Water Hose from Water Heater

[martinjrichter]

Slightly off subject, but the rage in homes is the "tankless" water heaters. That seems to me to be a perfect fit to any boat. I don't like the notion of a 40 hp water heater if you get my drift when a tankless system gives nearly instant hot water using gas or propane in a small package(about the size of a coffee table book).

[osirissail]

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 use. Salt air environment 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 and electrical 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.

[Ishmael]

Originally Posted by osirissail

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 use. Salt air environment 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 and electrical 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.

I agree about the tankless heaters - not a good idea on a boat (except a houseboat on an inland waterway, maybe).

PEX tubing is superior to polybutylene in every way. Because it's plastic, it's not adversely affected in a saltwater environment, and the fittings are solid brass. I'm not sure any marine-rated materials/systems can improve on those qualities. Someone above mentioned that manufacturers are using PEX with the quik-connect "Shark Bite" fittings. I wouldn't use those, I'd use the expander tool with the PEX rings that shrink back down over the barbed fittings. The tubing and fittings are rated to withstand over 200psi (of course that goes down as the temperatures increase). The only thing I'm aware of that is detrimental to PEX tubing is direct sunlight, but that shouldn't be a problem down in the bilges, behind settees etc..

[osirissail]

Brass and any metal other than bronze or stainless steel does not hold up in the marine environment for very long. Banded crimp fittings are especially problematical in the marine environment where being able to access and repair is critical. That is why the push in fittings from Whale and Sea Fit and others are the mainstay of potable water plumbing in sailing/power boats. The current pipe/tubing being used is polyethylene. Polybutyl having been discontinued by the mainstream marine industry years ago.

[Ishmael]

OK, I'll take your word for it. But for the record, I wasn't recommending the metal crimp rings, either. I think they're a lazy/lousy way to make the connections even in residential plumbing. I've also seen push fittings fail (usually after freezing in winter) far more often than the fittings I was referring to. As a rule (in residential plumbing) I don't use the push fittings anywhere where a failure can cause damage - that pretty much limits my use of them to crawlspaces (I just don't trust them). It just surprises me that that would be the new standard in the marine industry, that's all.

[osirissail]

If you get a chance visit some boat shows, the fall is the big season for them. Instead of oohing and ahing the designs and pretty girls the vendor uses to lure into their boats, open the cabinets and peak around inside - behind - and you can see what is currently being used. That is a good way to find out what the current "standard" is for any particular vessel system.
- - Also you can get some good ideas to steal and use on your own boat. I moved my portable water tank vents from outside the hull to spigots in the galley sink and head sink after seeing high end boats that were doing that.

[Ishmael]

I'm too far away from buying anything to make boat shows a worthwhile time investment at this point. Newports a fun time, but I'm just not feeling in the mood this year! I'll probably take the family to the Scottish Highland Games in New Hampshire, instead (our annual dilemma).

[osirissail]

With that I would respectfully disagree. Rooting around a boat show is a great way to keep the desire/passion to go cruising alive. Seeing how the boat vary from small trailer sailors to large opulent floating dens of pleasure and everywhere in between is very interesting. Also for me, at least, I like to mull over ideas and perceptions for awhile and then a better resolution of needs versus desires forms.
- - One little "truth" evolved over the early years of visiting boat shows manifested itself in the realization that for any size sailing monohull there is a wide gap between the prices of mainstream boats and the upscale versions. And that is the presence of built-in insect screens on the overhead hatches marks the upscale boats. In essence it is the "extra" large amount of "finishing" details that marks the upscale boats.

[GordMay]

FWIW: PEX is made from high density polyethylene (HDPE); and contains cross-linked bonds in the polymer structure, changing the thermoplastic to a thermoset.

[rossny]

Is there a difference between the 1/2" blue or red pex tubing from home stores and the 1/2" pex from seatech ? I know the fittings are different so they are worth the premium price. Is mixing manufactures efficient cost cutting or penny wise pound foolish?

[osirissail]

Without answering specifically, I have found that there are three tiers to pricing of stuff you can use on a vessel. The highest priced are marine suppliers; down a bit is the RV suppliers; and lowest the warehouse home supply and even local home related businesses.

The are quite a few things that are identical and used by all three sectors, but the prices vary from marine to RV to home sources. So researching the item and finding out if it is identical to stuff from other sources can save quite a bit of money.

[NY GIN]

I recently had a rupture in my boats copper fittings. I have gone on to inspect all the freshwater piping and noticed it to be very old copper line. I am going to be replacing it all in the next week or two and have been contemplating this very debate of purchasing the Pex system from a residential plumbing store or the marine grade system from a marine store. My boats just 38' and there really isn't all that much piping when it comes down to it so I can't imagine the savings to be that great from residential to marine. Although these days, every dollar counts. Still researching this.....

[donradcliffe]

I replumbed the house with PEX using the expander tool and can heartily recommend it. However, I couldn't get the local plumbing supply shop to sell me the materials because I was not not a 'certified' installer. Had to buy them through a plumber friend. All I could find at Home Depot was the crimped metal band fittings and the sharkbite stuff.

[osirissail]

Just a caution to use PEX fittings and connections that are not "bands" or crimped metal. The salt-air environment on a cruising boat will most likely, corrode the metal band and the joint will no longer be secure. That is one of the differences between land home applications and marine applications.

[NY GIN]

Originally Posted by osirissail

Just a caution to use PEX fittings and connections that are not "bands" or crimped metal. The salt-air environment on a cruising boat will most likely, corrode the metal band and the joint will no longer be secure. That is one of the differences between land home applications and marine applications.

Yes have read all about that. My buddy owns a plumbing business so I will go through him for all the tubing and proper fittings.