Bilge Pump Hole

[New_fisher]

Gday Fellas'
I have just invested in a bilge pump for the rhino as she has false floors which make bailing a problem, the only problem I have is where to put the hole through the skin of the boat? :-/ On the transom or the side of the boat? - I thought if I put it on the side, then I can see when it's working, but it's clear tubing anyway, so I will be able to see regardless.

I didn't want to put the hole too high as it means the pump will be pushing a greater head of pressure, although too low and water might come back up the tube? Dunno, I thought maybe just higher than cutout in the transom for the engine.. Any thoughts, thanks fellas, Hurlz ;)

[Fishinmishin]

On the side well above the waterline is my opinion.
Cheers, Jay

[finga64]

I put one on the side above the motor well cut out. Works fine
see link to other thread for picturehttp://www.ausfish.com.au/cgi-ausfish/yabb2/YaBB.cgi?num=1129883249/0

[bazzacuda]

Hurlz,

This post is a bit longer than average and some people find long posts a pain, I hope you find it useful rather than tedious.
I'm presently putting a Johnson L120 bilge pump that I bought on sale at a local chandlery some time ago into my 5m project boat so I'll use my arrangement as an example and you may find the answer to your question in that.
This pump has a choice of 2 hose fitting sizes 1 1/8" dia and 1 1/2". The smaller diameter hose will pump 100 l/min and the bigger one 120 l/min. But as I understand it, this is through a straight, that is ‘horizontal’ pipe.
Pumping up to a 1metre head, these figures are reduced to 80 l/min and 100 l/min. The maximum head height for this pump is 3.5metres.
If I had a smaller pump I would be tempted to put it over the back of the boat to reduce the head height and increase the volume. and I think there are a number of ways you could minimize the amount of water this lets into the boat.
The head height in my boat, if I put it through the side and a little forward is only 600mm so I think that using the bigger diameter hose, I will be able to pump over 100 l/min out the side of my boat #So this is the position I would prefer for the outlet on my boat. When I look at the boat, it would have to have the back ½ almost submerged for this to act as an intake rather than an outlet.

But the underlying issue to the installation of a bilge pump is about what you (and I) are trying to achieve. I think there are two different scenarios. I’ve only ever owned two boats and they illustrate the two different situations nicely.
Scenario 1 : 5m project boat. When I bought the Johnson 120L pump the shop owners, were “serious boaties” – lots of real on water and blue water experience. This one bloke gave me two pieces of advice – (1) tin boats don’t float. You would have to put in so much Styrofoam that you couldn’t move to make them float. (2) the majority of bilge pumps sold with or installed in boats today are effectively useless, - you can p—s faster. He said, get the biggest pump you can afford (which in this case was a big pump for very little money). With reservations, as you will see below, I accept his observations.
Now my project boat is a rather old (1980) hull made of 2mm aluminium. With age and resulting corrosion, there are sections that are about 1mm thick, if you don’t count the paint. This is a bit like going to sea in an alfoil basket. The objective for the bilge pump in this boat is, in the event of a serious hull problem, a split or a hole, to pump out water fast enough to enable me to gain the nearest landfall. At 100+litres /min (as long as the battery lasts) that about the best I can do.
Scenario 2 : I have another boat, a 3.9m HD Stacer. I bought this boat at the end of the 80’s from a bloke in Mackay (long since dead) who used to troll for mackerel out beyond Slade and Round Is. #Among other things he had it set up with a baffle around the back of the low cut back of the boat – sort of like an engine well, and had wired in a little bilge pump on a hold down switch. #I found all of this stuff a bit of a nuisance and removed it. It wasn’t until many years later that I found out how useful this rig was. #I caught a big flathead on the southern sand bank approaching the bar at Jumpinpin and I was so busy with the fish that I copped a wave over the back of the boat. It was no real drama but I had a floor in the boat , and while I could see some water in the after section I couldn’t really bail it out. #Of course, the problem was clear when I started to power the boat up for home, all of a sudden the boat was nearly vertical and I was looking at the sky as all the water under the floor rushed #to the back of the boat. There was nothing else I could do other than motor carefully back to Jacobs Well. A long trip. #I wished I’d left that bilge pump in place then. Which illustrates the condition under which even a small pump has its place.
I hope all this has been of use in some way
Good luck and tight lines
Barry

[New_fisher]

Thanks a lot guys - esp. barry. A lot of good advice, :)
I think I will position the pump just above the height of the cutout, cause if the water is coming back through the hose at that height, I will have more to worry about than a few cups through the hose - like the 2000litres that are now in the boat and flooding past the engine. Does it matter whether I put it on the side or the transom, I don't mean to be a pain, but I can't undrill a 50 mm hole!!
Thanks boys,
Hurlz
;)

[Heath]

Bazzacuda,

Getting the biggest pump you can afford is the right advice. However getting the biggest cheapest pump you can afford is not so correct. IMO Johnson pumps simply do not cut it. I would return it if able and get a Rule.

My boat is just shy of 3 year old & i'm about to replace my 4th johnson pump :-/ ( I have 3 pumps in my boat )

[blaze]

I didnt want a hole so I routed the clear pipe along my steer cable and then put a couple more zip tires around it so it went down the outbourd mounting bracket so it was lower than the back by about 3 inches, never had a problem.
cheers
blaze

[bazzacuda]

Thanks Heath , that is concerning.
Once I have this pump in place it's clear that I should test it thoroughly.
Under what circumstances have these pumps failed - I can use your response to frame my tests.
regards
Barry

[bazzacuda]

Hurlz,
it's a bit late in the night and I'm a bit "sleepy" but 50mm, ? what connections are U using. My 1 1/2" pipe only requires ~40mm drill. check 3 times before drilling.
Other than that, put it through the side, all the new Quinnies do it, it looks neater and I think the sea can't get to it so well. IMO
best wishes
Barry

[Heath]

The Johnson pumps seize up. I replaced 3 of them in the first 12 months. One also had the housing crack as well.

To get them going again you either have to give them a tap or pull the pump out & manually turn the impella a few times to free it up. Oh also forgot to mention that on one of them that seized up, I got a belt off it when I touched it. Water in the motor as well. If you have a look after a few trips you will see the shaft start to go rusty. Once that rust gets to the O ring, it allows water into the motor windings. No such problem with my Rule pumps.

[finga64]

I agree with Heath. I've had 'concerns' with the Johnsons