Scottar
Nothing pumps more water then a man in a manual pump shit scared watching water levels rise as his other pumps have failed
The wiring wasn’t long enough for my crusicraft from the cavity they were in
Never the less for any joins you should use epoxy filled heat shrink it just works so much better
Or your saying the extra $3 isn’t worth it
Not at all mate - well better than normal heatshrink but it will still let moisture in. Seen it many a time. All joins regardless of how they are sealed should be secured above the height of where any water will be.Originally Posted by stevej
Agreed, dual wall used to be better than it is now. I use normal heat shrink first then follow it by and extra long length of dual wall, can be challenging in short lengths.
As for the manual pump - bucket is the goto for me. Have you measured how much fluid you get per stroke?
Generally, I put in the biggest pump/s that are available within reason, all my recent boats have had the 3700G/hr units. My 26ft had 3 of them. 1 at the bottom of the bilge floor level and 2 halfway between the bottom and the deck floor level, all wired with automatic float levels and directly to the batteries.
My reasoning is as follows for having very large pumps;
From what I know, most pumps are usually rated as follows: if it is a 500US G/Hr pump (2000L), (sounds like a lot but it isn't) then it has that rating at a horizontal hose level, which in real terms means nothing as most hoses usually go up between 400-600mm above the pump, you should find out what your pumps will pump out at the height of the hose outlet, which also is dramatically much lower than its stated capacity and falls off extremely fast the higher the outlet is. So in effect 500G/hr at 600mm might only be about 1/3 of the rating (as an example) divide that by 60 for gallons per minute and again by 60 for gallons per seconds, and that is all you could expect in an emergency. ie: 170/60/60=.047G/sec or 0.178L/sec. That is fine for getting rid of a bit of rain going in to the bilge or a very slow and light water leak. In the event of a big fast leak you have no hope of getting rid of water fast enough, in an emergency such as a bit of a small wave going over the side in to the boat, which could dump several hundred liters+ into your boat in a second or two.
Using the above theoretical example and 200liters from that wave on board that would take your 500G/hr pump and (approx 200L seawater) with 0.0178l/sec discharge and the end result is it will empty your boat in about 3.12 hours! (This is assuming my maths is correct). Generally if you took such a wave over the side it would mean that you either did something pretty stupid or else the seas are pretty bad and chances are that you might actually get a second or third wave very shortly afterwards, this is assuming that the boat can handle an additional couple of hundred kilos weight sloshing around each time and doesn't list horribly compounding the problem as water will rush to the lowest side of the hull. So if you can wait 3.12hours great......., but I don't like your chances of staying afloat for very long in a rough sea unless you have a self draining deck floor.
Now as I said before this is just an example and the bigger the pump the less time it will take to pump out the water, downside is that you need a bigger battery to cope with the extra amperage drain that large pumps use, which in the case of the 3700G/Hr pumps could be 20 amps, but to put it into perspective, I would rather have drained the battery quite a bit and be upright with an empty hull than be submerged and have a fully charged battery and a small pump!, all the wiring and fuses should be waterproof. Only time the automatic float switches won't work is if the boat is upside down and then it is a moot point anyway! Large bilge pumps are like insurance, usually you don't need them, until you do.... and then you want the best (biggest) one available.
This is just my take on bilge pumps so some others may disagree.
Can’t use a bucket while driving on your own with a leak etc
Each of us can piss back and forwards on why something is better or not
It’s not until you need a safety device such as additional pumps that their importance can be gauged
Also with the wiring ,can have that view that all joins should be above water line but not all boats allow that to be possible
Tinned wiring as short a length as possible
Soldered joint
Heat shrink to cover joint
Another layer of heat shrink half inch to a inch longer either side of the first one
Any eye terminals I fill with solder and run the epoxy heat shrink as far down as possible
One other consideration with bigger pumps is they're physically much bigger, on my last boat I couldn't get the 4000gph pumps into the bottom of the bilge so had them mounted higher for emergencies and a 500gph was the biggest I could fit right in the bottom to tidy up the rest.
Thanks guys, all comments have been helpful.
I have a big bilge area exposed at the back, as well as another 500 under the floor, so size wont be an issue.
Getting some prices now and also tomorrow measuring the height I will have to go, to fit the hose out point, then looking at amp draw, I think the 1500GPH draws 4.8 amps.
