Forums > Windsurfing Foiling

Repair experts advice - ripped off mastbox (catapult)

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Created by Manilo > 9 months ago, 2 Feb 2025
Manilo
WA, 59 posts
2 Feb 2025 5:14AM
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Hi everyone

Yesterday 5 minutes after leaving the beach, foiling upwind I hit a fisherman's net (underwater), catapulted instantly and the mastbox ripped off the board.

Took me 30 minutes to get the net out of the foil. Then managed to unrig the sail in the water and tie up everything over the board, and swim back to the beach (1 hr 30').

Now I'm thinking how to get out the water that got in before repairing it. Cause it's in the middle of the board. For now I'm leaving it upside down, but I surely need a vacuum pump to be sure, don't you think? Thoughts?

Starboard Foil 100 (Y2021)






Subsonic
WA, 3354 posts
2 Feb 2025 7:19AM
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Stick it in the sun (in measured amounts, you might need to make a futher hole as it looks like the divinycell around the mast box is still there, that will block the water from leaching out. I'd probably lay the board flat and up the right way, as the boards rocker will make the mast track section somewhere close to being the lowest point. If you turn it upside down the water will probably migrate away from the hole.


now that its happened and you know the board ingested water, do away with the auto vent as well when you repair it. Install a normal one that you can remove after each sail.

jdfoils
433 posts
2 Feb 2025 9:23AM
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Wow, glad you were able to save the rig.
Definitely dry it out before repairing, the big hole in the deck will help

Mark _australia
WA, 23464 posts
2 Feb 2025 3:59PM
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That is foaming resin around the track. Is it cracked? If not and the track came out clean, it might have no water ingress

regardless, it needs a big block put in first so may as well do the router work and see if it drains

Manilo
WA, 59 posts
2 Feb 2025 9:50PM
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It's cracked....
Here are some photos.

Don't know if to glue with epoxi the divinicell and then sand to insert the box







thedoor
2470 posts
3 Feb 2025 2:50AM
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Just here to symphathize. Fishing net damn!

Did the mast track ripping out save the nose of your board? I guess I would rather do in the nose of my board than lose a mast track

Grantmac
2320 posts
3 Feb 2025 2:57AM
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I'd plan on routering out a rather large area to the depth of the old block, then installing one with a proper vent.

Manilo
WA, 59 posts
3 Feb 2025 3:02AM
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Select to expand quote
thedoor said..
Just here to symphathize. Fishing net damn!

Did the mast track ripping out save the nose of your board? I guess I would rather do in the nose of my board than lose a mast track


Yeah if I could choose I'd choose the same!!!
The nose has already some hits (who hasn't).

Looking at the bright side, the foil box and foil seem to be ok. Minor scratches to the wings.

A friend lost his new Patrik Aeon two weeks ago! (Forgot to put the 2 screws !!!!).
Today a swimmer found it, 100 m from the shore. Good luck for my friend (if I tell you it's the second he loses forgetting to put the screws you won't believe me.... But it is!)

Mark _australia
WA, 23464 posts
3 Feb 2025 11:45AM
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Ok now you have done all that poking it does leak.

as grant says, router action for a big block. But deeper, not same depth. The beige coloured stuff is rubbish. If you can't get thick PVC foam like divinycell and/or have not done repairs before, this is not a thing to do yourself sorry.

thedoor
2470 posts
3 Feb 2025 12:53PM
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Select to expand quote
Manilo said..

thedoor said..
Just here to symphathize. Fishing net damn!

Did the mast track ripping out save the nose of your board? I guess I would rather do in the nose of my board than lose a mast track



Yeah if I could choose I'd choose the same!!!
The nose has already some hits (who hasn't).

Looking at the bright side, the foil box and foil seem to be ok. Minor scratches to the wings.

A friend lost his new Patrik Aeon two weeks ago! (Forgot to put the 2 screws !!!!).
Today a swimmer found it, 100 m from the shore. Good luck for my friend (if I tell you it's the second he loses forgetting to put the screws you won't believe me.... But it is!)


Oh damn aren't those aeon foils 6000$?

Paducah
2787 posts
5 Feb 2025 10:04PM
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Manilo, were you, by chance, using a Surfbent, or similar type nose protector? Yes, that's going to be a challenging repair but doable.

Manilo
WA, 59 posts
8 Feb 2025 7:25AM
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Select to expand quote
Paducah said..
Manilo, were you, by chance, using a Surfbent, or similar type nose protector? Yes, that's going to be a challenging repair but doable.


Nope, I don't like them.
Seems the net stopped me instantly so I went forward hooked with all the rig... The duotone mastbase is really strong hahaha.....

