installing a pump system to drain logs

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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welcome aboard.

do a search. plenty of discussions, however will summarize

pressure test and find leaks
fix leaks
remove water from logs
go boating

to remove water from the logs, I generally drop a small diameter hose in the vent down to the bottom, and when I pressure test, the hose will allow the water to be pushed out due to the pressure. usually a 3/8" diameter hose with a piece of lead wrapped around the end to give it a bit of weight. I use the little lead strips from aquarium plants.

to add pressure, I put my cupped hand over the vent hole, and use the air hose under my hand (between thumb and forefinger). you only need 2-3 psi of pressure in it while someone else uses soapy water to locate your leak.

with the water out and the leak fixed, put the toon back in the water and go boating.

you most likely have a leak where the brackets are welded to the tube. its a common problem.
 

Grandad

Lieutenant Commander
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Jun 7, 2011
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Has .Any one installed a pump system to pump out logs ??

Welcome to Iboats. I have no direct experience, but I think I would be very hesitant about pumping out water vs pumping in air to force water out as Scott has suggested. I am reminded of a nuclear plant project (BNPD "B") that I worked on during initial construction circa 1982 where someone opened a valve to drain a water system after a pressure test. Part of the system included a 12' dia x 40' (?) cylindrical tank installed vertically through multiple floors as the building was assembled. It was constructed of 1/2" (?) stainless steel. Overnight, the vacuum created as the water drained, crushed the tank like a beer can. I saw it later as it was being cut apart in pieces so it could be replaced. I since learned that this exact scenario occurred 10 years earlier at a sister station (BNPD "A"). Pontoons can handle 3 psi pressure, but if you were to inadvertently pump a 3 psi vacuum, it'll be goodbye pontoon. - Grandad
 

lmuss53

Lieutenant Junior Grade
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Sep 9, 2008
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1,227
I have an old Sea Nymph riveted fishing boat that leaks a bit, after about 5 or 6 hours afloat it will get enough water in it to kick on an automatic bilge pump in the stern. I have used it like this since I got it without ever having any problems. I just put a new Seaflo automatic pump in last week, so I am all set for a few more years.

I had a Tracker pontoon that developed the exact leaks that Scott described, along the welds at the top of the logs where the M bracket attached. I drilled out 3/8 inch holes and drained it out. I then tapped the holes with a 1/8 npt tap and ran plastic pipe plugs back in. I ran the boat like that for most of a season, draining the tubes every other trip or so. This is a very thin wall and you don't get much of a thread in it, but it held for most of a year. I got the boat fixed the following year under warranty and the dealer put half couplings on the logs to put brass plugs in at that time.

I told both stories because I think the second method is a reasonable temporary fix for your problem. The permanent fix is a trip to the welder.

I also don't see any reason why you couldn't cut a small window high on the rear of a log and drop a wired auto bilge pump in to pump out the accumulated water. I won't pretend to be a pontoon builder but I saw the inside of a few that were opened up to shorten them and they have all been the same in a few ways.

They all had chambers that were walled off all the way from the top down to ALMOST the bottom, with a small gap to let the pressure equalize and let water in one section drain to the rear but to keep the chambers from all flooding if one suffered a major breach. The were also all vented to the outside in some way in at least one of those chambers. to allow for the changes in pressure from cool to hot as mentioned above. As they were constructed the only chamber that could flood completely would be the one with the breach and the one with the vent.

I don't see any reason why a bilge pump, dropped through a small window cut in the rear of a tube, and then pumping back through a thru hull fitting in the window cutout, wouldn't work just like the one in my Sea Nymph. You would have to pop rivet some pieces to the cutout section to allow you to put it back in but it should work. I would bet anything you want that water entering anywhere on the tube will find it's way to the lowest point in the tube eventually, just like my old Sea Nymph. That point is most likely the lower rear of the tube.

I thought of doing it with mine before I got it fixed but the drains were a much simpler fix. Just like someone with a leaky old boat who uses it all the time and pulls the plug out at the end of each trip.

I would never try to pump out a tube by putting air into it, I have heard too many stories of people blowing them open with low pressure, under 10 PSI. while trying to leak test them. I've seen pictures on other forums from manufacturers who showed the ripped open tube that resulted from someone mistakenly putting 15 PSI of air in a tube being tested, instead of 3 PSI

I would also make sure the tube was vented, high in a dry spot, if I put in a pump. but I don't think the little bilge pump would collapse the tube if it started to draw down a vacuum, it would more likely just lose it's prime and stop pumping.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I also don't see any reason why you couldn't cut a small window high on the rear of a log and drop a wired auto bilge pump in to pump out the accumulated water. .

because the toon log will fill up with water if it is splashed over the top and the toon will eventually sink.
 

MinUph

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Jun 5, 2011
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466
Seems to me pontoon logs should have no open venting anyplace. If you were to put a bilge pump in one where would the air come from to replace what is being pumped out. If you allow for "ventilation" to accomplish this you will be opening a hole in the log. Get it welded by someone that does this for a living and be done with it. Make an appointment and it shouldn't take long.This is not a v hull with an open bilge.
 

lmuss53

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Sep 9, 2008
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1,227
It is vented, never saw one that isn't, and I look at a lot of pontoon boats, I have a fishing buddy who owns a repair shop and I spend a lot of time there. Walk up to any pontoon boat and look at the tube up at the top under the M bracket, they are there. Some look like plastic plugs but have a vent hole hole in them. My Forester has upside down J tubes that let air out and in but not water.

BTW if someone comes in with water in a tube my friend sends them down the road to the trusted local welder who fixes them everyday. That is the appropriate fix for water in the tube.

If you did find a pontoon without vents you would have to put one somewhere in the tube, high and dry like I said.

I'm not leaving the window open, I'm going to put it back in like the restoration guys patch an aluminum hull, Now I have a hull like any other with a small leak somewhere and a bilge pump. Water leaks in slowly, pump pushes it out slowly, air comes in the vent slowly..

The drains are an easier temporary fix, but the pump is do-able.

I'm not saying it's something you should do, just that you could if you wanted to.
 
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