I'll ask the really dumb one first:

At the very bottom of my transom, there lived a cup-shaped plastic doohicky.
Having just bought the boat (first boat), I glanced at it and assumed that
it was a part of the 'pickup' for the non-working speedometer that graces my
dashboard. The boat is sitting upside down on stands on my front lawn for a
repair, and I saw this doohickey up close for the first time. The speedo
cable is cut off at the back of the speedo, so I figured if this doohickey
is a pickup/sensor, I might as well remove it and patch up the holes since
I'm doing fibreglass work anyway. Well, I removed it and found that it
wasn't what I thought it was....
It's a plastic, cup (dome) shaped thing, with a small (5/16" maybe) post
sticking out of it. I removed the 2 screws holding it on, and lo and behold,
there's no speedo cable or anything coming out of it. The guts of it include
nothing but the post, and a spring to allow the post to be pushed in towards
the transom, and then to force it back away from the transom.
So, being a boating-idiot, I'm asking the group....what the heck is this
thing? It's likely just a clip/holder for some sort of accessory a previous
owner had...trolling motor something-or-other maybe..?
My neighbour and I had a great hoot imagining being boarded by the
authorities, "Good God, don't tell me you're operating this craft without
the little spring loaded doohickey? Have you gone mad??"
Perhaps it's a hi-tech spring loaded holder for holding your swimming trunks
while skinny-dipping.....but I'm putting my money on it having something to
do with the trolling motor...transducer mount...?

Okay, next dumb question...

Old boat, 14' speedboat....Just got it, and happy with it. Now I have
something to fix. There is a center keel and then one keel on each side of
that. The 2 outside keels sit lower at the stern than the center keel.
Where the 2 outside keels sit on the last row of rollers on the trailer,
they've broken. I imagine that all the weight of the boat, fuel tank, and
motor right over the last row of rollers and while bouncing down the road,
the keels have cracked. I could see that the lines of the boat bottom just
didn't look right when it was sitting on the trailer. There were no water
leaks into the boat, and since it's a new boat to me, I didn't notice this
damage right away.
Now the boat is upside down on stands on my lawn. Looks like the keels have
been repaired already (at least twice). And whoever did it, did a crappy
job. The last person just slopped resin on the keels until it was about 1/2"
thick, and painted over it...didn't even sand.
Okay, so I started grinding away the mickey-mouse repairs, and get to the
wood inside the keel. Wet, rotten and broken where the roller sits. I
ground the high spot off the keels toward the bow and stern until I am into
dry strong wood. Removed all the rotten wood. So, now I have a foot long
section of both outer keels to replace. NOW....the sections I have to
replace are a foot or so long, and the rollers are going to sit dead center
of my repair.
DO I:
a. Replace the rotten wood with good strong wood (a hockey stick handle is
the perfect size, and would be tougher than whale snot) and build the keel
into its original shape?
b. Replace the rotten wood with nothing and build the keels up with
firbeglass cloth and resin?
c. Replace the rotten wood with a foot long chunk of steel rod (3/8") and
build the keel up around it?

There's a LOT of weight sitting on those back rollers, what with the boat
hanging out a couple feet behind them, and the motor hanging out past
that....so I would think that the foot-long steel rod inside the keel would
be the deal. If the keel's allowed to flex at all while it's sitting on the
rollers, it's going to crack again...isn't it?
I thought about using wood, but that's what was there in the first place,
and it failed. Since I have it upside down on the lawn, I might as well
over-build, right? As of now there is no cracking anywhere except on the
bottom of the keels. The boat bottom is free of any cracking. The 2 chunks
of steel rod won't weigh more than a couple pounds.
I put a small jack under the upside down boat, and have to apply pressure to
the keel from underneath in order to have the keel in the place it should
be. I'm planning on keeping the pressure on it and keep checking it with a
straight edge while I do the repair.

Assuming that I do a good job with the fibreglass as I build the keel back
into shape, what's the best way to go here?

Thanks!!