Imax1
QLD, 4926 posts
9 Feb 2025 9:40AM
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Is it just me or the camera or does it look like the whole area including the glass seems to lack resin? Looks like the foaming resin didn't touch the sides of the hole. It looks too clean. By the look of the chunky glass around the box and the clean sides of the hole, how much gap was there , a quarter inch ? Foam should be stuck to the sides of the box as it rips out. Seems like the top lam was the only thing holding the box in. Dodgy ! Cobra needs to whip their workers harder. Or.... I'm wrong

boardsurfr
WA, 2454 posts
9 Feb 2025 5:48PM
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Select to expand quote
Imax1 said..
Is it just me or the camera or does it look like the whole area including the glass seems to lack resin? Looks like the foaming resin didn't touch the sides of the hole. It looks too clean. By the look of the chunky glass around the box and the clean sides of the hole, how much gap was there , a quarter inch ? Foam should be stuck to the sides of the box as it rips out. Seems like the top lam was the only thing holding the box in. Dodgy ! Cobra needs to whip their workers harder. Or.... I'm wrong


It's not just you. My first thought when seeing the pictures was that the break was way too clean, like the box never made contact on the sides at all. As if one worker did the routing and made the hole a bit too big, and someone else had a predefined amount of epoxy to put the insert in. But it's hard to tell from the pictures.

Mark _australia
WA, 23464 posts
9 Feb 2025 6:08PM
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No it's a wet out glass around the box and a foaming resin additive
it's not a slot routered into proper block. None of them are it's a ****ty install method that they simply need to stop using. It is barely sufficient with lots of top laminate .. But one layer of biax carbon over and a decent crash well here's the result.

Paducah
2787 posts
10 Feb 2025 10:06AM
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Is the issue the lack of adhesion between the glass wrap and the foaming epoxy the weak spot? Like the others, it looked like the glass hadn't been fully wetted out. That came out really cleanly.


Select to expand quote
Manilo said..

Paducah said..
Manilo, were you, by chance, using a Surfbent, or similar type nose protector? Yes, that's going to be a challenging repair but doable.



Nope, I don't like them.
Seems the net stopped me instantly so I went forward hooked with all the rig... The duotone mastbase is really strong hahaha.....



I don't either. Only time I saw a box come that cleanly out, some type of "nose protector" was involved.

jdfoils
433 posts
11 Feb 2025 2:04AM
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The foaming epoxy has very poor shear strength. If the insert isn't tightly fit into the opening this is the result. Especially when there isn't sufficient strength in the laminate over the insert like this one...

Imax1
QLD, 4926 posts
11 Feb 2025 8:08PM
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Zooming in as much as I can , on a computer screen , .. I can see a couple of small spots where resin came in contact with the hole. They are small.The small pieces of glass that came off the box , well. , didn't seem to stick to the box or the hole. Like a dick in a sleeve.

Imax1
QLD, 4926 posts
11 Feb 2025 8:12PM
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Select to expand quote
jdfoils said..
The foaming epoxy has very poor shear strength. If the insert isn't tightly fit into the opening this is the result. Especially when there isn't sufficient strength in the laminate over the insert like this one...


Yeah , and it at least has touch the sides to work.

Manilo
WA, 59 posts
22 Feb 2025 4:38AM
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well, job done.
tested it last weekend... so far so good
well, not really tested it since I haven't catapulted yet hahaha

now, the boom....
after checking the rig, i saw water droping from the head of the boom.... ****
took the plastic head and saw it was also cracked !! must have been on the same event

I made a 2 day repair with no success
First pump it cracked again

This pic is now, I cut all the way, to stick a carbon tube inside and reinforce it
I'm wondering the carbon laminate on the top, if it should be unidirectional fiber, like a mast - right?

Now I'm after a skinny broken carbon boom to get a piece of it and use as the tube




Imax1
QLD, 4926 posts
22 Feb 2025 9:50AM
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I wouldn't try to fix that unless you really know what you are doing.

Mark _australia
WA, 23464 posts
22 Feb 2025 12:39PM
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Agreed
because it gets fatter suddenly, you can't make the external repair wide enough. so the only way is to make a very wide internal sleeve
making a big u shaped carbon or fibreglass tube isn't easy.

Mark _australia
WA, 23464 posts
22 Feb 2025 12:40PM
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How did u repair the board?

Manilo
WA, 59 posts
23 Feb 2025 12:06AM
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Select to expand quote
Mark _australia said..
Agreed
because it gets fatter suddenly, you can't make the external repair wide enough. so the only way is to make a very wide internal sleeve
making a big u shaped carbon or fibreglass tube isn't easy.


