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Spreader Brackets Question

Pingpro

New Member
Hi everyone,

I am new to j/24's and a fairly new sailor and have never rigged a sailboat before. Been working on hull 3205 for a while now and I am getting close to splashing and have the mast out to rig before heading to a boatyard. I think I have a lot of it figured out but I have two masts that the previous owner gave me. One short for stepping it on the deck and a full mast. I plan to use the full one but he was using the short one.

The spreader brackets he was using are on the short mast so I need to move them. They seem to be pointing a little towards the deck. (See pic, though you can't really tell they are pointing slightly down, the top of the mast is to the left). I know that you want the angle of the stay entering and exiting the spreader to be the same. On a j/24, would this mean that the spreaders would point a little downward? I just assumed they'd point upward but given the beam of the boat and location of the chain plates, maybe I am wrong.

Finally, in the picture showing the spreader, the existing hole through the spreader and spreader bracket align so that the spreader isn't against the mast, it sits out about a half inch. Is that normal?

Many thanks as always,
Christian
65004145616__7E11C72A-A8EA-4099-B182-CCF55501AAE9.jpgIMG_8272.jpg
 

VinceH

Member
The spreaders should project slightly upward, so as to bisect the angle formed as the shroud goes over the spreader tip. Alternate explanation is that the angle between the spreader and upper half of the shroud should be the same as the angle between the spreader and lower half of the shroud. So I think those spreader brackets are on the wrong side of the old mast.

We don't know if you're just trying to get a setup to go sailing, or if you are looking to race the boat, and therefore optimize it. The advice you'll find is aimed at optimizing things for racing.

For the past 20+ years the standard has been to use a spreader 'thru-bar' that you can see here, together with the plates that go over it. It's bent to give the desired sweep and upward angle: J/24 Spreader Thru-Bar Kit — Waterline Systems. Here's installation instructions that may also be helpful to you: Instruction Sheet - J/24 - Installing K-11867K Spreader Bar Kit

The North Sails Tuning guide J/24 Tuning Guide | North Sails gives a comprehensive explanation of how to set things up. If you're just going sailing, you don't need to stress about exact angles or dimensions, but for racing that setup has been the standard for a long time. They talk in there about their "Fathead Main". That's pretty much a regular main, similar to what Quantum or others would supply. If your spreaders are, or can be 760mm long, as recommended, you do want them to bear against the mast and not be simply held in place by the screws. You really want them to bear against the mast rather then try to shear off the screws.

When you rivet the plates in place, you should use an anti-corrosive paste, like tef-gel. Very important! Any place stainless steel and aluminum come together you'll have serious corrosion of the aluminum over time without it. A little syringe will last you a long time.

Lastly, the deck-stepped mast idea is totally non-standard, and I'd be suspicious that it could cause problems. The deck wasn't designed to take loads like that. It's a lot when the shrouds are cranked-up tight. Maybe it's ok, but we sure don't know.

-V
 

Pingpro

New Member
The spreaders should project slightly upward, so as to bisect the angle formed as the shroud goes over the spreader tip. Alternate explanation is that the angle between the spreader and upper half of the shroud should be the same as the angle between the spreader and lower half of the shroud. So I think those spreader brackets are on the wrong side of the old mast.

We don't know if you're just trying to get a setup to go sailing, or if you are looking to race the boat, and therefore optimize it. The advice you'll find is aimed at optimizing things for racing.

For the past 20+ years the standard has been to use a spreader 'thru-bar' that you can see here, together with the plates that go over it. It's bent to give the desired sweep and upward angle: J/24 Spreader Thru-Bar Kit — Waterline Systems. Here's installation instructions that may also be helpful to you: Instruction Sheet - J/24 - Installing K-11867K Spreader Bar Kit

The North Sails Tuning guide J/24 Tuning Guide | North Sails gives a comprehensive explanation of how to set things up. If you're just going sailing, you don't need to stress about exact angles or dimensions, but for racing that setup has been the standard for a long time. They talk in there about their "Fathead Main". That's pretty much a regular main, similar to what Quantum or others would supply. If your spreaders are, or can be 760mm long, as recommended, you do want them to bear against the mast and not be simply held in place by the screws. You really want them to bear against the mast rather then try to shear off the screws.

