Well, it turns out when I sucked a line into my thruster, I did do some damage. The line pulled tight enough that it ripped through the plastic on the tunnel around the thruster. This appears to have torqued it against the hull.

I started noticing sea water in the aft bilge a few months ago and after pulling up the floor I’m 90% sure this is the cause (I can see seeping coming from where the thruster is attached to the hull). Trevor and Dave both suggested the rudder, since the leaking is worse under way and it’s a known failure mode, but I just don’t see it (the top of the shaft is consistently dry). The good news is I was planning a haul out anyway, for bottom cleaning and paint. Bad news is everyone is booked solid. CSR took mercy on me, since it’s a leak, but they still can’t get me in until 23-May. Sitting at the dock, I’m getting maybe two pints of water per day. Under way, I’m getting maybe two pints an hour. I’m concerned that cruising is making it worse, so we’re dock-bound until haul out.

Water comes from the transom into this compartment under the floor.
Dried out
The front of that compartment does not have a drain to the compartment with the bilge pump.
So, the water leaks in along the bonding strip.
Check out that corrosion.
There’s water under the thruster
It looks like it’s weeping in from where the tunnel is attached to the hull. But, it could be from the coupler in the thruster itself.
There’s a fair amount of corrosion on the thruster
The top of the rudder is also a place where water gets in. But this rust is from a leak in the deck plate for the emergency tiller.
Also seeing sea water in the center bilge, which isn’t connected to the lazarette bilge.
Also a tablespoon under the shaft seal
Spring day at the dock

Ok, so plan of record:

  • Haul out for bottom paint and zincs
  • Replace the stern thruster tunnel and coupler, remount to the hull
  • Put a drain hole from the center lazarette bilge to the forward lazarette bilge, which has the pump
  • Repair the bonding strip (maybe move it)

There’s a little water in the midship bilge as well as under the generator. None of these is connected, so I suspect the respective raw water intakes. I tightened all of the hose clamps. I had an old leak from the emergency rudder port which I fixed back in Feb-2021 (though I didn’t clean it up as I should have), but the top of the rudder post (another ingress point in the laz) remains dry.

A note on part sourcing and work planning:

North Pacific has been great at helping me plan out the work. Both Dave and Trevor weighed in on the troubleshooting and Imtra tech support helped me identify parts to have on hand for the haul-out, which Trevor helped me source. The documentation is very good if you know where to look and who to talk to.

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