I suppose a good portion of my boat came from Home Depot - but - the marine environment
is different from a house on land. We have vibration and flexing considerations that make some "home" supplies inappropriate for marine
eats through things that would last a lifetime in a land home.
- - Then there is the problem of failures. A burst pipe on land might be a inconvenience or expensive but on a boat in the ocean it may be a major catastrophe.
- - So for plumbing
systems on a boat it would be prudent to stay with recognized marine parts
and fittings as much as possible.
- - The major consideration with "tankless" water heaters or "instantaneous" water heaters is the open propane
flame inside the unit in an enclosed boat cabin
. The unit needs to be vented to outside which is not very conducive to ocean passages where the ocean washes over the decks. More than a few cruisers have been killed or severely incapacitated by CO build up from propane instantaneous water heaters. So the installations have to be very carefully done and the unit maintained continuously and monitored for CO leakage. All of which adds up to more trouble than they are worth.