portable tankless water heaters

[930chef]

Hi, my wife and I just purchased a Cal 34 in excellent condition. Everything has been done except there is no pressure water supply, only the stock manual pump.
I am going to pressurize the system, and was going to install a 6 gallon water heater to run off the engine. The engine is a relatively new Yanmar 3 cylinder with fresh water cooling.
Space is kind of a problem and I was thinking of other options. This is primarily for my wife to have a warm shower.
I came across a propane operated(which is already safely installed on the boat) portable tankless water heater shower made by Eccotemp for camping, off the grid type work. It puts out approx. 1 ga. per min of hot water.
It sounds like a viable solution to happy wife,happy life. It would be primarily a cockpit shower but could easily reach the shower area on the boat.
I really dont want to fool around with the engine cooling system, and the average 6 gallon w/h is just one more system to maintain, and also has the potential to fail and overheat the engine.

Has anyone used a similiar system or can I get some feedback from the sailors who have more experience than me.

We live in SoCal and we are using the boat to visit the islands and marinas up and down the coast...nothing serious.

Thanks in advance for your help...It's our first boat,and I want it to be perfect.

Kevin&Bonnie