Which size bilge pump
Printed From: The Fishing Website
Category: General Forums
Forum Name: The Boat Shed
Forum Description: Discuss all things boating.
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=121776
Printed Date: 31 May 2026 at 6:37am
Topic: Which size bilge pump
Posted By: Kandrew
Subject: Which size bilge pump
Date Posted: 25 Oct 2016 at 10:25pm
| Looking to fit a new pump in my 6.0 mtr tinny. What size pump would be recommend for this size boat? |
Replies:
Posted By: Betty Boop
Date Posted: 26 Oct 2016 at 12:09am
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I'm also 6mtrs, however I'm restricted by the available underfloor height due to a 300 litre fuel tank, so I run 2x 1100 gph tmk units and two outlets from the Centre undefloor well. The two side bilge are sealed buoyancy tanks. ------------- Last week I joined an Anti-Social support group........They won't talk to me! Papamoa fi-Glass Viscount |
Posted By: widerange
Date Posted: 26 Oct 2016 at 6:57am
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Can you have too big of a bilge pump? 1 situation where big is better I say
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Posted By: Steps
Date Posted: 26 Oct 2016 at 7:50am
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Maybe... If sucks up too much too fast may tend to pick up a lot of air .. and actual water volume reduced. Would only work at full capacity if have a foot or sp of water in the bulge. Just a thought.. |
Posted By: MikeAqua
Date Posted: 26 Oct 2016 at 8:46am
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I have a 6m tinny and I have a 1,000gph TMC 'heavy duty' bilge pump as the main pump. It's on a blue sure bail float switch. The 1,000gph seems to be a good size for general bilge pump work. It will keep up with a 1 inch hole (e.g. bung left out  ) comfortably. My boat has a grid structure with limber holes so the pump is servicing the entire bilge.Each outboard produces up to 12A charge and the pump draws 6A so that seemed an appropriate balance. Also has a 28mm outlet, which allows much more water to be moved than the 19mm common on small pumps. |
Posted By: Titahi
Date Posted: 26 Oct 2016 at 11:21am
Thats defnitly one of those comments you read, that sees your head turning rapidly from side to side, finished with a hand palm to the forehead. The pump will only suck air, AFTER the water ( or majority of it ) has been pumped out..If its located appropiately and sucks air........its done its job Go as big as is practical for the space available and electrical capacity. Two is better, on seperate fused circuits..... You'd cut off and gift wrap your left nut to get water out of a leaking boat in an emergency situation ------------- "I love standing by the ocean and just knowing what its for" |
Steps wrote:Posted By: pjc
Date Posted: 26 Oct 2016 at 1:06pm
| A frightened man with a bucket can shift more water than a pump. |
Posted By: jakepitsville
Date Posted: 26 Oct 2016 at 1:35pm
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def love the float switch idea. makes for alot less hassle |
Posted By: Fraser Hocks
Date Posted: 26 Oct 2016 at 3:14pm
Wise words! These type of pumps produce very little head (pressure) so the height at which the outlet is above the water its pumping and the restriction in discharge (discharge pipe diameter) have a huge amount of influence on the pumps ability to pump out your bilge. 28mm over 19mm outlet pipe is a huge advantage and mounting the discharge point where its as low as possible, but wont take much slop back down it will ensure you minimize the impacts. Before installing your pump, drop it in a bucket of water and turn it on. Now lift the discharge pipe up to chest height. you will be quite shocked as the reduction in flow when they have some head to push.
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Posted By: Polar_Kiwis
Date Posted: 26 Oct 2016 at 4:14pm
| Biggest pump possible. The smaller the boat the more water you need to get out quickly. Advise from Burnsco friends |
Posted By: MikeAqua
Date Posted: 26 Oct 2016 at 4:58pm
You can install it so the discharge pipe runs to high point and then down to a lower outlet. This reduces head, but increases surface friction due to the longer pipe. |
Posted By: pjc
Date Posted: 26 Oct 2016 at 5:23pm
| The big question is, how much water is being taken onboard and why? |
Posted By: Steps
Date Posted: 26 Oct 2016 at 7:40pm
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Thats defnitly one of those comments you read, that sees your head
turning rapidly from side to side, finished with a hand palm to the
forehead. Well a few yrs back was messing/ using using a high volume bulge pump to establish required flow rate for a fish pond.... It was placed in an artificial stream....re circulating .. not too different to sitting in a bilge.....because it was sucking so much the water level dropped down to the point where it could not flow to the water holding area where the pump was fat enough. Was pumping a mixture air and water. Very often there are drain holes and beams that restrict water flow to the pump in many bilges.. not to dissimilar to the artificial stream... and the bilge in our boat |