How to Handle Small Powerboats Safely
Hints on Boat Performance, Turning, Stability, Stopping and Backing
Nov 22, 2008
There is no doubt, boats handle differently than a car. They turn differently, can move abruptly as loads shift, they have no brakes, and backup poorly. Much of the difference is a result of their moving through a shifting, low friction liquid: water. Here are a few hints on how to handle a small powerboat.
A Simple Power Boat
As a starting point, techniques described here are appropriate for a small powerboat. The prototype vessel for this discussion has a deep-vee shaped, planing mono-hull, ranging from 14 to 28 feet in length, and is powered by a single outboard motor. Vessels equipped with stern drives, straight shafts, twin screws, rudders, multiple hulls, or displacement hulls will handle much differently. One of the best ways to learn boat handling is to ride along with a more experienced boater.
Steering a Boat is Different than Driving a Car
Cars pivot around a point centered between the front tires such that the body of the vehicle follows the front axle through a turn. The pivot point on a boat lies about a third of its length back from the bow, when the vessel is moving forward. To make a turn, the rear (stern) of the boat needs to be shifted in the direction of the turn by the outboard engine, which points to bow into the desired direction of travel.
This means that there is a delay in starting a turn, since most of the boat must in aligned in the desired direction of travel before the turn can be completed. Another important consideration is that the boat needs to be moving through the water for a turn to occur. Many new boaters don't use enough power to complete a turn and are surprised of the results going too slow in the most inopportune moments. A small burst of throttle can quickly push a boat through a turn.
Small Boat Instability
Performance and handling of small boats is critically affected by vessel stability. There are a number of factors and actions that change the stability of a boat:
- Applying additional throttle will increase speed, resulting in a tighter turning radius and lower stability
- Sudden or abrupt maneuvers, especially in turns can upset and capsize a planing hull boat
- The sudden shift of cargo or passengers can adversely effect vessel handling
- Balancing boat loads is critical to handling and performance. As an example, too much weight in the bow can make a boat plow through the water.
Stopping a Boat
The key consideration here is that there are no brakes. A planing boat takes some time to stop after the throttle is released. It is vital for a boat operator to be thinking ahead of the boat. Practice stopping at different speeds to get a feel for the time and distance required to come to a stop. At slower speeds, reversing the propeller can help a little in a pinch.
One additional safety consideration for boats with low transoms, a quick stop can swamp a boat as the wake overtakes it.
Backing Up a Boat
The pivot point on a boat shifts to the rear when backing. Boats will try to follow the pull of the propeller moving through the water. The centerline of the keel will try to keep the boat moving in a straight line. Most outboard equipped boats have a flat transom and may have a well built into the transom for the engine. A flat transom pushes up a wall of water as it is forced back. Moving too fast astern can swamp a small boat.
It is difficult to back a single engine boat. The descending blade of a propeller generates more thrust as it moves through the water. This will make a single engined boat pull in one direction or the other as it backs up. Once a boat operator becomes familiar with this tendency, it can actually be used to advantage in mooring a boat.
These are only a few tips for handling a boat. The best way to become a better boater is to go out often and boat with more experienced people. This is certainly one benefit found in joining the Coast Guard Auxiliary.
