Boat fresh water plumbing

[Bobg]

I spend all summer and a lot of time at the dock, I have an external water hose connection that is plumbed into my water system, Although I really liked it, I quit using it because I am afraid I may forget just that once to shut the valve and a connection could release and sink the boat while I am having a cold one with the neighbor. 
Question, is there any reason a boat could not be plumbed with Pex type hose and fittings? I realize it may be stiffer to work with, but any other reasons to think about? like rough seas and lack of flexability? expense? non compatable fittings? just stupid to do?  Appreciate your thoughts.  Thanks

[mregan]

I believe new boat are plumbed with Pex.  The working pressure on Pex is around 200 psi.  I wouldn't see any problem using it besides the stiffness.  It does have flexibility but definitely a 2 person job to snake it through the boat.  Check on which brand you plan on using though.  Some manu. use brass fittings.  Viega I believe uses bronze fittings with s.s crimp rings.  I think they just came out with pex fittings on their domestic water piping.  Still has the crimp rings.  You would need to buy a crimp tool for it though.  Uponor uses pex fitting with pex rings but you also need to buy an expansion tool to open the ends of the pipe to install the fittings.  I'd be leery of the pex brand at HD or Lowes.  The pex is probably fine but just check the quality of the fittings and crimp rings.  I think they are brass.
The other option on fittings are to use the shark type fittings although they are very expensive.
Another thing to think about if you use a pex manu. fittings is getting the fitting tool into some of the tight spaces to make your connections.

[waterdog]

Bob I have used PEX on my boat to plumb a shower in the cockpit.    I have had no issues with it.

You mention using PEX in the same context as a hookup to an external hose.   Were you thinking that upgrading the plumbing would allow you to use the external hose again?   I wouldn't go there.   If the PEX pipe leaks in your house you replace some flooring.  If it leaks in your boat, you might have to replace your boat.   

[Craig Illman]

I re-plumbed my boat's fresh water system with PEX and used SeaTech fittings from Sure Marine.
http://www.suremarineservice.com/sea-tech.aspx

Yes, one needs to be careful about radius bends. I did all "home runs" and put in some valves and drains to empty the rear water tank in the winter and empty the stern step shower lines.

Craig

[Bobg]

thank you everyone for your input, i really  appreciate it, and waterdog I take your advice very seriously, have been following your posts.  your mexico trip and all that you have done.  Thank you Craig for the website on the sea tech fittings.  will take your advice on that too.  The shore connection is just so darn convienient when you live on your boat that it is hard to give up thinking about it.

[mregan]

Bob
What you need is an automatic shutoff on the dock water.  There are some expensive ones online you can purchase.  A cheaper option, and a bit Rube Goldberg, would be to use an underground sprinkler valve and controller.  When you are on the boat you turn the sprinkler controller on which opens the valve.  When you are away you turn it off and it closes the valve.  Only problem is you need to remember to turn it off when you go.  Either that or you set up the timer so the valve is only open for a certain period of time then shuts when the time is up.

[Craig Illman]

Bob - I forgot to mention that Whale makes similar PEX fittings too. Neither are cheap, but they come apart relatively easy.
Craig