gooseneck
Found it!
When I bought the boat in late fall, I put 30+ years of 'stuff' in two piles.
One pile was GARBAGE.
The second pile, anything I thought might be useful/handy, or anything I couldn't immediately know what it was. The gooseneck fell into the second category.
One less thing to buy!
or, said another way,
Now I have money to buy something else for the boat!