Maybe you want to be the first fisherman to hit the hotspot, leave a slip neighbor in your wake, or maybe you're just impatient. Whatever the reason, just about everyone wishes their boat went a little bit faster.
The good news is, it can – if you try these speed-boosting tricks.
LENNY RUDOWYou want to go 5 MPH faster? No problem!Start with a look at your prop. Running with the wrong prop is probably where the largest number of boaters give up speed, particularly those running outboard and stern-drive boats. If you're running with an aluminum prop, you can gain two or three MPH immediately just by swapping it out for one made of stainless steel. Stainless props don't flex as much as those made of aluminum when under load, and the end result is a faster boat.
Next, consider your prop's pitch. In most cases, the prop that came with the motor when you bought it was designed to spin within the manufacturer's recommended maximum RPM range. However, this is often determined on a lightly-loaded boat. In real-world use, virtually every boat on the water will be running heavier than when it was new.
While some dealers take this into account when propping the boat, many do not. How can you tell if your prop is correctly pitched? Run the boat at wide-open throttle on flat water. Trim the motor up until you first hear the howl of the prop sucking air, then take the trim back down a notch so the prop has a good bite in the water again. Record your wide-open throttle RPM, and then match it up with the recommended maximum RPM in the engine manufacturer's instruction manual. (You lost that years ago? No problem–most of them are posted on the web these days.)
If your engine isn't near the high end of the manufacturer's recommendation, try swapping props for one that has less pitch. Usually, a two-inch drop in pitch will gain you about 300 RPM at wide-open throttle. So if you're spinning 4,200 RPM at wide-open and your engine is rated to turn between 5,000 and 5,500 (as many modern outboards are,) try dropping pitch a couple of notches.
The number of blades your prop has will also affect speed. Four blade props will get you a quicker hole-shot and reduce vibrations, but that extra blade adds drag. In most cases, switching from a four-bladed prop to a three-blader will gain you between one and three MPH at the top-end. Is it worth the sacrifice to trade it out? That's a judgment call only you can make.
LENNY RUDOWA jack plate will set the motor back from the transom; high-quality units allow the captain to raise or lower the motor from the helm.One caveat: If you're running a single-engine powercat or a boat with a tunnel in the hull, going to a three bladed prop may allow ventilation. Many boats of this type need all four blades to overcome the turbulence caused by the tunnel, and three bladed props should be avoided because they'll allow the engine to over-rev when the ventilation occurs.
WEIGHTY DECISIONS
The amount of friction between your hull and the water depends greatly upon one simple factor: how much wetted surface your boat has when on plane. In other words, how much boat is touching the water.
This goes for any type of boat, from a 1,000-HP Cigarette to a sailboard. And the amount of wetted surface your boat has depends on how much it weighs. The heavier it is, the deeper it will sink into the water. Load up your fishing gear, water skis, picnic supplies, coolers, and spare clothes, then pull your boat and trailer onto a truck scale. It's a fair bet you find that the boat's weight has increased by 10 to 15 percent over what's stated in the manufacturer's catalog.
And, by the way, many of those manufacturer's specs are given with a "dry" boat. Fuel tanks and water tanks are bone-dry. But water adds about eight pounds per gallon to your boat's weight, and gasoline adds around six. (Hint: if you don't use your onboard water, empty those tanks and stop hauling around all that unused weight!) If you're running a 20-foot to 24-foot boat that weighs between 2,000 pounds and 3,000 pounds, generally speaking you can expect to lose one MPH of speed for every 250 pounds of weight you add. So ask yourself: is it time to put your boat on a diet?
First, get rid of excess tackle and unnecessary gear. If you haven't used an item in the last three trips, remove it from the boat. Things like special-purpose anchors, cast nets and boxes of heavy trolling weights can be stowed in a shed or garage, and only carried when you foresee using them. Now look for heavy gear that you decide must stay onboard. Where do you have it stowed? Is there a spare prop or a tool box under the foredeck? Remember that placing weight forward tends to increase wetted surface when on plane. Unless your boat has a problem getting on plane and you need that gear up forward to weight the bow down, moving it all into an aft or amidships compartment will help.