So upon return from my belated "Xmas" holidays, I'll be fitting off the back area, filter, fuel lines and Bilge pump etc, That will be another job down, but plenty more to go.......
cheers
Col
All good Steve - just be aware of the things shortfalls - use it regularly - if they sit too long the diaphragms can go hard and crack and make sure the pick up is screened. Like all diaphragm pumps they rely on valves. If you get crap in the valves they will not work. I am well versed in stripping down pneumatic diaphragm pumps for this very reason as we use them for pumping bilges at work. As for me - I don't tend to fish alone these days but my rig has an autopilot so if required I can drive and bail without issue. Let's hope neither of us ever have to worry about it. I've had a couple of goes in previous boats - once through not having an auto switch - felt water splash up the back of my legs as I came down off a big wave and once through a shoddy pump installation in someone else's boat combined with a failed pump - pulled the bungs to get rid of that lot.
As for the join - it doesn't need to be above the water line - just out of the wet area of the bilge. This can be as simple as screwing in a few cable tie mounts to the underside of the floor in a tinny, mounting it up high on a rib etc - or worse case scenario cable tie it or sika it to the top of the pump - just don't leave it lying in a wet bilge area. The glue filled heatshrink is ok but in a constantly wet environment, water will get in eventually. If you have joins that are permanently at a positive potential - such as those on a float switch - lying in a wet aluminium bilge which via the outboard is at negative, not only will the corrosion in the cabling be accelerated but there is a very real chance of causing electrolysis in the hull - I've seen it - I fixed shoddy shit like it for a living for 20 years. Another issue that can arise in pressed tin boats is that the wires can get caught between the ribs and the hull sheet as they move and get pinched. I also know from my time doing this that keeping water out of a cable join is exceedingly difficult. We tried glue lined heatshrink, rubber self amalgamating tape, multiple layers etc on joins in trawler tiller flats on autopilot rudder sensors, which while not necessarily being underwater were subject to vast amounts of humidity and leaks. It was far from uncommon to have to attend some time later to replace cables.
I've had a lot to do with bilge pumps in commercial boats, and found a few pitfalls. Firstly, the joins should be above likely water level. Seen plenty of ordinary joints done that resulted in the positive connection corroding off. One of the boats I deckied on, we found it sitting on the bottom one morning-luckily the tide was out, and it was on the keel , stopping it from going any further. Positive joint has failed. These larger planing hulls all had a keel space, could be quite deep. Usually plated off on ali huls so that the aft section might be a 600-850mm deep. Shaft gland in there, electtric pump and pickup for motor-driven bilge pump down there. Glass boats were normally not quite as deep, depending on whether their keel was laid up or bolted on. You always had water flying around in there when steaming, as your gland had to allow enough water in the cool the shaft. This usually meant a steady drip when you stopped, could be a trickle if left unattended. Normal practice when moored for the day was to pump the gland full of grease. Get a bit slack with keeping the gland packed, and/or forget to grease, they were always making water.
When I got a boat myself, found it with a lot of water onboard one morning. Again, positive connection corroded off. So, knowing the tails on the pumps--usually Rule 5000gph with separate auto switches, were not long enough to get them up to a really dry area, I used a thin slicon nozzle to fill 75mm of heatshrink over the joint, then shrunk it to force the slicon right through and have it come out either end. Sticking with that, I never had another problem in that regard for my next 20-odd years of skippering. Just remember to leave the pump in auto.
I was out in the moorings one morning checking on my boat in the off-season, before it went on the hard, and noticed that another local boat was showing no waterline. It was a 57ft Randall, big boat for its day, twin 8v92's. I knew the owner was away, and we didn't have mobile phones that we carried, so I jumped on board and found it pretty full. Bilge pump was off, not auto. Turned it on, but it really didn't seem to be making a difference. So I had to trace the plumbing, arms-length deep, and work out how it pumped from the manifold. our setups all had a changeover valve setup so you could pump sea water to a deckhose or tank, or pump out the bilge. I worked it out, crossed my fingers , and started the motor running the pump. It was getting critical, as the water was very close to overtopping the batteries, and the lower run of the pump belt was flinging water.Anyway, I had guessed right, and she eventually pumped out. I found that one gland was dribbling, and the other was pissing. Fingers got pointed at the crew who had been tasked with looking after it.