When you rivet the plates in place, you should use an anti-corrosive paste, like tef-gel. Very important! Any place stainless steel and aluminum come together you'll have serious corrosion of the aluminum over time without it. A little syringe will last you a long time.

Lastly, the deck-stepped mast idea is totally non-standard, and I'd be suspicious that it could cause problems. The deck wasn't designed to take loads like that. It's a lot when the shrouds are cranked-up tight. Maybe it's ok, but we sure don't know.

-V
Thank you Vince for all the information, it is greatly needed and appreciated.
I am starting to realize that the way the previous owner had the boat set up, may not have been very traditional. When I find info online and compare it to what I see, some things don't match. For example, the Jib and Spin halyards exit the mast on the port side. I think you posted that they're supposed to exit on the starboard side?
I am setting the boat up for sailing with friends and family and don't plan to race for at least a year, so I will go with my current spreader set up until the next haul out. I just want to get out there and get some experience for now.
As far as the deck stepped mast, I think he designed and built the entire set up. It was what he used the most and I did have to replace a big soft spot directly port of the mast. Not sure if it was related (probably a poorly filled hole).
I'll follow your advice and may have more questions.
Again, thanks for taking the time to respond.
-Christian
 

VinceH

Member
You're welcome. Just keep in mind the advice about having the spreader push against the mast rather than the screws. If it should fail in a good breeze, you could lose your mast. That's expensive.

Jib and Spinnaker halyards exit on the starboard side because when racing it's normal that the marks are left to port. So coming into a windward mark you're on Starboard and ease the main as you round. The Stbd side of the boat is to windward and the boom is opposite, so there's room to work to raise the spinnaker and lower the jib if they're on starboard.
 

Pingpro

New Member
You're welcome. Just keep in mind the advice about having the spreader push against the mast rather than the screws. If it should fail in a good breeze, you could lose your mast. That's expensive.

Jib and Spinnaker halyards exit on the starboard side because when racing it's normal that the marks are left to port. So coming into a windward mark you're on Starboard and ease the main as you round. The Stbd side of the boat is to windward and the boom is opposite, so there's room to work to raise the spinnaker and lower the jib if they're on starboard.
Will do. If the mast goes down, it's part out time.... Also, great explanation of why certain halyards exit where they do. I do think that the deck is set up for the way the mast is set up. Gonna set it up this week, take it to a yard and splash next week then 81 nautical mile sail / motor to the slip. Will take a couple days as there isn't much wind in Naples this time of year.

Last things... when I attach the spreader to the bracket and re-drill the hole, it seems that I'll need shims or something as it's not a tight fit. Is there something I should use? Also, if I bought the through mast one piece spreader, how do the stays attach to it? There doesn't seem to be anything included by shoreline for that.

Many Thanks,
Christian
 

VinceH

Member
Christian! Noo..ooo! You don't want to part it out after all your effort. I don't remember in detail how they were originally rigged, but yes, there were turning blocks 'foot blocks' on the deck to lead lines back to the cockpit. In 1978 it was all the rage to have everything led to the cockpit. With the halyards exiting on the starboard side of the mast as is the custom now, there is normally one cam cleat for the spin halyard which exits above head-high, for ease of hoisting (several big yanks downward does it). The jib/ genoa halyard exits lower... a couple feet above the boom, and has two cam cleats in series to handle the high halyard tension. Then goes through a ratchet turning block adjacent to the mast on the deck. So this one is pulled upward, finishing with your legs to get it very tight (when needed).

The spreaders slide over the tangs protruding from your brackets, of course. They (spreaders) ideally should be shaped at the inboard end with a file so that they match the curve of the mast and butt up tightly against it. Any slop you have then is just due to tolerances (poor fit) between the inside of the spreader and the tang on your bracket. Maybe those old-style ones aren't as close tolerance as the newer 'thru-bar' setup. The thru-bar that you see in this kit ...
1628544534337.png
just provides something upon which to mount the spreaders. It's not the spreaders. You mount the spreaders onto the bar. They slide over it, as you do with your current bracket. I think the fit is reasonably tight, as I recall, but there's still a little slop. When you tighten the shrouds, all that slop will go away and the spreaders will be angled as far aft as the fittings will allow, if that all makes sense. If you buy new spreaders at ~$135 each, you need an end-piece too.
From Rigright.com:
1628544791769.png
 