I'll give it a try.
Too expensive boom to throw it away and buy new one
I'll try to get a carbon fiber skinny boom tube.

Manilo
WA, 59 posts
23 Feb 2025 12:12AM
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Select to expand quote
Mark _australia said..
How did u repair the board?


1. Glued with epoxi the cracked divinicell foam
2. Cleaned the mastbox
3. Insert with fiberglass and carbon the mastbox (and epoxi)
4. Sanded al around
5. Laminate 2 carbon fiber 200g cloth
6. Put weight to press the laminate (couldn't make a vacuum)
7. Painted (in a hurry cause I had races)

Some pics















barthbb
92 posts
23 Feb 2025 12:20AM
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Looks nice!!!

Awalkspoiled
WA, 531 posts
23 Feb 2025 1:28AM
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Select to expand quote
Manilo said..

Mark _australia said..
Agreed
because it gets fatter suddenly, you can't make the external repair wide enough. so the only way is to make a very wide internal sleeve
making a big u shaped carbon or fibreglass tube isn't easy.



I'll give it a try.
Too expensive boom to throw it away and buy new one
I'll try to get a carbon fiber skinny boom tube.


If you don't find a good carbon tube, then a wooden dowel will work pretty well on the boom too, whittled and sanded to be a near jam-fit and installed with a gap-filling epoxy like JB-Weld. The key will be to seal up the end-grain so it doesn't absorb water, which you can do with 2-3 coats of Marine Varnish

Imax1
QLD, 4926 posts
23 Feb 2025 8:48AM
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Select to expand quote
Awalkspoiled said..



Manilo said..




Mark _australia said..
Agreed
because it gets fatter suddenly, you can't make the external repair wide enough. so the only way is to make a very wide internal sleeve
making a big u shaped carbon or fibreglass tube isn't easy.






I'll give it a try.
Too expensive boom to throw it away and buy new one
I'll try to get a carbon fiber skinny boom tube.





If you don't find a good carbon tube, then a wooden dowel will work pretty well on the boom too, whittled and sanded to be a near jam-fit and installed with a gap-filling epoxy like JB-Weld. The key will be to seal up the end-grain so it doesn't absorb water, which you can do with 2-3 coats of Marine Varnish




Ooooooh ! As long as you don't sail further than you can swim. If it was a break anywhere else , possibly , because it's a shear strength kind of fix. This break is munted. The fibres are trashed and there is a new cut. The forces on this repair will be trying to pull it apart with strong levering wiggling action . Only an extremely well done fix including removing the bad twisted broken fibres will work. There is probably a thin plastic coating on the inside that would have to be removed for any glue to stick. The break is near the fatter part of the boom. How do you get anything to be a tight fit in there , unless you remove that entire area. Not a novice fix. Get it properly fixed or , for the love of God, buy a new boom.

KDog
364 posts
23 Feb 2025 8:53AM
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For the boom fix find a shop in your area that sells carbon SUP paddles they might have some scraps of carbon tube that they cut off when they size a paddle for a customer might be worth having a look!

jdfoils
433 posts
23 Feb 2025 9:19AM
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Select to expand quote
Awalkspoiled said..

Manilo said..


Mark _australia said..
Agreed
because it gets fatter suddenly, you can't make the external repair wide enough. so the only way is to make a very wide internal sleeve
making a big u shaped carbon or fibreglass tube isn't easy.




I'll give it a try.
Too expensive boom to throw it away and buy new one
I'll try to get a carbon fiber skinny boom tube.



If you don't find a good carbon tube, then a wooden dowel will work pretty well on the boom too, whittled and sanded to be a near jam-fit and installed with a gap-filling epoxy like JB-Weld. The key will be to seal up the end-grain so it doesn't absorb water, which you can do with 2-3 coats of Marine Varnish


Um, no.

Don't do the dowel thing unless you want to go swimming with broken gear.

Subsonic
WA, 3354 posts
23 Feb 2025 10:01AM
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Select to expand quote
Manilo said..

Mark _australia said..
How did u repair the board?



1. Glued with epoxi the cracked divinicell foam
2. Cleaned the mastbox
3. Insert with fiberglass and carbon the mastbox (and epoxi)
4. Sanded al around
5. Laminate 2 carbon fiber 200g cloth
6. Put weight to press the laminate (couldn't make a vacuum)
7. Painted (in a hurry cause I had races)

Some pics
















Nice work on the repair. Did you change the auto vent out for a normal one?

Now that the board has ingested some water, i'd be concerned about the salt migrating onto the internal side of the goretex and stopping the vent working. I've see a number of boards de laminate because the auto vent wasn't letting air out.



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"Repair experts advice - ripped off mastbox (catapult)" started by Manilo