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Broken sail track on boom

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Created by Skipper58 3 months ago, 27 Aug 2025
Skipper58
NSW, 34 posts
27 Aug 2025 7:45AM
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After some of the strong blows in recent months, I have noticed that the leading slide (nearest the mast) has lifted clear of the track. Upon investigation my boom has an aluminium extrusion inserted along the slot on the boom to narrow the slot for sail slugs to be retained on the boom. The forward 25 -30 cm has broken away and disappeared so the slug now floats free. For context the main and sail bag with lazy jacks are secured to the boom by these slugs. Does anyone have any suggestions of who or how this might be repaired?


r13
NSW, 1712 posts
27 Aug 2025 8:35AM
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What yacht model is it on and who manufactured the boom? The oem should have a replacement extrusion?

If in Sydney suggest try www.infinityrigging.com/ or Sheerline Yacht Masts 02 9938 4722

Skipper58
NSW, 34 posts
27 Aug 2025 1:07PM
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Select to expand quote
r13 said..
What yacht model is it on and who manufactured the boom? The oem should have a replacement extrusion.


The yacht is a Carter 30. Boom manufacturer is unknown at this time.

FabulousPhill
VIC, 320 posts
27 Aug 2025 4:34PM
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You could photograph the profile from the left-hand side of the above area, to show the profile.
A replacement profile could be riveted in.

r13
NSW, 1712 posts
27 Aug 2025 4:54PM
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Vulcan Ullrich could have the extrusion - need to measure it up carefully and do a cross section schematic as well as a photo

vulcan.co/product/aluminium/#au-aluminium-product-guide

Capral could have it -

www.capral.com.au/extrusion-plate-sheet/extrusion/

The photos are a tad difficult to interpret but the "breakage plane" seems reasonably clean - and the two empty holes in the boom proper may be a bit telling - is the broken away piece a separate 25-30cm long piece from the rest of the extrusion?

Skipper58
NSW, 34 posts
27 Aug 2025 9:17PM
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Select to expand quote

The photos are a tad difficult to interpret but the "breakage plane" seems reasonably clean - and the two empty holes in the boom proper may be a bit telling - is the broken away piece a separate 25-30cm long piece from the rest of the extrusion?


I don't believe it was a separate piece. The breakage point is fairly straight but not really smooth. Getting in to get an accurate profile should be fun!!

My guess is that the extrusion will need to be slid off the boom. I expect that will not be an easy exercise.

FabulousPhill
VIC, 320 posts
27 Aug 2025 9:45PM
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Skipper58 said..
My guess is that the extrusion will need to be slid off the boom. I expect that will not be an easy exercise.


I'd rivet something over the top of the boom, i.e. not inside but on top. No one's going to see the mismatch.
One other thing: the remaining slugs will give an idea of the profile.
Bunnings has aluminium profiles, but not marine-grade material.

Ramona
NSW, 7722 posts
28 Aug 2025 8:16AM
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I agree with the riveting a section to fix. If it was me I would cut up two pieces of aluminium and rivet and glue with JB-Weld. Put a piece either side to make it look like a "special" reinforcing and not just a repair.

Skipper58
NSW, 34 posts
28 Aug 2025 9:38AM
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Select to expand quote
Ramona said..
I agree with the riveting a section to fix. If it was me I would cut up two pieces of aluminium and rivet and glue with JB-Weld. Put a piece either side to make it look like a "special" reinforcing and not just a repair.


Interesting ideas and a lot easier than removing the whole extrusion. Thanks for the input. I think a curved extrusion that follows the curve of the boom would look best and have the most surface area for gluing.

MAGNESIUM
218 posts
28 Aug 2025 3:00PM
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Select to expand quote
Ramona said..
I agree with the riveting a section to fix. If it was me I would cut up two pieces of aluminium and rivet and glue with JB-Weld. Put a piece either side to make it look like a "special" reinforcing and not just a repair.


Romona are you saying the two pieces riveted to make a slide for the slugs to go into?

Skipper58
NSW, 34 posts
28 Aug 2025 6:25PM
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Select to expand quote
MAGNESIUM said..

Ramona said..
I agree with the riveting a section to fix. If it was me I would cut up two pieces of aluminium and rivet and glue with JB-Weld. Put a piece either side to make it look like a "special" reinforcing and not just a repair.



Romona are you saying the two pieces riveted to make a slide for the slugs to go into?


It is a good question. I believe that is what he is saying. My question is what sort of loads (vertical and lateral) are on the sail slugs from the main and sail bag?

JonE
VIC, 536 posts
28 Aug 2025 6:48PM
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My question is what sort of loads (vertical and lateral) are on the sail slugs from the main and sail bag?


Obviously sufficient to rip that bit of track off.

woko
NSW, 1745 posts
28 Aug 2025 8:00PM
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If it was me I would be done with the sail slug & stitch a webbing loop in its place. From what I can see the sail cover looks a bit diy, and it's possible that it was originally not a perfect fit

longwinded
WA, 347 posts
28 Aug 2025 6:08PM
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Don't just look at the repair. It is an unusual place to fail. I would be looking at main halyard tensions, pre-setting the Cunningham to achieve those halyard tensions and anything else that could put a load on that part of the mainsail.
Of course you will need to repair it, but making it not happen again is also important.

Skipper58
NSW, 34 posts
29 Aug 2025 10:03AM
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It happened while sitting on the mooring, with mainsail down and sail bag zipped up. Main halyard only tight enough to keep line taut.

I was not present but my guess is very strong wind gusts, putting a lateral and slightly upwards pressure on the slugs.

Ramona
NSW, 7722 posts
29 Aug 2025 6:05PM
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Select to expand quote
MAGNESIUM said..

Ramona said..
I agree with the riveting a section to fix. If it was me I would cut up two pieces of aluminium and rivet and glue with JB-Weld. Put a piece either side to make it look like a "special" reinforcing and not just a repair.



Romona are you saying the two pieces riveted to make a slide for the slugs to go into?


I would use two pieces of 3mm aluminium. Bend each piece so it blends in with the curve of the boom. The top edge where it contacts the slugs round off the edge. It would end up similar to my slug cassette on my mast that holds the slugs captive when the sails down. This being on the boom where the slugs rarely slide along does not need to be faired in but if required, JB Weld is ideal.



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"Broken sail track on boom" started by Skipper58