The engine on a tunnel-hull boat is mounted very high, as the prop is fed water through the tunnel, well above the bottom of the boat. According to Scott Deal, this allows tunnel-hulls to run in extremely shallow water, even when mud and sand are being stirred up by the boat's pressure wave.
Rick Murphy goes on to stress the need for horsepower. "Don't underpower your boat," he declares. "Lots of times you'll have a small hole that's a little deeper than the surrounding flat and you can use it to jump on plane. But you need enough horsepower to get the boat up in half its own length."
Lots of good advice. With a little care there will be plenty of fish and seagrass for everyone, plus you may save yourself the embarrassment of calling your insurance agent to tell him about that new lower unit his company is about to buy you.
Shallow-Water Running Gear
While it's true that tunnel-hull boats are often the hull style of choice for extreme shallow-water operation, conventional vee-hull skiffs can be modified to run shallower by adding a jackplate to the boat. A jackplate is a bracket that bolts onto the transom and enables you to raise and lower the outboard-which bolts onto the plate-vertically.
Both manual and hydraulic jackplates are available, although most
serious flats fishermen opt for the hydraulic version. A jackplate offers two advantages: First, like an engine bracket, it moves the engine several inches aft, where it can be mounted higher, even in the lowest position. Second, it allows you to raise the engine even higher while underway to substantially reduce draft.
By adding a custom lower unit with a low-water pickup in the nose cone, you can raise the engine extremely high without worrying about starving it for cooling water.
Many flats pros run four-bladed props for a superior hole-shot when getting on plane, and to maximize the prop's bite when the engine is jacked up at speed. After some experimentation with engine trim combined with different jackplate engine heights, you can get a vee-hull skiff to run in incredibly shallow water.
Bob's Machine Shop is a leading designer and builder of both jackplates and customized nose cones with low-water pickups. Bob's jackplates raise the engine a minimum of 7 1/2 inches above the normal transom mounting height, and the company makes several different jackplate models that extend anywhere from 3 7/8 to ten inches behind the transom.
Bob's Machine Shop, Inc,. Ruskin, FL; (800) 966-3493; www.bobsmachine.com.