washdown pumps

redneckpunk

Petty Officer 2nd Class
Joined
Nov 19, 2008
Messages
130
Im looking to install a washdown pump kit on my 19ft "tinny" project and looking for feedback since I've never had or used one. Question is, primarily which size? The 3.5gpm pump has a 1/2 hose with 70psi max. The 5.2gpm has a 3/4in hose with 70psi max. Both have 25ft hose. The boat already has through hull fitting and hose that was orig set up for rear livewell but the pump was bad and I'm removing the livewell box. So what I'm seeing is the biggest difference is the amount of water (gpm) as max pressures. I havent measured the line diameter coming in, and perhaps that make a difference, but could that easily be be adapted with a 1/2-3/4 coupling or visa versa? Like I said, these pumps are new to me so any help would be appreciated as I cant see spending the additional $50-$100 for the "bigger" pump if its not needed.

~RNP
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,019
Re: washdown pumps

When and if you install one inline on the thru the hull fitting I would recommend a ball valve between the pump and the motor.

The smaller pump will do fine and you only are using it in a 19' boat. It is for wash down not fire fighting. The lower pressure will be fine.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
Re: washdown pumps

Pump ratings are no different than speed ratings in an automobile. Is a 100 mph car better than a 90 mph car when the speed is limited to 45 mph? ;)

I have a 3.5 gpm @ 45 psi washdown that is more than adequate. I have 10 ft. of a 5/8? garden hose on it.


The bigger issue is longevity and the ability to run dry.

FWIW: A 1/2" ID hose will generate 3 times the prssure drop of a 5/8" hose at 5 gpm. Keeep hoses as large as possible and as short as possible.
 
Top