Livewells


May/June 2005		Volume 1, Issue 1

Small Boat Livewells

Fishermen in Southern California make heavy use of live baitfish for chum as well as bait. Lively sardines or anchovies are an essential part of exciting our local game fish, and Southern California anglers have done a lot of work perfecting systems for keeping large quantities of these little fish alive and happy. Our live bait is sold in "scoops", roughly a bushel or 10 lbs.

KEY FACTORS IN SELECTING AND INSTALLING LIVE BAIT TANKS:

SIZE:

WATER VOLUME:
Sea water is heavy (roughly 8 lbs / gallon), and in a small boat there will be a balancing act between being able to hold enough bait and performance of the boat. Several sources (see sidebar) recommend the following guidelines for estimating the size livewell required:

First scoop: 25 - 30 gallons
Each additional scoop: 10 gallons

Thus, a 3-scoop livewell would be 25 + 10 + 10 = 45 gallons
Large sportfishing boats may take dozens or scores of scoops of bait, while private boats may take anywhere from 1/2 scoop to 5 - 6 scoops. But keeping in mind the weight of seawater, that 3 scoop tank will weigh roughly 360 lbs. A 6 scoop tank will be roughly 600 lbs.

PHYSICAL SIZE:
For small boats another factor is floor space. Many small boats use a leaning post/seat setup to conserve space.

PLUMBING:

	PUMP CAPACITY: These tanks require circulating water, so they must be fitted with an appropriately-sized pump. The general guideline for sizing the pump: typical fill times should be 5 - 10 minutes. Too fast, and the bait kill themselves from exhaustion, too slow, and they don't get enough oxygen. Pumps are typically rated in gallons per hour (GPH). So, for the 3-scoop / 45 gallon example: To fill the tank in 5 minutes you would need: (45 gallons / 5 min) * (60 minutes/hour) = 540 GPH To fill the tank in 10 minutes you would need: (45 gallons / 10 min) * (60 minutes/hour) = 270 GPH These are ACTUAL FLOW RATES. The pump ratings on bait pumps are nominal flow rates, without any backpressure. Depending upon where your tank and pump are located (the higher & further away the tank is from the waterline, the more backpressure that results), the actual flow rate will be reduced. Some people oversize their pumps, and use a valve to reduce flow. What surprised me was how slow the actual current speed is when filling a tank at these rates. It is not a rush of water.
	DESIGN OF INFLOW AND OUTFLOW PORTS: The ideal design should have water flow in over the entire height of the water column, and take water out over the entire water column. Many people try to use trash cans with simple single-hose setups to add and remove water from the tank. Typically, these are not very effective, because they do not siphon water off over the entire water column. Another thing to look for is a way to adjust water height. In a large tank, it can be very difficult to corral the last few baits when the water level is high. The tank should allow you to lower the water level to make it easier to catch the bait, as well as reduce weight when you don't need the extra water.
	THRU-HULL WATER PICKUP: A good thru-hull, with high-speed pickup cover, is generally considered to be the best choice. However, you can also pick up removable units that fit on the transom. A good strainer cover is essential to avoid picking up seaweed. Don't forget - for thru- hulls, a seacock on the inside is required in order to shut off flow through the thru-hull.
	PUMP DESIGN: Some factors to consider: noise level, current draw, ease of repair or cleaning. The two most common types of pumps are centrifugal and diaphragm. Centrifugal pumps typically have higher capacity and lower current draw than diaphragm pumps, and are often submersible, but they are noisier and more susceptible to getting jammed or clogged by debris. Note that there are at least a couple of centrifugal pumps built with removable motor / impeller cartridges, such as the Shurflo Piranha and the Rule Professional series. These are good ideas, but be aware that if they come apart, you will have a large, unplugged hole in the hull. These types of pumps should have a locking tab or set screw to prevent the cartridge from coming out. A high-water alarm in the bilge would also be a good idea.

CONSTRUCTION:

	CORNERS: All corners need to be rounded. The bait will "nose in" to square corners, and kill themselves. That said, a rectangular tank is OK, as long as the corners have sufficient radius so that the fish can't trap themselves in the corners.
	TRANSLUCENCY: Believe it or not, there is debate about the value (or danger) of having a translucent tank. The most popular small-boat tanks are translucent polyethylene tanks, which let in a lot of light. However, there is one school of thought which says that too much light is disorienting to the baitfish, causing them to run into the sides of the tank, tire out, and die off more quickly. Some people go so far as to paint their translucent tanks to make them opaque.
	BUILT-IN NIGHT LIGHT: It is generally acknowledged that there is value in having a light in the tank at night. Not so that the fish feel safe - it's to keep them from colliding with the side of the tank and with each other, which can kill them off. Not a lot of light is needed, so another alternative is to use a chemical lightstick. Crack the stick, and toss it in the tank.

WHAT WE DID:

We went with a dealer-installed tank and plumbing:

Offshore Products 45 gallon oval "leaning post" tank - This tank is a tall fiberglass 3 scoop tank, with a gelcoat exterior. Full height water inlet and drain, with a half-height setting on the standpipe.
Shurflo Bait Sentry 500 pump - This is a centrifugal pump with a magnetically driven impeller. This allows the motor to continue to spin even if the impeller is jammed, which saves the motor.

In the next issue, we'll talk more about actual field performance of the tank and the pump.