top as I leave exposed so that will be three layers with the grain alternated in each.

Do you see any problem putting the plugs in with 5200 as opposed to epoxy, other than the fact that I have epoxy on hand and would have to buy a tube of 5200?

I'm not sure I understand about the screws--are you saying I should secure the wood plugs with machine screws instead of wood or tapping screws? Since I planned on having a shoulder on the bottom cap (sticking out 1/4 inch past the aluminum) the plug could not wander up inside so I'm not sure what the machine screws are for...

Howdy MAM,

If the machine screws are glued in with epoxy they will help transfer the load into the metal even if the shoulder at the base breaks away a bit - which it probably will do because of grain direction. This is the standard method used with plastic and aluminium mast bases too..

The 5200 ... I don't know if it will be strong enough in terms of transferring load.

WEST have found that machine screws that are glued in are much less likely to lose their heads than any other alternative.

Just tossing ideas ... hoping that we can get a better solution together than individually.

Michael

I got the bare flagpole and opened the carton this evening and removed all of the protective packaging. I've got it resting on two bar stools where I did a preliminary flex test. It seems to flex a couple inches with maybe 1/3rd of my weight on it, say 75 pounds. Everything is guesstimated at this point and I plan to suspend containers of water from the center to better quantify the flex.

The big surprise came when I weighed the full length pole (17 feet). According to my fairly accurate bathroom scales it weighs 21.8 pounds! The first time I weighed it I set the scales near the middle and weighed myself, then stepped off the scales, picked up the pole and stepped back on the scales. The difference was 21.8 pounds. I was very suspicious of this number so I positioned the scale where I could stand the pole up in my living room. With the pole nearly vertical (it was leaning slightly on an upstairs banister) the reading was 20 pounds so I think I can trust the initial figure. By my calculations the bare pole will weigh in right at 20 pounds before I add the caps/plugs top and bottom and the two pieces of hardware...maybe 21 pounds when all is said and done. I will probably paint it (it isn't anodized) so it might end up closer to 22.

This is about 10 pounds less than what I figure the solid Oregon spar weighs and within a pound or two of the hollow spar.

Deflection with about 32 pounds of water was about 12mm. Looking back at the deflection tests I did on the boom and yard, at the request of the sailmaker, this seems to be about what might be expected with the Goat's solid wood mast. (The boom and yard deflected 43mm and 40mm respectively with this same weight.)

Aesthetically the mast will look better if I retain all of the taper at the top and take my 19 inches off the base. There is no weldment or casting at the top as there was in the larger poles I used on the Gazelle so the only reason to cut the top would be to increase the diameter from 1 7/8" to 2". I would have to cut about a foot to accomplish that so I think I'll opt to leave it alone.

Once I cut the 19 inch section from the bottom I plan to seal the ends of the off-cut and toss it in the kitchen sink. I have little doubt it will float just fine. My koi pond is a couple feet too small to test the finished mast, though, so a test of the that will require that I take it down to a nearby creek.

With much trepidation I cut 18 1/4 inches from the base of the aluminum stick. It's now the right length to finish out at 15' 6 1/4" once I add the external wood caps at each end. I carefully weighed it and it is exactly 19 pounds so it should finish a little under 21 pounds with the plugs, caps, hardware and paint.

The flotation test for the off-cut went swimmingly. I closed it up with Saran Wrap and rubber bands and it floated with about 2/5 of the diameter immersed, 3/5 above the water. The tip will be a little heavier for its volume but it should float just fine, especially with the yard attached.

I've simplified and improved the cap-plug design, adding "lightness" as a plus. Instead of two layers of solid wood I will have a single 3/4" layer sandwiched between two layers of 6mm okoume. I'm pretty sure the plywood will take the crushing forces at the base better than solid wood. I still haven't decided whether to put them in with epoxy or with 5200. I believe the 5200 with be a better sealant and will be more forgiving of fit so I'm leaning toward that. With epoxy bonding the three components of the sandwiched plugs/caps together, the only stress I can envision will be from the mast heating up and, assuming it is truly air tight, the hot air will be trying to push the plugs out. 5200 should be able to handle that sort of force without problems. There are a couple things I can do to minimize this--do the final closing-up on a warm day out in the sun. I could also drill a tiny hole just above the base so it's not air tight but will still be water tight where it counts.

Howdy. The ply will take the forces that will tend to split timber too ... so a much better solution.

MIK