Mast Step Fix

FishingAgain

Ready to come-about
Though there are already many posts recommending doing the 'full' fix of leaky mast steps from inside the hull, and posts describing the process, I figured it might be useful to share my own success story with a few pictures. I fixed it inside the hull AND poured a new base in the 'tube'.

I bought my my 1972 Grew Sunfish (made in Canada) last summer and like most, it was waterlogged and needed TLC. I did the usual leak test, fixed a couple deck-hull seam cracks but knew I had to tackle the mast step, which had bubbled like gangbusters during the leak test. Water also drained quickly from it leaving 1" in the bottom. I decided to fix it from inside the hull, partly inspired by first-hand accounts/cautionary tales on this forum and partly from seeing a good size crack when pictures of the bottom of the step were magnified (attached). I'm guessing the boat was stored deck-up with water in the step over several winters, causing a large crack to form.

I acquired the necessary equipment including West System Resin and Hardener (I used the Slow), fibreglass cloth, tongue depressors, mixing buckets, disposable paint brushes and all the necessary protective/safety equipment. First step was to cut (another) deck access port, this time 6" (pic attached) using a Dremel tool with cutting attachment and 'router' guide - this has worked well for me on my other two ports. I covered the cut edge of the deck with duct tape and then added more tape when I cut my self 2-3 times. Vapour barrier worked well to protect the deck around the access hole.

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I then started to remove LOTS of spray foam - my Sunfish had incredible amounts in it (before and after pics attached showing pre--repair view of the mast step from the port behind combing). I left only enough spray foam to keep the foam flotation blocks firmly in place. The weight of the removed foam in the garbage bag demonstrated what I had known - that it was holding close to 30 or more lbs of water.

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Mixing West System is easy with the metered pumps. Follow the directions (how novel) and you'll be fine. The learning curve for me was how much epoxy to apply before placing the cloth strips. The first 3-4 were frustrating (especially at the farthest side of the tube) but I got the hang of it and felt like a pro within 30 minutes. I learned to be liberal with the epoxy. The "before" and "after" pictures of the mast step inside the hull are attached. I put 5-6 layers all the way up the 'tube' and approximately 8-10 layers at the base.

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I then poured a new base inside the tube. I debated this for a long time but decided to fill the crack from inside as well to prevent any water at all from sitting in the crack and freezing during our nasty Canadian winters. I'd rather lose 1" of mast step than have to repeat the repair. I used an old plastic juice bottle to create a funnel and it poured perfectly with no splashing. I filled the old divot at the bottom and around 1" up, covering the crack. Once cured, I dropped in a teflon disc for the mast to spin on. I figured it wouldn't hurt.

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Two days after the job, i was out sailing and that evening I filled the step with water an it stayed there for 15 mins until I got bored and removed it. It feels good to have the job done and know I've, at minimum, greatly decreased the chance of a structural failure in the future.

Thanks to all members who contributed to prior threads on this topic - I would have been lots without your providing your insight.
 

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The Teflon disc is a nice touch. :cool: Nice repair. :) Did you mix-in glass fibers (or beads) with that last 1-inch pour? I only ask, as resin by itself doesn't have a lot of strength—although it will successfully seal a thin or tiny leak.

My preference is to use slow hardener. You can work less rushed, and come back the next morning to determine what else needs fixing. The last time I had professional help using the fast catalyst (on a warm day), the epoxy melted the container it was "cooking" in, and "steamed" for half an hour! :oops:
 
I decided not to use fibers or beads - as you said, I just wanted to ensure the crack was sealed. As for the hardener, yup I chose to err on the side of needing lots of time to work and it paid off. It also ended up being a VERY hot day, so I was extra happy I went with the slow.
 
great pictures, and holy smokes - there was a TON of extra foam fill in there!
Indeed... when I compared to other pictures on this site I couldn't believe the excess foam and of course it was all saturated with water!
 
A Canadian Sunfish, eh?
Yep, apparently. My father had a Grew Sunfish as well. No serial# plate anywhere I dated it based on the presence of the cockpit aft cubby and having a stripe on the blow only. I'm not sure when Grew stopped building Sunfish but they made powerboats up until they shuttered in 2010/2011. http://grew.ca

I took this picture the day I acquired the boat (thus the condition!).

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