Plumbing Refit

I have a 50 foot Krogen trawler that my wife and I are refitting/rebuilding. Looking for suggestions on plumbing. We will be using PEX. Question is, I can run one 3/4 inch hot and cold water line and a 3/4 raw water line all the way to the bow and tap off of that at each location, galley, foreward head etc. or I can run a seperate 1/2 inch hot/cold line to every use point from a manifold system. what would you do ?

Greetings,
Mr. 44. The only comment I can make is have as few connections in the most accessible locations as possible.

about to do mine also....just using 1/2 inch though as that's more pipe than the average small pump can handle...but the bigger boat could certainly benefit from 3/4.

I'm electing to NOT use a manifold...but that's my boats layout...just doesn't make sense for me but many boats it does. I have logical places to cut off with valve versus a whole manifold system so that's my choice...but I considered a manifold till I realized just not enough connections to really warrant one and where the pipe runs/pump are...just didn't make sense.

Draw it out both ways and see what makes the most sense for where your tanks, dock inlet, pump, etc are and see if trunk runs are less material or easier to run than a manifold system.

i know its the 'right' way but i hate the manifold system. I have a PEX manifold system in my house and i hate it. More lines+manifold = more places to leak. Also, when you want hot water, in the sink, then in the shower, then in hte other sink bowl, each time you have to wait for hot water.

my advice is run 3/4 trunk lines for hot and cold, then T-off for the fixtures.

Maybe someone else can make a better argument the other way...

Well, that would certainly be easiest. Way less connections. Valves at each use point. 3/4 to the bow for anchor washdown. Check valves at the tank and dockwater hookup. We will use a 12 volt Delavan "fatboy" pump for fresh water and another for raw water wash down. These pumps are great, much better than any "marine" pump.

A good argument can be made for manifolding but I'd run 3/4" lines and tee branch them. PEX fittings are pretty darn reliable. Proper support and care around bulkhead penetrations would be cause for more concern than fitting longevity IMO.

I dont like wondering what came out of plastic tubing into my drinking water.

Water in boats can sit longer than dirt house piping, and can come from very varied sources.

5/8 flaired copper tubing passes a good volume of water at low pressure , and the copper doesnt out gas interesting chemicals.

With connections not requiring soldering , replacement , even behind built ins is easy enough.

Copper tubing is available world wide.

I like copper. My steering lines are copper. I used the type with the blue plastic coating, mostly because it looks cool, and my brother in law owns a lpg company and gets it wholesale. I agree on the unknown factor of what is in the plastic, and copper is a natural biocide. BUT, pex is so easy to use, repair, add to, etc. not to mention way cheaper. And it comes in the internationally recogniced colors of hot and cold

FF said:

I dont like wondering what came out of plastic tubing into my drinking water.

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Is there any new information on the relative safety of PEX plumbing material? - Green Home Guide by USGBC

Spent today drilling holes in bulkheads and pulling/pushing 3/4 pex thru them. I will install bolted bulkhead flanges later, gotta build them first. Everything takes SO,,,,, long on a boat. Decided against the manifold system, to many holes, to many fittings to make, to many connections, etc. Blue for cold red for hot white for raw water. all 3/4. Coulndt be easier.

Learned a lesson on large hot water lines. The larger the tube the more water is wasted waiting for hot water to get to the faucet. I have 3/8 lines for my faucets and shower and hot water is up almost instantly.

My suggested answer depends upon whether this Krogen will live in a marina or be at anchor. In a marina it can be like a house, unlimited water, unlimited energy to heat the water. The PEX and a manifold are easy to install and will reduce the connections for leaks in the future.

On a boat at anchor both water and energy are precious. While it is only small amounts you do not want someone running the water to get hot water through separate PEX lines at the bow of the boat. Better one line so that the galley and the head share the same hot water line. On a similar basis I would suggest just one 1/2" line going forward unless you have a bath tub. You don't need the flow you have in your home and the bigger line means more water sitting in the hoses and away from the water heater.

