May 16, 2011
Make these holders for larger baits and keep them alive longer.
If you do much bluewater fishing, you may have already heard of tuna tubes. What you may not realize is that it's no big deal to build them yourself.
Why go to the bother? Because big baits are often the ticket for catching big fish. If one or two livies can be kept as backups while two are being fished, you have bait on hand. If you have to stop and catch more live baits, fishing time is wasted, or you may not get any at all. Once they're safely in the tube, however, you can fish all day or run wide open to another destination without all the baits dying out.
Developed originally in Hawaii, tuna tubes are designed for difficult-to-keep-alive baits such as bonito, skipjacks and mackerel. Comprised of vertical PVC tubes fed by a remote source--usually the washdown or livewell pumps--water enters from the bottom and then exits through a fitting near the top. The bait is placed head-first into the pipe, where it has no choice but to take in a flow of seawater through its mouth and gills. The rounded, funnel-shaped indentation at the bottom accommodates the head nicely.
Since each tube will hold only one bait, you need two and possibly more tubes, as long as there's a suitable water supply. However, before you jaunt to the nearest plumbing store, it's important to consider the boat itself. Not only must it possess a first-rate raw washdown system, it must be geared for non-stop use. If it won't pick up when the boat is on plane, you will need to have a high-speed intake installed. This is a bronze scoop with a thru-hull fitting plumbed to the pump. Don't forget the seacock, too.
An important consideration is how far the water source is from the tube itself. The friction of the water moving through plumbing greatly slows its momentum. On my boat, the livewell is directly ahead of the console, and that's where the sillcock (faucet) is. However, the pump is at the stern in the bilge, so I added a second outlet farther back to be sure the flow is strong enough.
Once you've addressed the location of the tube in relation to the water source, move on to the fabrication. You don't have to be a plumber to put it all together--I'm proof of that--but you will need tools such as a hacksaw, drill, file, screwdriver, crescent wrench, channel locks and pliers.
Plan on spending about $50 for materials--less than a third of what a standard ready made tuna tube costs. It will also require between three and five hours of your time, with an additional day to let adhesives dry.
What size tube you choose depends on the baits you plan to use. For small to medium baits such as bullet bonitos and mackerel, a 4-inch diameter will suffice. Six-inch pipe can be purchased for just over two bucks a foot, but if you want five inches you'll have to special-order it. Since it must be bought in 20-foot lengths, you'll have plenty left for your fishing buddies, who are going to want them, too.
The pipe must be cut long enough not only to hold the bait but also the internal plumbing. This consists of a large funnel, sized to fit perfectly inside the pipe. For my project, I bought 6-inch plastic funnels and cut them down with a hacksaw, doing the final shaping with a disk sander. Had I gone with a smaller funnel, the spout would have been too narrow to connect to the water line.
This connection consists of a 1/2-inch insert elbow to the funnel spout with a short piece (three or four inches) of 1-inch clear plastic tubing. Odds are the tubing will want to slip off the funnel--scuff it up a bit with the file--and fix it in place with at least one 1 1/4-inch or larger stainless clamp. If you are working with the larger tube, use a standard 1/2-inch elbow, not the insert style. In this case, the funnel is glued in first and the connecting pipe added during final assembly.
You will now have the internal assembly finished. Though you can fudge on overall tube length, I chose 19 inches for dual 4-inch tubes, 24 inches for a duo of 4- and 6-inchers.
An inch up from the base, drill a 1-inch hole. The funnel can now be inserted up through the base and the bottom of the insert elbow slid partially through the hole. If you started with the correct fitting, the funnel should be centered in the tube, with half an inch of the elbow protruding through the hole. If you have a hard time keeping the elbow positioned properly, slide a small piece of tubing on the elbow where it will rest inside the tube while you fasten it from the outside--this will help keep it in the middle.
In the larger models, the funnel must be glued in place with the elbow in alignment with the hole. To ensure alignment, leave a piece of 1/2-inch PVC pipe in the elbow while the glue sets. Let it dry a full day. This length can then be removed until final assembly, since the funnel will now be permanently in place. The final result will be much more plumber-like than for smaller versions, since it requires fewer clamps. This also reduces cost.
On smaller versions, another piece of tubing can now be slipped over the protruding end of the elbow and clamped. This will hold the internal assembly firmly in place until it can be glued. When gluing in the funnels, use a silicone/poly adhesive because it adheres to plastic better. Even if it leaks a little, it's no big deal since a continual influx of water is needed. Nonetheless, leaks can be easily caulked after initial testing.
An inch and a quarter from the top, drill another hole, this one 1 1/4 inches to accommodate the overflow. Plumb a discharge pipe through this hole. By using such a large fitting, water will leave the tube at the same rate it enters, so there should be little or no overflow. Just make sure you caulk it well because otherwise it will leak.
If your system can handle two tubes, go for it. In my case, for the twin 4-inch model, I connected a 1/2-inch elbow to one tube and a tee to the other. Between them I placed a 1/2-inch PVC ball valve. This allows flow into either one tube or both. At the end is a standard female fitting, capable of hooking up to a regular fill hose. By adding another valve and placing the feed between them, it becomes possible to select which tube to use--a must if different size tubes are employed.
These are all connected by short lengths of 1/2-inch PVC pipe. Extra pieces of this pipe can now be bolted to the base and top at the back. This will make the unit more rigid and durable, and provide an excellent handle. Make sure that you use stainless hardware. Finish the PVC off with caps to give the project a more complete look.
You can customize the array to fit your boat. For example, if your sillcock is in one direction and the site of your overflow in another, this can easily be incorporated into your specific design.
Making your own tuna tubes may seem like a daunting challenge. However, by understanding the concept, having a means of pumping large amounts of water into your bo
at and an afternoon to spare, you can make a set of your own tubes. It's a very satisfying experience, and increases your odds of catching big gamefish.
Tube Shopping List
Here are the parts you need for a basic 4-inch tuna tube:
Two 19-inch PVC tubes (4-inch diameter), or one 24-inch tube (4-inch diameter) and one 24-inch tube (6-inch diameter)
3 feet PVC pipe (1/2-inch diameter)
2 thru-hull fittings (1 inch)
Two 1/2-inch insert elbows (preferably 3 inches long), or substitute two 1/2-inch elbows; if you do so, have a total of four on hand
Four 1/2-inch caps
1 foot of plastic tubing (1-inch inside diameter)
6 stainless clamps (1 1/4-inch or larger), (4 if design all PVC)
2 plastic funnels (cut to fit)
One or two 1/2-inch PVC ball valves (depending on design)
Small can of PVC glue
Tube of silicone/polyurethane adhesive
4 stainless bolts with washers and nuts
One 1/2-inch threaded adapter to connect to pipe
Extra tubing for overflow (contingent on location in boat)
One 1/2-inch tee