Live bait tank on transom?

[MattInOz]

Hey guys

I'm at a point where I'm wanting a live bait tank on my boat, but my 14' runabout's already crowded enough with two of us and our gear. I'm also paranoid about pumping water into the boat, would rather it all remain outside the boat in case something goes wrong. I'm thinking of getting an alloy one (expensive!) and mounting it on the outside of the transom to the starboard of the outboard, and putting a pump & pickup on the port side where the boat already has a bracket that originally had the speedo pickup mounted on it (it now has a GPS speedo, so no pickup). Don't want the tank on the port side coz the swim step's there.

I found a design I like online (I'll link to it below) but I'm hoping my local welder guy can do it for me cheaper and I'll reduce it to 350mm wide and maybe a little shorter, bringing it down to about 20 litres. I'd also get some aluminium C section welded to the transom so I wouldn't have to put holes through the hull, and probably use stainless pins & R clips to mount it so I could remove it easily.

So, any reason I shouldn't do this? Anything to watch out for? Any better ideas?

https://www.prowave.com.au/store/live-bait-tanks/transom-bulkhead-mount/live-bait-tank-transom-mount-38-litres/

 

[ellicat]

I think what you're after will work. If you're getting one made, I would put an edge around the sides and back, like the ones from Baitmate ( https://baitmate.com.au/ ) Stops things like knives/sinkers etc rolling off. A must imo. You would need a drain hole at the back somewhere, too.

[MattInOz]

8 minutes ago, ellicat said:

I think what you're after will work. If you're getting one made, I would put an edge around the sides and back, like the ones from Baitmate ( https://baitmate.com.au/ ) Stops things like knives/sinkers etc rolling off. A must imo. You would need a drain hole at the back somewhere, too.

You mean to use it as a bait board? Hadn't thought about that... already got a big bait board mounted over the outboard (new since you saw my boat) so prob not needed.

Would definitley put a drain in it too... no reason to burn fuel lugging 20kg of water round when I don't have anything swimming in it.

[ellicat]

Ah yes, I was thinking of using it for dual purpose. I have a Baitmate livewell/bait board on mine. Magic. Also leaves the side free to run rods when trolling.

Might be worth thinking about.

[MattInOz]

18 minutes ago, ellicat said:

Ah yes, I was thinking of using it for dual purpose. I have a Baitmate livewell/bait board on mine. Magic. Also leaves the side free to run rods when trolling.

Might be worth thinking about.

Yeah I really do love the idea of them, but it'd stop me raising the outboard. It currently lifts up directly under the baitboard and even lifts it half an inch or so at full tilt. Was sure I had a pic of it on my phobe but it looks like I cleared it out.

If this tank works out the way I'm thinking it won't interfere with trolling... it'd only come up 1/2" or so above the gunnel... just enough to open the lid.

[ellicat]

Yeah, seems your original idea would suit you best.

[Alex2505]

Hi Mattinoz,

 

i opted for the same set up on the polycraft. the tank was made by Fraser Coast plastics have a look on there face book page. the pickup puts water in the tank as you travel. and the pump can run when you are at rest. no plumbing inside the boat all screwed to the rear transom. overflow drains out the top of the tank.

[Alex2505]

This is the setup below

 

[MattInOz]

23 minutes ago, Alex2505 said:

This is the setup below

 

Looks good, very similar to what I want... exactly the same pump/pickup I had in mind.

 

Home now and had a chance to look at the boat... seems the transom isn't flat, it has some creases in it for strengrh. Will have to have a rethink... maybe some sort of stand offs so the tank has a 1" gap to the transom.

[Ed.]

The only thing I can think of, is that extra 20-25kg weight on the corner outside your boat on the step going to effect your boat trim and balance? If you do go ahead with, it another possibility is to add a float switch just above the transom bottom, so when on the plane, your pick up will still put fresh water into the tank and the pump will switch off but the water will keep on filling the tank, when you slow down and the boat sinks a ,the float will activate the pump automatically and continue pumping sea water into the tank.

Plus add a valve between the pump and the tank so you can stop water going in to the tank when you just want it empty.

[MattInOz]

3 hours ago, Ed. said:

The only thing I can think of, is that extra 20-25kg weight on the corner outside your boat on the step going to effect your boat trim and balance?

Yeah that's something that concerns me some too. I already have two batteries in the stern, one either side, so adding 20kg of water would be about the same as adding one more large battery. It's not going to sink me... but it's something to keep in mind. Unfortunately I don't really have anywhere else to put it. Fortunately however it's somewhat offset by the electric anchor winch mounted in the anchor well up front. I don't have trim tabs, but any effect the tank has can be remedied by moving eskies etc around. 

3 hours ago, Ed. said:

another possibility is to add a float switch just above the transom bottom

That's actually a really clever idea... will look into it. No point running the pump when the boat's moving, but if I manually turn it off there's a good chance I'll forget to turn it back on again... and then I'll have deadies instead of livies.

3 hours ago, Ed. said:

Plus add a valve between the pump and the tank so you can stop water going in to the tank when you just want it empty.

Good point. I'm putting a drain on the tank of course but if I don't have a valve in the hose from the pickup the tank'll keep refilling every time I move the boat. I did see a pickup with an adjustable mount so you could set the height... but it didn't have the plate for the pump, and trying to lean over the transom to adjust the height to disable it would be a pain. Valve's simpler.

[ellicat]

6 hours ago, MattInOz said:

Good point. I'm putting a drain on the tank of course but if I don't have a valve in the hose from the pickup the tank'll keep refilling every time I move the boat. I did see a pickup with an adjustable mount so you could set the height... but it didn't have the plate for the pump, and trying to lean over the transom to adjust the height to disable it would be a pain. Valve's simpler.

I have a quarter-turn tap on the hose (that enters on the side),

[MattInOz]

4 hours ago, ellicat said:

I have a quarter-turn tap on the hose (that enters on the side),

Does your "fill" hose enter the tank at the top or the bottom of the tank?

I've been trying to decide how to do it. My thinking is that spraying through an aerator at the top is popular as are aerating air pumps but realistically you'd lose 90% of that air and if tye water entered at the top you'd end up with a lot of "stale" water at the bottom as the "new" water would just flow out the overflow. If you're pumping in fresh sea water it should be plenty aerated on it's own, the more important issue is replacing the water contaminated with fish waste products. I think aerating heads, pumps etc are really only needed on a closed circuit system with no fresh water supply.

Of course a bottom entry would require a non-return valve too, or your livies would quickly end up deadies.

[mangajack]

Your inlet should be above the overflow.....it also aerates the water dropping into the tank....have the overflow at least 50mm below the inlet so your slop does not wash your live baits out of the tank.

If you are getting a custom build done, get a pickup tube fitted to the bottom so as you travel you have fresh aerated water entering the tank....(this will need a small check valve fitted like a scupper)....if not you must also have a bait aerator as well because the pump feeding the tank will be out of the water when travelling.....I would mount this pump onto the side of the tank between the motor and the tank to minimise plumbing to fail. Your overflow pipe will need a screen on top and a suitable size to drain the water that can be pumped into the tank without increasing the level. i.e. if you have a 350gph pump your drain will need to drain at least 400gph as an overflow.

[ellicat]

3 hours ago, MattInOz said:

Does your "fill" hose enter the tank at the top or the bottom of the tank?

Filler at the top. overflow underneath, drain in the bottom.

[mangajack]

FWIW my drain is in the bottom...my overflow is a bit of conduit with a grate on top that plugs into the drain fitting tightly....the height of that tube is about 50mm under my inlet height. To drain the tank I simply pull out the tube.....no need to a bung or a valve.