Boat AccessoriesBoat MaintenanceFishingHow to Fish

Below the Waterline

Over the years I’ve seen some absolutely amazing bait tank installations. On the plus side there have been custom tank projects done by extraordinary craftsmen using the finest materials and shooting for perfection with cost as no object. To the opposite end of the spectrum there have been homemade wonders created from just about every container imaginable with a hodge-podge of plumbing that is often marginal and sometimes downright dangerous to the watertight integrity of the hull. Although the vast majority of installations fall somewhere in between the two extremes, I prefer the former over the other scenario.

A properly installed bait system will function flawlessly for many seasons with minimal grief.

But…the operative word here is “properly”. That means the inlet thru hull in the sweet spot of your particular hull. It means no low spots in the hose run up to the tank. It means the right size wire to supply the pump and a whole school of other stuff that combine to create trouble-free operation and healthy bait. And as we transition to this anchovy pattern it all becomes far more relevant as ‘chovies are weaker bait than the heartier sardines we’ve become accustomed to. So let’s take a closer look at some of these critical components.

I’m always surprised at the amount of issues I find on otherwise worthy boats. I get the fact that sometimes the guys doing the installations aren’t experts in the art and science of West Coast style bait tank installations. But to find high speed pick-ups installed backwards makes me wonder. So if your stock bait well/tank works fills fine when you’re sitting still but loses water when underway that’s one of the first places to look for the problem. Another is the likelihood of the pickup being installed either too far outboard to be in the water at higher speeds or behind a lifting strake or another thru-hull that impede the water flow.

A high speed pickup pointing forward, inboard of the lifting strake and just out from the keel…perfect!!!

I recently met with a potential customer for a custom tank job on a 38′ sport fisher. The boat had just been hauled for a survey and two thru-hulls were installed by a local ship yard in preparation for this job. Sadly, even though there was plenty of room in the engine room compartment, the chosen spot was all the way aft and almost all the way outboard. It was an easy place to work but they couldn’t have selected a worst location on a shallow draft hull. I recommended the boat be re-hauled and the issue remedied but they didn’t want my advice or the additional expense and opted to use it as it was and deal with the inevitable airlock issues. I’m glad they never called back as one of the most critical aspects of an installation is the location of the intake thru-hulls and to be handicapped from the beginning is an exercise in frustration.

The best location for the intakes has to be figured out on each boat.

Typically aboard inboard vessels the sweet spot is somewhere in the engine compartment and on the inboard or keel side of the outboard engine stringers. This location keeps the inlets away from most of the air bubbles and is well below the waterline to minimize airlock issues with centrifugal pumps. On inboard/outboard boats most of the time the mid-ships locations are not accessible so the next best spot is just ahead of the engine, in between the stringers. Outboard boats typically present the most difficult installation issues as many manufacturers offer limited access to the bilge area under the motor well. But there’s always a way even if radical surgery is required to open up the space. For trouble-free operation, try to make sure your thru-hull has an unobstructed, clear view of the water ahead of it.

Once the actual thru-hull is installed the next step is the ball valve. Don’t go hardware store junk; be sure to use a good marine-grade gear. The cheap stuff corrodes, freezes up and fails when you need it fast. Another benefit to marine-grade parts is they are what is called “full-port”. The hole in the ball is as big as possible and doesn’t restrict the flow to the pump. The ball valve is typically mounted straight up on the valve but if space is critical it can be mounted horizontally. If necessary, screw on an elbow to lay the pump horizontally, and have the valve pointed forward if to minimize airlocks. Buck-Algonquin and Groco are the major brands we use.

A 22′ boat with a nice, clean and well maintained bilge area.

Those are also the companies that make the straight and 90 degree pipe to hose fittings we use. I never use ½” pipe, it’s too small to pass enough water. Most of our plumbing is done with 3/4” and 1” pipe thread fittings and 3/4” and 1” hose size On bigger tanks with higher volume pumps we step it up to 1 1/2” hose. For below the waterline usage we almost always opt for the security of brass/bronze fittings. On our control manifolds that are above the waterline we mostly use schedule 80 PVC fittings and valves. Some caution in assembly is order with PVC. I use 4 wraps of Teflon tape and then hand-tighten until snug. Then mark the fitting with a black Sharpie and use a strap wrench to go two more full turns and you’re done. My strap wrench was less than 10 bucks at Home Depot and works far better than some fancy ones I’ve had.

