Making a tuna tube

captjim · Jul-02-2007, 02:51 AM

I received a PM from one of our members asking about building a tuna tube. I decided to post my version for all to see.

I copied the design from Capt. Jeff Rogers and made a few modifications to make it a little sturdier. Jeff was happy with the modifications.

You will need a 3 to 4 foot length of 6” schedule 40 PVC or ABS plastic pipe. A cap to fit on top, a 6” diameter plastic funnel which will slide into the pipe where it will sit in the bottom of the tube (ACE hardware has one that fits perfectly inside the tube) a “funny pipe” sprinkler offset, a tube of silicone sealant and some CA glue or epoxy glue.

The measurements will have to be determined by the configuration of the boat and the potential size of the baits to be stored. The place and method of mounting the tube is left up to you. I mounted my tube on the swim platform so the discharge pours directly into the ocean and the top of the tube is about 4 inches above the stern for easy access. If this configuration will not work on you boat, an overflow tube will have to be created to discharge the water.

Cut a section of the 6 inch pipe about 3 to 4 inches long. Then cut a lengthwise section out of the pipe about 1 inch wide so that when the pipe is squeezed, it will slide into the long pipe to create a shelf for the funnel to sit on. Don’t glue anything yet.

Next, borrow, beg or steal a ½ in. pipe die to cut some threads on the bottom of the funnel so the funny pipe fitting will have something to bite into rather than relying just on glue. It won’t be holding much pressure so it doesn’t have to meet “code”. Take the funny pipe hose off and set aside. Screw the fitting onto the funnel after applying epoxy or CA (super glue) and set aside to cure.

Next drill a 1 inch hole about 4 inched down from the top of the tube. This will be the overflow. The hole size is critical. Plan ahead to determine the direction of each hole.

Compress and slide the shelf into the bottom of the tube. The distance from the bottom of the tube to the top of the shelf should equal the height of the funnel and the offset fitting plus 1”. Mark the spot. Slide the shelf up a bit (about 1”) and smear some PVC cement or epoxy onto the tube and then quickly slide the shelf back into position.

Place a bead of silicone onto the top of the shelf and slide the funnel down until it beds into the silicone. Tape it or weigh it until the silicone cures and is now fastened to the shelf. After it has cured, turn the tube over and use the rest of the silicone to coat the whole underside of the funnel, especially where it meets the shelf at the top of the funnel, to add some stiffness to the funnel. Neatness does not count.

After the silicone has again cured, sight and then drill a ¾” hole in the side of the tube so the delivery hose will connect to the barb on the angle fitting when it is put into the hole.

The cap for the top will be too snug to remove so the inside will have to sanded out until you achieve a sloppy fit. I am fortunate to have a wood lathe and I was able to do this quickly. If not available, elbow grease!

Drill some air-holes into the top so you won’t be fighting suction when removing it. Drill two opposing holes at the top about 3 to 4 inches apart and insert a short length of rope with knots tied at the ends to act as a handle.

Run some 1/2 hose through the bottom hole to the barb of the funny pipe and run attach the other end to your pump. The pump must be able to put enough water into the tube so the discharge hole is completely covered with water. Any less and your baits will not last very long. Trial and error says a 3.5 to 4 GPM pump is required to do the job. I ended up with the Shurflo Baitmaster Pro (about $100.) which pumps the correct volume and with enough pressure to offset the weight of the water in the tube.

Create some sort of foot for the tube to rest on and to avoid tipping over. I used two 1 X 3 pieces of teak on opposite sides flush with the bottom of the tube and through bolted. The top of the tube has a line fastened with a clove hitch and each end of the line is fastened to cleats. It is very steady and secure.

Put the baits head down into the tube and they should last for hours. If the tuna are small, you can get 2 or 3 into the tube but they won’t last as long as just one.