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Cracked mast step/tube.

23hallt

New Member
so in early august I bought a 75 sunfish from a guy down in CT, he didn't mention that the coaming was falling off, or that there was a crack in the mast step. What he did tell me was that it had been used at sailing schools since the spring of 2017 and that some knucklehead had crashed her into a dock and she had been hastily repaired and put
back to work. I know it needs to be fixed but how should i go about making the repairs?






.IMG_3046.JPGIMG_3043.JPGIMG_3041.JPG
 

L&VW

Well-Known Member
The repair looks strong. :cool:

I'd use paint remover to get to raw fiberglass. With 24-grit (if you have any), sand over the patch by hand (and wood block), fill the voids with MarineTex, smooth (using wax paper), fair to match the hull's side.

The mast step could use a post-card sized patch. Tape wax paper to the mast, wet up a glass-cloth patch, and press it against the defect. (Wedge the mast firmly). Allow to set, add water, check for unseen leaks.
 

23hallt

New Member
Hull doesn't leak she sits high in the water and sails well. I took her out on the water a few times prior to me noticing the crack and she sailed fine! I will do a leak test tomorrow, and should I do that on the inside of the mast or on the outside?
 

beldar boathead

Well-Known Member
To check the mast step, fill it to the top with water, wait a few hours, and see if the water level has dropped. If it is sound and the boat stays empty when you sail it, you can then just do cosmetic work if you want.
 

4cpus4me

Member
I looked at the bow repairs and then I'm squinting while looking at that mast step photo thinking, "Go sailing!"
 

L&VW

Well-Known Member
I will do a leak test tomorrow, and should I do that on the inside of the mast or on the outside?
Remove the mast and fill the mast step to the brim. Wait a few hours. From your excellent photograph, I'd expect a very slow leak--or it might not leak at all.

For the coaming repair, use the search feature (upper right hand corner) and search "splash". One way (easiest) to repair is here:

 

23hallt

New Member
So, I completed the mast tube test, and it's leaking. using simple physics, knowing that where it was water tight should dry out, and where it is leaking it should still be damp, I was able to track down where the leaks are. so I have a compact phone, so I stuck my phone thorough the forward inspection port, I set a timer for 3 seconds, and set it to flash to better see moisture. where ever you see it sparkling, is where it's leaking. using that information, there is a crack running along the top, where there is a seem, where some glass has peeled away I'm guessing there may be some hairline cracks then the more obvious one, the main crack itself, i'm unsure where to go from here. The last image is the before image of the external of mast tube.
 

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Wavedancer

Upside down?
Staff member
If the only crack is near the top of the mast tube, the water level in the tube test should have stabilized just below that area. True?

I have 'repaired' such a crack by smearing MarineTex on the suspect area. It's held up just fine. Alternatively, one can fix this internally by wrapping wetted glass fiber cloth around the tube. But that requires access and more skill (and materials) than I have.
 

23hallt

New Member
There is also a bigger crack about 8 inches long that runs from below that crack along the top that runs towards the base
 

L&VW

Well-Known Member
Wavedancer is correct. Scuff with sandpaper,wipe with acetone and epoxy. Let dry and go sailing.
Here's more :) including the use of a balloon:

 

L&VW

Well-Known Member
Refill with water, record minutes to drain to previously-determined leak level.

From the outside pic, I see a rough dark letter "J" fracture. From the inside pic, I see a rough dark letter "J" fracture--but backwards.

I'd sand, wet with resin, and put a "wet" postcard-sized patch on the outside and go sailing.

Re-test time to drain water to same level to determine effectiveness of repair. :)
 

23hallt

New Member
Ok, what is a good in section port? the current forward inspection port is too far aft to react the mast tube.
 

L&VW

Well-Known Member
Ok, what is a good inspection port? the current forward inspection port is too far aft to reach the mast tube.
To avoid adding another port, do the same repair--but from the inside. I haven't done this repair myself, so see the above "balloon procedure". A lighter cloth (4-oz) would be a better choice to avoid "crowding" the mast space.

Sand or debris? I suspect the mast wasn't fully inserted (to cause that kind of mid-fracture).
 

L&VW

Well-Known Member
Ok, what is a good inspection port? the current forward inspection port is too far aft to reach the mast tube.
You'll probably need to spend more than $15 for a quality inspection port nowadays. Holt, Becksons, and Py-Hi are good manufacturers, and may still be USA/UK-based.

I bought a "cheap" $12 port from China, which doesn't come close to sealing. :(

Even worse, should I step on it, I'd expect it to fold and drop into the hull! :confused:

'Course, any access for the repair can be sealed-up (stronger) with glass and epoxy without spending money for an inspection port. :cool:
 
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