GPH of Bilge Pumps

Anything to do with Propulsion.
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onibnasir
Posts: 21
Joined: Jul 25th, 2012, 4:06 am

GPH of Bilge Pumps

Post by onibnasir »

I am trying to choose a bilge pump for my ROV. My aim is to go to 100ft. Can anyone give me a ballpark figure on what should be the required GPH of bilge pump that I should select? And on what basis have you chosen that? Like have you done any calculations? Plus what advantage does a higher GPH bilge pump offer? Greater speed or greater manuveurability?
Triton
Posts: 30
Joined: Sep 20th, 2012, 6:37 am
Location: Aigio, Greece

Re: GPH of Bilge Pumps

Post by Triton »

HiOnib,

GPH in bildge pumps stands for the Gallons per Hour the pump will throw out of the boat. So, it is a measure of thrust for the pump.
If you just use the motor cartridge of the pump (as I have done in my ROV) then I don't know if the GPH has any actual meaning.
Anyway, higher GPH means higher thrust. In my first ROV I had three 12V 500GPH Johnson bildge pump cartridges (http://www.gandermountain.com/modperl/p ... ew&i=20112) with plane props mounted that at 12V and 45m tether were very-very weak.
I used to run them at 24V, in order to give more thrust (approx. 18V reached them through the tether), but after a few dives at 20m they were burned.
I really don't know if water leaked in or if they higher voltage burned them.
I'm now using 3 L1600GPH motor cardridges (http://www.johnson-pump.com/jpmarine/pr ... .htmlwhich) which are quite powerful and able to move my ROV decently.
Yet, these cartridges are not meant for such use so there is always the risk of leaks. My new ones have lip shaft seal and I don't know if they are going to make it down to 30m. The L2200 and L4000 have mechanical seals that must be stronger, if you can afford them (along their weight which is much more than the L1600).
Sargent80
Posts: 10
Joined: Oct 15th, 2012, 6:34 pm

Re: GPH of Bilge Pumps

Post by Sargent80 »

I'm also wondering which GPH I should use. I've been thinking of using Rule 1100gph pumps for my ROV. It's only designed to go have a 100ft tether. I'm going to use a 12v power supply (probably a car battery). My ROV is a similar design to the sea fox retrofit design. So, my question is, Should I go with 1100gph pumps or 800gph pumps
derelicte
Posts: 292
Joined: Aug 1st, 2011, 3:08 pm

Re: GPH of Bilge Pumps

Post by derelicte »

buy the biggest ones you can afford.
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