On many of our trailer boat installations we screw one of the smaller Rule or Bait sentry pumps straight into the ball valve. This is not my favorite way to proceed but if space or budget considerations preclude the use of a sea strainer then oh well. If the water you fish is relatively clean you’ll be ok. But…be prepared for issues. Eel grass is the main culprit and it can be a nightmare for the unprepared. Note the wad of grass wound up in the impellor of a high quality pump. The owner had opted out of a strainer during the original installation but he saw the light after losing a tank of bait overnight.

Guess why the flow was slow???

In a perfect world there is an easily accessible location for the thru-hull/valve combo and then a nearby bulkhead to mount the pump(s) and strainer(s) that keeps them well below the waterline. I use brass/bronze fittings below the waterline and always connect the pump and strainer to the boats bonding system if it has one. On many of our 60-90 gallon tanks we use the Jabsco Cyclone pump. It is a greatly upgraded Centri-Puppy, other than the fact they did away with the small port we used to attach a small hose to vent off airlock issues. Fortunately the internal design is far more efficient than the older styles.

Just today I looked at a customer’s boat to plan his installation. The boat is an inboard/outboard and there is very little space to work with barely 6” between the pulleys on the front of the motor and the forward bulkhead. The boat was outfitted with a small, nylon thru-hull insufficient for our needs. It is wedged deep in the bottom of the bilge and very difficult to access. To change it out is going to be tough as is the mounting of the strainer/pump combo. Other wires and hoses have to be moved and an existing macerator has to be relocated. Collectively it will be quite a project to get the bait tank plumbing right. But when complete he’ll be able to have total confidence in the new components.

The use of cheap hose can potentially be deadly.

As far as performance goes, the non-spiraled hose has a tendency to kink and reduce the flow to the tank. With less ability to maintain its shape in sharper bends, the kinks often develop after the job is all buttoned up and considered done. When we get the calls about reduced fill times, one of the first recommendations is to check the whole run for those performance-robbing kinks. The use of hose not rated for below-the-waterline applications brings another bigger risk…sinking the boat. With age, non-reinforced can crack and split, potentially introducing a large volume of water to the bilge area. Next to a fire, the sight of a full bilge is one of the scarier moments you’ll ever have at sea.

We’ve had excellent success with Trident Livewell Hose (#147). It is clear with a black spiral; it’s stiff and is a bit difficult to work with. To get it on most plumbing fittings use a gentle and controlled application of heat from a heat gun. It takes a few minutes to evenly heat the end of the hose until it is slightly softened and will easily slide on a lubed up fitting. I once watched some guys at a dealership use a cigarette lighter to try to soften the hose…I do not recommend that approach. Snug up the properly sized clamps while the hose is still warm and you’ll get a perfect seal every time. Double clamp all connections if the fitting provides enough length to accommodate both clamps.

Pump/strainer combo ready for fittings and the final hookup.

We also use the black, multi-ply, wire reinforced hose when conditions dictate. The dual wire variety has a tight bend radius, is very abrasion resistant and unfortunately is quite expensive. But it is the way to go when you need the best. Regardless of the type of hose used, make sure the run is uphill all the way from the thru-hull to the pump/strainer combo then to the manifold (if there is one) and up to the tank. Any dips or low spots can trap an air bubble and cause airlocks and consequent misery.

A state-of-the-art bait pump installation aboard the 34′ Radovcich “Black Beard”.

The above installation tips apply to most of what we fish here on the West Coast. Small inflatables, aluminum skiffs and cat hulls all have their unique characteristics and often require additional techniques. The most challenging of all are the ultra-high-speed, stepped hull 900-1200 horsepower new breed of East Coast style tournament boats. They require a different mindset and a far more sophisticated parts list. But we’ll save those discussions for Part Two.

Capt. Mark Wisch
Well-known California captain, writer, speaker and tackle shop owner, Capt. Mark Wisch has been helping anglers catch fish along the West Coast for de...