Plumbing for a saltwater washdown system

[Mookie B]

I searched the archives but have had no luck in finding similar questions. Still, I appreciate any insight anyone can give me on this issue. I inherited a used Parmax pump and am in the process of installing it for use on my boat as a saltwater washdown system. I could easily throw a strainer over the side when I need to use it, but I am considering tapping-into my existing thru-hull and raw water cooling system for my engine to make for a more complete install. I will either tap from just after the thru-hull and have the pump use its own strainer or pull the water from between the engine's strainer and the engine driven pump. Here are my questions:
1. Is this even a viable option?
2. Would I need to add check valves to both sides to keep either side from going "dry" from the suction?
3. Is it likely that I would have to use just the engine or the washdown pump and not both simultaneously?
Again, thanks for any advice!

 

[Tim R.]

My previous boat came with a salt water pump to the galley sink for washing dishes. This seems to be more for off shore boats and water is plentiful where we cruise so I used the dedicated through hull to feed my wash down pump system.

My current boat has the pump and hose installed in the anchor locker and I simply drop a hose and strainer over the rail.

I would not mess with the raw water engine intake. In theory it should work fine but you are introducing more points of failure for very little convenience. Why not use the hose over the rail method?

 

[drchpete]

I agree with Tim. I would not splice into the raw water uptake and share water and certainly not with the engine running. Either drop the hose over the side, or if you really plan to use the wash-down a lot, just add another small through hull with a sea-cock. 1/2" or 3/4" should be enough. Good luck.

 

[seadaddler]

What I Did

I put a tee tap in to the salt water thru hull for the tiolet and it works just great.
Nick

 

[Ross]

Re: What I Did

I drop a bucket over the side.

 

[Mookie B]

Thanks for the advice, guys! I'm going to just drop a hose over for the time being and consider a thru hull the next time I'm on the hard. Hoping to start my slow trip from Norfolk to New Bern next week. While not a necessity, the pump should make cleaning the anchor a little easier!

 

[Bill Roosa]

If all you want to do is wash the anchor then I'd suggest you just don't pull it up all the way when you weigh it. I leave mine just below the surface for a few minutes while we motor out and that gets the majority of mud off.

 

[Tim R.]

If all you want to do is wash the anchor then I'd suggest you just don't pull it up all the way when you weigh it. I leave mine just below the surface for a few minutes while we motor out and that gets the majority of mud off.

This is not a bad idea with 3 exceptions:

1 - If you have a long chain you will not be able to motor and clean it. My 100' of chain rode holds the mud it picked up from the bottom and needs a strong hose on it while I am hoisting.
2 - My Manson Supreme holds our think dense mud very well. If there was a rough seaway I would have to do circles in the anchorage for 10-15 minutes to get all the mud off.
3 - boats with a plumb or nearly plumb bow stand the risk of the anchor striking the bow.

 

[Bill Roosa]

Hey Tim
My retort ;-)
1) only use a short length of chain in mud. Chain is for coral and coral only grows in sand which does not stick to chains
2) don't use a manson supreme in mud. Try a CQR or delta. having the right anchor for the conditions is good seamanship
3) boats with plumb bows don't ride well in a seaway and are inland boats. You should not be getting into heavy weather there in your snug anchorage or with that boat so having the anchor striking the bow is not much of a problem.