Pingpro

New Member
Christian! Noo..ooo! You don't want to part it out after all your effort. I don't remember in detail how they were originally rigged, but yes, there were turning blocks 'foot blocks' on the deck to lead lines back to the cockpit. In 1978 it was all the rage to have everything led to the cockpit. With the halyards exiting on the starboard side of the mast as is the custom now, there is normally one cam cleat for the spin halyard which exits above head-high, for ease of hoisting (several big yanks downward does it). The jib/ genoa halyard exits lower... a couple feet above the boom, and has two cam cleats in series to handle the high halyard tension. Then goes through a ratchet turning block adjacent to the mast on the deck. So this one is pulled upward, finishing with your legs to get it very tight (when needed).

The spreaders slide over the tangs protruding from your brackets, of course. They (spreaders) ideally should be shaped at the inboard end with a file so that they match the curve of the mast and butt up tightly against it. Any slop you have then is just due to tolerances (poor fit) between the inside of the spreader and the tang on your bracket. Maybe those old-style ones aren't as close tolerance as the newer 'thru-bar' setup. The thru-bar that you see in this kit ...
View attachment 47669
just provides something upon which to mount the spreaders. It's not the spreaders. You mount the spreaders onto the bar. They slide over it, as you do with your current bracket. I think the fit is reasonably tight, as I recall, but there's still a little slop. When you tighten the shrouds, all that slop will go away and the spreaders will be angled as far aft as the fittings will allow, if that all makes sense. If you buy new spreaders at ~$135 each, you need an end-piece too.
From Rigright.com:
View attachment 47670
OK, OK.. I won't part it out. Ha. I should have realized that the one piece spreader bracket wasn't the actual size of the spreaders... I'm going to try and rig the mast and prepare it for stepping tomorrow and may have a question or two with photos to go along. I'm not planning to actually step the mast until I get to a boatyard next week. Just prepare. Also, I need to remove the the mast shaped piece that supported the deck stepped mast from the I rail (not sure if that's what it's called) in the bilge in the forward cabin (see pic). I think he took the newer mast he bought and cut it at the deck and fabricated aluminum to attach the now shorter mast to the deck. At least it wasn't unsupported. This is an old pic...
IMG_7531.jpg

Also, do I need a mast plate or boot? Previous owner never used one... I'm guessing yes :) If so, I need to order first thing in the morning.
p-1699-41031racing-plate1-300x300.jpg

Thanks,
Christian
 

VinceH

Member
Where ya gonna sleep, man, during your cruise? That looks like a mess! :)

I'm glad to see that the previous owner at least supported the deck. I don't understand his whole thinking. (I'm assuming it was a guy) Keep that short mast though. It will make a helluva gin-pole.

Do you at least have some sort of blocks to hold the mast in position at the partners (place where it passes through the deck)? You don't want it flopping around there. I'm sure that North Tuning Guide tells you how you should set the mast there. Even if you can't achieve what they say, it's good to understand what the goal is so you can come close. Not sure you need to purchase a mast boot, but would be good to have and you want something to keep water from going down there. You could get the job done with some plastic sheet and tape, for the short term. I'll show you what I have (it's not the bare minimum. Just for reference). It positions the mast at the partners where I want it, and provides a plate that covers the deck opening. When the mast is stepped, a piece of plywood, say 3 in. x 10 in. or so with a screw, holds the thing from under the deck so it won't think of popping out of the deck opening. A piece of white duct tape seals the 'plate' part against the opening in the deck, and a little bead of silicone seals the whole plug to the mast. I don't want water down there. I replaced the bulkhead twice and won't do it again.

I think if I were to make that thing today I'd use two layers of 3/4 in pvc trim board from Home Depot. Probably cheaper and easier to work and would work very well. Still use some higher-quality UV resistant piece for the top plate.
1628562690883.png

It's hard to imagine the prev. owner cutting a new mast. Mine cost $2500 in 2005. Price increases for all this hardware seem to be running well ahead of inflation for some reason. I hate to think of what a mast would cost now.

That "mast shaped piece" as you say, is indeed a piece of mast. Make sure you have the shoe that fits your mast and locates it on the I-beam, with some screws to hold it in place.

Assuming you've got things taken care of quite well, it will be a great trip. A life experience.
 
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