yes, i have an actual boating question

I replaced all the 3" exhaust line on the engine (10', a bargain at
$2/ft!).

NOW i need to replace all the cooling lines leading from the seacock
to the engine, and the engine heater hose. the engine has a heat
exchanger and is cooled with an anti-freeze/water mixture.

so why type of hose should I use? is there a marine grade or can i use
the regular heater hose used in cars? rubber is pretty impervious to
salt water....

hope it's cheaper than the damn exhaust line!

thanks all