Sorry For Taking So Long
SeaRanch to get back with you. The boat came with it, it is under the sink like yours. The early 387's had a 20 gallon hot water tank, and it wasn't until after mine that enough feed back came in to let the folks down in Largo know that there were problems getting that tank to heat up to a temperature that was satisfactory, especailly up in the colder temp waters like I have. At least, that is what Warren, the plant manager down there told me. So they cut back to, I think, an 11 gallon tank. He offered to exchange mine for the smaller tank, but I really didn't want to give up the 20 gallon size. I supplement my heat exchanger in the winter time with the use of the electric heating element when I am out on the hook in colder weather during late fall and thru the winter into the spring time. Once the water temps get up like I said, then I rely strickly on the heat exchanger to replinish the hot water.
Let me know if you want some pics, you may be able to get one of the larger tanks from Warren if he has any extra ones or exchanges.