Mast tube repair

Thread starter #1
The mast tube/hole on my sunfish is leaking. i pored resin and fiberglass scraps in the bottom just slightly over the ridge previously. it looks like there is some loose pieces of fiberglass on the inside of the boat.
Should I wrap the outside of the tube and reinforce the lower half of the tube to the boat?
Is this (pic of the red boat) the proper place to cut a port?
 

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Webfoot1

Active Member
#2
Failure usually happens when the mast tube breaks loose from the bottom of the boat.
Seems like they always did a quick and ugly job. You'll have to do a lot of grinding with
a dremel tool to get the area cleaned up before you can lay down new fiberglass. Careful
not to detach the mast tube as it's not easy to get the mast perfectly vertical once
the tube is loose. If you think it's attached solidly and you're not into sailing in
high winds you could just leave as is and wrap the mast tube in a couple layers
of fiberglass. The down side is once the mast breaks loose sailing it cracks the
deck and makes a big mess. Short of popping the deck that's where you'd put
the inspection port. I'd make sure to put a reinforcement ring under it as the
port will be taking some stress from the deck. The stress aspect almost makes
me think popping the deck would be better. Usually when you see a repair where
the mast has broken loose they end up re fiber glassing the entire area around
the mast hole. More that one way to skin a cat so do the repair according to
you comfort level. Oh, a leak could indicate mast has started to pull away from
the hull or the job was flawed from the factory. Viva La Sunfish, a model of
fine craftsmanship it never was.
 
Thread starter #3
I have separated the bow just enough for the backerblock but I really don't want to do that again.
I could not find reinforcement rings listed. Do you make them? Maybe out of a plastic kitchen cutting board?
For the strips of glass attaching the tube to the hull, do I grind off half of them and put new ones down that way it's still keeps position but might bond better? Or scuff and glass over everything?
 

L&VW

Well-Known Member
#4
This older thread might be helpful:
Mast Step Fix
:cool:

Interesting that a similar photo—with a red deck and green masking tape—appears at the above, older, thread.

Is this the same Sunfish, visited after a few years?
 
Thread starter #5
I did read that thread and stole the pic. They said it was a Canadian Sunfish. The insides look way different than mine.
 

Webfoot1

Active Member
#7
The reinforcement ring could be made out of plywood, split at a angle and
corkscrewed into the inspection port hole. Trying to work through a hole
is difficult. I'm wondering if it would be easier to use 2-part epoxy putty
around the base of the mast tube. If you scuff and glass you are assuming
what was laid down at the factory is still secure. Seeing as there is no was
to test it I guess it just comes down to whether it's worth the trouble or not.
 

L&VW

Well-Known Member
#8
Now that you've separated the deck, what is the dark material that surrounds the mast tube at the arrow?
Fullscreen capture 6152018 72553 PM.bmp.jpg

I only ask, as it's easier to work on the deck and hull, should the mast tube be totally removed from the boat. (For inspection and repair).

Alternately, the tube can be cut off, the hull cut out, repair to base more readily made, and reinstalled with a fiberglass sleeve (external to the existing mast tube at the deck). The weight penalty would be minimal, the hull would be more resistant to flexing, and the mast tube twice as strong as factory.

Just a thought. ;)

.
 

beldar boathead

Well-Known Member
#9
Now that you've separated the deck, what is the dark material that surrounds the mast tube at the arrow?
View attachment 26462

I only ask, as it's easier to work on the deck and hull, should the mast tube be totally removed from the boat. (For inspection and repair).

Alternately, the tube can be cut off, the hull cut out, repair to base more readily made, and reinstalled with a fiberglass sleeve (external to the existing mast tube at the deck). The weight penalty would be minimal, the hull would be more resistant to flexing, and the mast tube twice as strong as factory.

Just a thought. ;)

.
L and VW, this seems unnecessary and overly complicated. Have you actually done this, or is it simply speculation? BB
 

L&VW

Well-Known Member
#10
There's more than one way to do this repair. We've seen an experienced Sunfish restorer (Mixmkr) here fix everything from through the hull (underneath). Overall, his are invisible—yet lightweight—and strengthening repairs. :cool:

Mast steps haven't been a problem with my five Sunfish (formerly six), but if I wanted to keep the original straight-up mast position, this is how I'd tackle it. Especially as working through a small port makes too much of the endeavor guesswork, which may require a later "redo". :(

The "Ultimate Inspection Port" allows the passage of large corded tools, but I'd still prefer taking-on this repair once I've eyeballed the problem outside the Sunfish.
 
Thread starter #11
I'm not sure what the dark ring is. I didn't install it and the boat wasn't opened up before me. Maybe reinforcement ring?
I'm thinking I'll either use a borescope or video chat myself inside the boat. I will also be able to fit a die grinder my existing 5" port behind the coaming so that will give me more room.
 
#12
Did you retest for leaks after you applied the resin? Are you sure the mast tube is loose? As others have said sunfish do not usually have issues with the mast tube. I would have leaked tested and gone sailing unless you put a big load on the mast. I would put a mast cleat on for the halyard to lower the load on the hull and deck.
 
Thread starter #13
The mast tube is not loose. Only leaks but it doesn't look very nice from inside the boat.
I filled bottom of the mast with resin/fiberglass bits and it held water over night. I used the boat 5 times and now the mast tube leaks again.
 

Webfoot1

Active Member
#14
Well, it's always good to know about impending failure even if you don't know what's
failing. Perhaps you can make a cap for the mast hole, pour in some soapy water and
pressurize the mast hole. If there is water in the mast tube I would assume water might
be coming in from a leak in the hull somewhere. These older boats tend to leak at the
hull/deck seams. Mostly where the hull flexes across from the ends of the splash guard.
 
Thread starter #15
I have leak tested the boat. The it has a couple screw hole leaks but the mast hole is the only major leak. It also no longer holds water in the tube. I could pore another 1/2 of resin/glass shreds and fix the leak but I'm not sure how far above factory I should fill the tube.

I'm also concerned about the the glass cloth that is sticking out (arrows in pic)
 

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L&VW

Well-Known Member
#16
I have leak tested the boat. The it has a couple screw hole leaks but the mast hole is the only major leak. It also no longer holds water in the tube. I could pore another 1/2 of resin/glass shreds and fix the leak but I'm not sure how far above factory I should fill the tube. I'm also concerned about the the glass cloth that is sticking out (arrows in pic)
None of the factory mast tube "wraps" is pretty. :oops:

I wouldn't exceed the factory depth at all. The leverage of a mast with a filled sail could damage the mast tube. If more than an 1\8 inch has been added with your mix, I'd sand down to near-normal depth.

Try another mix, but wrap the mast with something like a thin layer of Styrofoam coffee cup and masking tape. (Something that rapidly deteriorates). Displace your mix to fill the tube better and higher, (with the wrapped mast or a substitute) but assure the mast can be removed afterwards! :confused:
 
#17
I would try to pinpoint the leak a bit more. If you fill the mast tube half way does it drain right into the hull? Or does it hold water? Maybe it only leaks when you fill it all the way? Since you've already got good access to the interior I'd AVOID adding any more resin/mix to the mast hole unless you can see chips/cracks in the wall of the tube. Use fiberglass tape (it's not tape, but it comes in strips that have finished ends so it's easier to work with) and wrap the tube from inside the hull. Cover your deck so you don't drip resin on it. Just painting thickened epoxy around the mast step from inside the hull is probably enough, may not need the tape, but I guess it would be added insurance.
 
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