Tag Archives: colloidal silica

Bruised boat, bruised ego

starboard_hull_damageLast summer I was merrily heading into Toronto’s inner harbour through the Eastern Gap*. I was busy lounging behind the wheel and talking with friends when one casually said “we are headed straight for a big green thing”.  That big green thing being the big steel buoy making the inner entrance to the Eastern Gap. I turned the boat to port and the wake pushed the buoy away from the a boat,  only to have the buoy swing back back with a vengeance and smack the hull just below the rub rail on starboard. Ouch.
The impact shattered the gel-coat and the underlying layers of fibreglass. It didn’t look too bad and I left it for the season as it is well above the waterline close to the forward sling marks.

What king of sailor sails straight into a big green buoy that he knows is there… ugh.

Repair #1
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Finished repair.

Peeling back the layers of crushed gel-coat and fiberglass mat, I discovered the damage was much more extensive than it appeared. There was considerable de-lamination between the many layers however the lowest layers were just bruised, not cracked. The damage also extended in a much larger radius then the gel-coat damage itself, presumably from the fibreglass flexing in.
I couldn’t access the damage from the interior unless I did a massive cabin disassembly, so rather than cut a hole , I decided to grind down and re-glass from the outside, leaving the bottom most layer intact.

After applying a few layers of mat and resin I levelled the patch with a sander and enlarged the grind. You can see the wound get bigger in the photos. Complicating the repair job was an unusually cold spring. I used a heat gun to warm the hull first and then gently warm the repair at several intervals to ensure the resin kicked.

Continue reading Bruised boat, bruised ego

syringe and a spade

Once I had possession of the boat, I gave the rudder and prop a close inspection. The rudder seemed to have a lot of side to side slop/play, at the bottom tip it seemed to be about an inch (if memory serves me correct). As the boat was on the hard and I didn’t do a sea trial I figured that this play would be, at the very least a clonking noise on the hook. Seeing as I was in for a pound with the hull I figured I’d tackle this  job.

DSC00069

I looked into replacing the big white lower busing, but it isn’t available from Hunter, but I did stumble upon a solution used by others as outlined in the West System Epoxy manual. It involves drilling holes in the bushing and injecting epoxy with colloidal silica (for bulk/viscosity) and graphite powder (for lubrication). It seemed a reasonable method so I forged ahead.

Dropping the rudder required digging a hole in the yard, there seemed to be several holes that spring! There is definitely a benefit to being on gravel instead of pavement! Funny thing is the hole filled up with water in heavy rains and I ended bailing the hole out to reinstall the rudder.

DSC00071The technique calls for waxing the steel bushing, drill holes, reinstall the rudder and then inject epoxy with 50/50 mixture of silica and graphite. In my case I drilled three holes on each side and three on the front. As you can see from the photo the epoxy merged into one big pad. I like this technique as it creates a zero tolerance fitting that would be difficult to achieve otherwise and I suspect is better then when it left the factory.

It stood a season and seems fine – there is a posting out there with