Replace the cockpit sole bearing
(or, when good ideas go bad...)
February 2005 (revised March 2005) --
When I pulled the bearing, the bolts were bent because they were at an angle relative to the bottom of the sole. To avoid that, I made shims out of fiberglass scraps.
This was a great idea. But it didn't work.
More on that later.
The bearing itself is corroded, but I couldn't
do much to clean it up. The chromed bronze is fine,
and the aluminum shim is structurally sound.
I removed surface corrosion, and etched/sealed the metal. However, I'd have to sandblast it to get it
clean enough to take a finish, and that would ruin it.
So I'll live with the ugly -- Although I have a plan to hide it eventually.
I pulled out the greasy hunk of hose which was installed when recoring the cockpit sole. It did a great job of keeping epoxy away from the rudder post and the interior of the boat.
Cleaning all the grease away from the edges of the hole took
some time. I started with a rag, then used denatured Alchohol, Mineral Spirits,
and when there was little visible grease left, a final scrub
The sole is higher than it was a few months ago, because it
was jacked up level, then fiberglass was added to form it into a slight dome
to help water run off towards the drains.
I traced the outline of the bearing, and used my Handy Dremel
Tool to slowly grind down
into the new sole surface.
Then the bearing was set into place, and a good thick gasket of Lifecaulk was injected under it.
The bolts are not finished in this picture. These bolts are
just keeping the bearing aligned with the holes in the sole, and keeping
caulk from gooshing down into the engine room.
Caulking this was tricky, because one doesn't want caulk to goosh down around the rudder post.
So I just lightly set the bearing into place, and screwed the top "donut" onto it to ensure that the bottom of the nut and the top bearing surface are flush against each other. After the caulk cures, I'll go back and put longer bolts in, and crank down on the thick caulk gasket.
It was ground down to the top of the Knytex tape,
(which was laid over the top of the old sole,)
then cleaned up well.
To drill the holes straight without hitting the rudder post, I had to use a 12" long drill bit.
There was an existing aluminum backing plate,
which I never removed.
It surrounds the rudder stock.
I missed the old holes, somehow, so just drilled new ones, then used my Handy Dremel Tool to enlarge the 1/4" holes enough so the bolts could pass through at an angle.
Originally, this plate was bolted to the underside
of the deck at all four corners.
However, all that really did was put four leaks into the cockpit sole. All of the pressure on this bearing is vertical, and down.
The only time the bearing will get pushed UP is if the rudder bangs down on something.
I hope that never happens, but in case it does the backing plate will still work. The four bolts around the bearing will hold it in place.
I made a new bearing surface from 1/4"
Delfin AF. You can see here that it's significantly larger than the old Oil Impregnated Nylon.
I'm going to remake it out of 1/8" thick Delrin, because I want that extra play in the donut to move the rudder up and down.
Right now, the top of the post is flush with the top of the Donut, and if the donut is tightened up there's another 1/8" or so. I'd like the threaded portion of the post to extend up about 1/4" past the donut.
A good slathering of grease was applied to the bearing
surface where it mates with the rudder post.
There's no lateral pressure on this bearing. It's just a thrust bearing, holding the rudder up.
After two weeks, the caulk is cured enough so that the bearing can be cranked down and the caulk gasket compressed.
Drilling the holes all the way through was a challenge due to the close proximity of the rudder stock, so I used a 12" long drill bit.
(This bit is also useful for drilling long holes vertically
into wet stringers.)
The bolts are well packed with Lifecaulk (a polysulfide.)
With the bearing bolted down, the top was packed with grease.
Those 1/4" bolts are too close to the rudder stock to allow for washers, and in fact there wasn't room for me to use nylon locking nuts on two of the bolts. The fiberglass shims will have to serve. There is a dab of blue Loctite on the non-locking nuts., and the rear bolts just barely kiss the nylon in the lock nuts.
Here's the pic with the shims in place.
Well, it was a good idea, but it interfered with the steering.
More on that later.
The flat head bolts sit slightly under the surface of the
bearing, so the Delrin AF can slide around over them
without a problem.
Finally, the big round nut
was tightened up with a strap wrench, and the little hex head set screws
were set in place.
I really need to polish this up a bit and take another picture from the side, but was in a big rush because the main project for the weekend is the new fuel tank.
Before putting the non skid on the new cockpit sole surface, I'm going to make a "vanity ring" that goes around this bearing, just to seal more caulk in place.
But it's fine for now, as I can put the new fuel tank
in and start on the steering.
Once that stuff goes in I'll never be able to reach the underside of this bearing again.
So, naturally, I dropped one of the shims under the new fuel tank.
This required pulling the new tank back up and retrieving the block, so that it doesn't work its way down to the limber holes and create a little dam.
Fortunately, this was the third item I'd dropped down here (the first being the key for the steering quadrant) and I'd already drained the tank and lifted it up twice. Arrh.
Then I slipped the new Delrin AF bearing plate on top.
I made a new one out of 1/8" thick Delrin AF, because the 1/4" bearing was too thick.
Update March 2006 --
Well, here's why it didn't work.
The top of the radial steering wheel
hits these nuts, and I couldn't
make the steering fit.
Even after cutting the bolts off
flush with the nuts, it was too close
for comfort and the aft nuts
(on the left hand side of this picture)
scraped the top of the radial wheel.
This little flexible grabber tool is essential boating gear.
As part of the whole cockpit
I added this inspection port under the helm seat
for easier access to the steering.
It'll actually have a Bomar deck plate bolted down, but for now it's just a big hole.
It made replacing the bolts really easy,
and I'm already glad I did it.
So it's back to the way it was originally
Now I know why they did it this way.
I used extra long bolts, since they'll be
cut off flush, and clamped vice grips on the bottom to hold the nuts solid
torqued down hard on the bolts.
I tightened the bolts enough so that they bent a little bit trying to make the nut
flush with the backing plate.
Note the piece of string
(or dental floss, in this case) tied onto the vice grips. It took years to figure out that trick, so that when I drop them I can get them back quickly without having to lose 1/2 hour digging around in the bottom of the boat.
After cutting the bolts flush with my Handy Dremel Tool,
I stuck a dab of Red
Locktite on the ends.
I don't think those nuts will vibrate off.
That backing plate is ugly, but there was no way to remove
it and clean it up without dropping the rudder, and the boat's in the water
so that wasn't an option.
I'll never see it again, anyway.
Here's a pic of the "vanity ring"
on the top side.
It'll be covered with nonskid like the rest of the sole.
The idea is to have a nice solid ring of caulk
around the bearing, to prevent leaks. It'll also help me to avoid breaking
my toes on the bearing
when I'm sailing barefoot.
It's vinylester FRP, and details about construction
are on the cockpit sole page
(revenge of the grinder) although as of March 2006
that particular page is still under construction.