hoses

Just got back from dewinterizing the boat. I found that my 1-1/2 galley drain line was split open where it connects to the through hull. Could have been a big leaker. I went to West Marine to buy a new hose and was surprised to read on the label that Shields Mtiflex is not recommend for below...

I have the 1997 Hunter P 42. The engine hoses to the hot water heater are leaking lots of coolant through numerous pin hole leaks. My service yard is unable to access the hoses for replacement. Has any P 42 owner had to do this? How? Any advice would be greatly appreciated.