Our Krogen 42 has 1/2" lines. With a washing machine on, someone taking a shower and someone using the galley sink we don't have a pressure problem.

Marty

Agreed, it had 1/2 inch copper originally. I didnt like that it was ran thru the bilge and hard to access so decided to replumb the boat. The boat is at my home in Oklahoma right now for a total refit/rebuild. I liked the copper just fine, and the size was ok, just didnt like where it was installed. I needed 3/4 pex for the forward washdown and just decided to use 3/4 thru out. I really like a good high flowing shower, but I also understand the need to conserve when on the hook. The boat has a 250 gallon fresh water tank and a good sized 120 volt watermaker. IIRC it is a 600 GPD unit. I'm guessing that would be over 24 hours in clean blue water. We hardly ever used it. I'm sure it needs new membranes. I am planning to install a condensate/rainwater collection system and seperate tankage for the collection of it to be used for showers and toilets (I hate raw water toilets) so we can use the 250 gallon tank just for drinking and cooking. It may be several years befor this boat gets put back in the water but when it does we will be ready to cruise.

I really like a good high flowing shower, but I also understand the need to conserve when on the hook.

Sadly the US BuroRats have decided and ruled on the amount of water you can shower with.

A great flow requires far more than one single shower head.

We simply purchases a far better shower head in Uruguay , and smuggled it in our luggage.

Just as we now have medical tourism , folks have caught on that some parts of the world remains free.

Outfitting tourism??

I love it. The showerhead in my bath (in our house, hopelessly uground) is an old copper burner from a furnace that my B.I.L. removed when converting an old house over to propane. It's about 10 inches across and has a gazillion holes in it. My wife mounted it in the ceiling of the shower, which is all slate, that she also did. It is by far the greatest shower I have ever used. The water is like rainfall, and the slate is so nonslip, if you fall you are way to drunk to be taking a shower.

I drill out the restrictive passage in new showerheads. Take off the front end, you'll see the USG mandated pinhole. If it saves a trip to Uruguay, it's worth it.

You can save both the overseas trip and a trip to the tool box if you know where to shop.

http://deabath.com/Shwrcurt/Showerhd/showerhd.html

You can save both the overseas trip and a trip to the tool box if you know where to shop.

The only GPM given are the 2.5 GPM for the buroRats.

Perhaps some of the big units do not list the GPM for legal reasons?

For most folks that are not plugged into dockside water , the real question is SAVING water.

The unit used in sinks that requires hand pressure to open seems the simplest OTS low water use solution.

$5.00 at a hardware store , instead of $75 at the Yachty place.

I'll chime in here as I am a Master Plumber by trade. The manifold systems advantage is that it illiminates multiple fittings in concealed spaces. Obviously the manifold itself must be fully accessable. I am fine with running a trunk line and branches with dependable connections but if your shower or galley is at the end of this run, that first call for hot water in the morning or after a period of non use will require the dreaded wait for hot water. Sure you can run the shower for a few minutes to get hot water but if your not tied to a unlimited water supply this can be a water waisting issue. Perhaps consider running a recirculating line back for your hot water demand since you have all the tools and access points open.
Slowpoke

FF said:

The only GPM given are the 2.5 GPM for the buroRats. Perhaps some of the big units do not list the GPM for legal reasons?

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GPM is only required on new units. Antique refurbished needs no rating but takes longer to find. They start looking behind the forge then the machine shop but somehow always find them a few days later on a shelf in the plating shop. Darn stuff is never in the first place you look.

>Perhaps consider running a recirculating line back for your hot water demand since you have all the tools and access points open.<

This is common in showers where the HW is heated with a gas unit.

Turning the water off -on requires the heater to stop , then play catch up so the water temp varies.

The simple solution is to install a tub/shower control and simply plumb the tub back to the FW tank.

May cost a bit of energy , but not a drop of water.

For a power hose boat , the Euro system of returning some tap hot water to the tank via a heating towel rack is first class.