Box came from UPS. We have parts.
Time to get to work.

Step 1 was to drain the block as best as possible. This is a tedious exercise because the coolant just trickles out.
We can easily drain about 3 or 4 gallons out of the six gallons that are in there.
I guess the rest will simply stay in there, along with the new antifreeze we bought at AutoZone.
Step 2 was to remove the raw water hose sections. There are a few right-angle pieces: pump to oil cooler, oil cooler to main cooler, main cooler to transmission cooler.
There's a longish run from the transmission cooler to the "injection" on the exhaust line.
Step 3 was to replace the transmission cooler. The old one is relatively new and can be kept as a spare. It's not totally broken. It wasn't too difficult to remove or replace. Awkward, but not too difficult.
Step 4 was to replace the oil cooler. I've got the cooler removed.
But.
The hose from cooler to oil filter has a ⅜" street elbow that I cannot get off the oil line.
I'm going to try and get the oil line off the oil filter and take the thing to a boatyard to see if they have a vise I can use to carefully unscrew the oil line from the street elbow.
If I can't unscrew the elbow, it's probably time to replace the oil line entirely. We'll find out tomorrow.
Socialization
We spent the morning chatting with the crew of Shawnee.
We had dinner with the crew of Joie de Vivre.
So nice to bracket a messy engine job by hanging around with other cruisers.