long run seawater hose

Hi all,

I have a sea chest aboard my boat and I'd like to use it to supply seawater to a head located about 30 feet away. It's an electric head and I was planning on installing a vented loop close to the sea chest and the seawater pump right after that. Is this feasible or should I instead install another sea cock closer to the head? (I'm trying to avoid unnecessary holes in the boat.)

If it is feasible what kind of hose or pipe would you recommend? I was thinking a hard pipe might be better (with a flexible hose where it passes through a bulkhead and where it attaches to the pump and the head.)

I'd also like to supply seawater to a foot pump in my galley. Could I use the same intake to supply that pump? I was thinking to install a no return check valve close to the head to avoid any cross contamination. Or should I use a completely separate line?

Thanks in advance for your advice!

 

Pex grade A or Uponor

I prefer working with Pex on brass fittings, but Uponor on plastic is better for corrosion concerns. Uponor is so much harder to use and really requires better and costlier tools for a small run like yours and always a concern for small spaces for all, so think ahead..

 

I've done some fairly long runs but nothing 30 feet. We have an inordinate amount of hull perforation with our chilling equipment, deck washdown pumps as well as house systems. On my last boat we did some consolidation on a retrofit. Found that upsizing on the common feed line allowed us to have two relatively high use pumps simultaneously with minimal issue. We had initially tried check valves but they rather quickly had issues, we swapped to swing gate check valves but even those had occasional issues sticking and we found that a 2 inch pipe feeds a 1.5 inch deck hose and a 3/4 inch deck hose just fine.

I use a Trident wire reinforced hose, it's not cheap but for below water line applications we get life spans measured in decades. Issue would be on a 30 foot run its liable to cost more than a seacock and thru hull.

 

Yes, it’s feasible to run seawater from a single sea chest 30 feet to your electric head. Install a vented loop near the sea chest, and use mostly rigid marine-rated pipe with flexible hose at bulkheads and connections to the pump and head. You can also supply the galley foot pump from the same intake, but install a check valve near the head to prevent backflow. Flow might be slightly reduced if both are used simultaneously, but for low-volume draws it usually isn’t an issue. Separate lines are only necessary if maximum flow or independent operation is critical.

 

It's feasible but you need to be using that head regularly. If the seawater sits in the hose, it starts to stink. Even with a short run here in the tropics it doesn't smell great at first. You get used to it. But 30 feet on a hot day after being away from the boat for a couple of days... I guess it's electric flush but it is still unpleasant. Maybe you aren't in the tropics and aren't planning on going there?

 

The vented loop should be close to the toilet.

 

Get rid of the sea organisms with a fine filter at the outlet of the thru hull.
Had same problem on my boat with a 6 foot hose. Tiny seal life dies in the hose and boy does it stink.
After using a black plastic filter with clear plastic bowl and a SS fine mesh filter, NO MORE STINK.

Filter has 1/2" NPT threads, and is meant for filtering water I think for electric water pumps. I bought it on EBAY.

 

Amazon.com: 1/2" Female NPT in-Line Strainer with 60 mesh Stainless Steel Filter Screen (1/2“ 60 Mesh) : Industrial & Scientific

 

How is that filter keeping bacteria from entering the hose?