Re-stepping the mast - spreader angles?

[TyroSailor]

Evening, all.

At long last my Centaur is back in the water (New readers see http://www.westerly-owners.co.uk/woafor ... 425#p15425 and http://www.westerly-owners.co.uk/woafor ... f=2&t=3636 and maybe even as far back as http://www.westerly-owners.co.uk/woafor ... f=2&t=3255) and I'm intending to ressurect the mast with its new rigging next month.
What I want to know is: how do I set the spreaders at the correct angle? It seems to me that there are four options:

1. Mount them horizontally on the mast using sealant or similar in the sockets - this is how they were before and I've seen many other boats (including Centaurs) like this
2. Discover the correct angle by measuring another boat or asking somebody who knows, such as the distinguished readers of this forum - or Paul at XW Rigging and set them in sealant or similar at this angle
3. Fill the sockets with sealant and shove the spreaders in immediately before raising the mast then push them into the correct position with a long boathook once the shrouds are connected but before the sealant sets.
4. The correct method which one of you experts is about to reveal

[Jolly Roger]

Steve

The spreader should be slightly above horizontal to equally divide the angle between the upper part of the cap shroud and the lower part.

Check the spreader bases as they may already have a slight angle built into them. Check by inserting the spreaders and tying a light line across from the outer ends. If it lines up with the bases then the spreaders are definitely horizontal. If it is above the spreaders then they are angled.

Personally I am not keen on filling the spreader bases with mastic as you will probably will never be able to remove them. There might be a little fit in the spreader bases, but generally I would raise the mast and start tensioning the rigging. Walk/row some distance away to see how they sit. If they are slightly low then push them up with a length of timber. Finish tensioning the rigging and go sailing for some hours with a reasonable breeze. Recheck your rigging tension and the angle of the spreaders.

Hope every thing goes smoothly and you can soon hang those white things out to catch the breeze.

[TyroSailor]

Thanks Roger.

They were certainly horizontal before (as are all the other Centaurs I've seen), but I fully understand the desirability of cocking them up to bisect the shroud angle. They were also mounted in mastic of some kind which had crumbled over the years. Without it they'd be a very loose fit in the sockets (although they were held in by vertcal bolts). Someone suggested coating them in clingfilm before putting the mastic in so it doesn't stick to them.

(Someone else, on another forum, pointed out that it's only a Centaur!)

[Jolly Roger]

Steve

I am very anti using a mastic in the spreader ends. If the spreader is loose in the socket I would use electrical tape to reduce the movement. You could also adjust the angle by using the tape to add extra layers of tape as packing.

[TyroSailor]

That's a thought. It'd need several layers though. And it means going up the mast to do it. What sort of tape would withstand wind and weather?

The only photo I can find of the sockets does show them pointing slightly upwards.....let's see if I can upload it.....

DSCN3697_opt(1).jpg (84.61 KiB) Viewed 3499 times

There we go. Web resizer to the rescue again. It looks like the sockets may be correctly angled but the spreaders weren't. (This was shortly after the mast was lowered in 2015!)

[Jolly Roger]

Steve

The bases are definitely angled. It looks as if the fit is very generous and allows the spreaders to be able to be level. Maybe because it is a Centaur that most owners think they should be level.

It is a simple job to pack with electical insulating tape. I would suggest two bands, one at each end of the spreader where the socket bears. The alternative would be to use self almagamating tape, but this may deform slightly more.

[Gary-Cottam]

Instead of tape, mine has some kind of plastic pipe holding them secure at what I presume is the correct angle.

Hopefully, I'll be at the boat this weekend and can take a picture to clarify.

Gary

[TyroSailor]

That would be really useful Gary

[aquaplane]

The spreader should be slightly above horizontal to equally divide the angle between the upper part of the cap shroud and the lower part.

That's what I thought was the optimal set up too.

In reality with a Centaur it could be anywhere between horizontal and the optimal, it probably doesn't matter much so long as it's somewhere near.

[Jolly Roger]

Bob, I do not disagree with your comment. The loading is well within the the strength of the spreader, but it will always be best to set the correct spreader angle.

[aquaplane]

Also, how are you going to measure the angle, and how accurate will it be?

Stick the spreaders in the socket, throw the mast up and have a look, if they are even it's going to be right.

Let's face it, how are you going to adjust them if they don't look as pretty as you would like?

It's good the boat is floating, that is important.

[Jolly Roger]

Also, how are you going to measure the angle, and how accurate will it be?

The most accurate way of getting the correct angle is the Mk 1 eyeball. This is a surprising accurate device that can assess how similar the two angles are.

Another method is to photograph the ends of the spreaders from some distance from eirther ahead or astern and then print off the image and use a protractor to compare the angles.

Both methods will give an accurate enough bisection of the angle of the spreader on the cap shroud.

[TyroSailor]

That was the technique I had in mind, Roger. The MkI eyeball is an amazing bit of kit, and costs nothing to buy or maintain. Until the internals start to break down after many years of daily use.

If I'm going up the mast anyway I can take a protractor with me though. I wonder how long insulating tape would last?

[Gary-Cottam]

It is strange how the fittings are oversized compared to the spreaders themselves, you would have thought the manufacturers would have come up with something better.

As promised here are pictures of the spreaders on Gemini:

http://www.westerly-centaur.co.uk/spreaders

Looks like some sort of hose pipe has been used as padding, probably easier and more than resilient than tape, but still a very clunky solution.

Unless anyone has a more elegant solution, I will probably just replace the hose pipe with something newer.

Gary.

[philipstevens]

Depending on how much space between socket and spreader, try a piece of plumbing plastic waste pipe in the gap. You can always slice the pipe to fit.