So, short story, keep it dry by whattever means. I've used a lot of glued heatshrink in my time, up to 100mm heavy duty stuff--it is very good for general weather resistance, if applied correctly, and certainly heavy splash-proof. If it is a joint that is likely to be submerged, even for short periods, on a regular basis, such as trailer wiring, I still stick with the silicon inside the heatshrink thing.
Yes, the bilge manifolds on some commercial boats almost need a degree to figure the bloody things out. Not a great situation on a boat your unfamiliar with - not to mention underwater - good work. Hope it earned you a carton or two. The silicone certainly will work - I've used it for splicing repairs on transom mount transducer cables that have been damaged. Biggest advantage is that it retains some flexibility whereas the heatshrink tends to harden IMO.
Just a best practice question,
Installing bilge pump and float switch in the bottom of the bilge. I would prefer to stay away from fibre glassing a patch down at this stage, So I was
thinking of cutting a piece of flat aluminium to the base size of the pump and float switch, marine Urethaning the flat aluminium piece down to the bilge floor
then screwing the bilge and float switch to the flat aluminium, ?? comments.
Also, I was just measuring the height for the hose above the actual pump, I understand the higher you go, the less efficient the pump becomes. The engine well above if I put the outlet there, would probably be around 450-500 mm. However, I have found a hole, I always new it was there, underneath the gunnel rubber, which has been filled up ( previous owner ), which got me thinking, height from pump would be approx 650mm and it would be a bigger distance, but there would be less bends and I could secure the hose up higher on the inside of the transom out of the way, I think. the existing hole must have been for some type of water escape, currently its only about 18mm, so I realise I would have to enlarge it. currently I have an 1100 rule pump and all fittings including wiring pipes and control switch on hold, I could increase the size of the pump on the order.
Thoughts ?
Col
If you go to the engine well, the hole must be above the height of the transom lip that the engine sits on or the hose must at least go up higher and then back down to the outlet. How do I know? One of the previous events I mentioned was exactly due to this coupled with a wind against tide situation that saw us fishing with the stern into chop that was big enough to break over the transom lip into the well - basically meaning the well was full to capacity constantly. The outlet port was below the water level and the hose ran straight down to the the pump - and filled the boat to near floor level before we noticed. The other hole would be fine IMO. The aluminium will work no worries but after a while, getting the screws out will probably be a right mission due to galvanic corrosion if anything needs attention. Also make sure you mount the switch higher than the pump.
Hi Scott, "Mount the switch higher than the pump"
I understand the theory of that, I actually thought that I read, that the minimum level the float switch activates, was pre set, which If I mounted
Both on the same thickness piece of aluminium, it should be alright. Something rings a bell that the float switches are set to activate at a water level
of 50mm,,,, I'll re check that.
Isn't it horrible when you notice water has somehow got in and you've all of a sudden got an issue LOL. The engine well is quite high on the inner side, compared to the outer and I have also lifted the transom to a 25 inch, as I always had issues backing up with the old 20 inch transom and a couple of big blokes standing at the back.
I'll look at routing it to the existing hole in the hull outer skin, it was probably more the distance I was concerned about and the extra height, but to fix the exit pipe high up above the batteries really would get it out of the way and eliminate sharp curves.
Because of the extra height and distance Scott, would it be prudent to go up in pump size, just to cover the extra height and distance. ???
Unfortunately, our belated Xmas holidays are happening tomorrow, having 2 weeks up Port Mcquarrie, really looking forward to it, with a couple of charter days organised, with the approval of her in doors, but a bit frustrating as far as the boat fit out goes, just when I'm ready to get get back into it again !!!!!!!!!
Col
If you don't mind spending the extra and have the room Col, more capacity isn't going to hurt. The main thing with float switches is that they turn off before the pump starts sucking air. I've seen a few where due to the angle of the hull and the switch being mounted closest to the keel, they would simply keep running or cycling. If the tolerances are too tight, just the water flowing back down the hose when the pump stops can be enough to switch the pump back on again. Normally in a trailer boat if I have my pick of outlet locations, I go just below the gunwale rubber on the helm side (assuming the boat doesn't have a downturn in the rubber that brings the outlet too low). Main reason is so the skipper can turn and see at a glance if the pump is functioning without having to leave the helm when the pump is switched on.
The water coming in was an issue..........but not quite as much as the pump failing about 10 seconds after it was turned on due to debris and an incorrect fuse size. It was at this point we pulled the pick and I leant over the duckboard and pulled a bung under power to drain the hull.
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