Boat propellers are subject to damage for a multitude of reasons. However, running a vessel on a bent or broken prop can lead to more serious internal damage. For this reason, it is imperative to have a propeller replaced or repaired in the event it is no longer pitched correctly. I’ll admit I have bent props, and it is not an enjoyable experience. If you have a bent propeller, you need to know the implications of continuing to operate with damage.
Most Common Causes Of Propeller Damage
Without question, there are a multitude of reasons why boat props become damaged. In some cases, it is unavoidable, while in others, it is simply failing to use common sense. Here are the most common reasons why propellers become damaged.
Likely, the most prominent cause of damage to propellers on boats is running aground. I have run aground a couple of times and, as a result, dinged my propeller to the point that it needed to be repaired.
For the most part, running aground can be prevented when closely monitoring charts and electronic navigation equipment.
In a situation where you need to run the engine in shallow depths, it is imperative to trim up the motor.
Failing To Raise The Engine At The Boat Ramp
One of the most nerve racking sights to see is a boat owner hauling a boat out of the water with the motor trimmed down.
Unfortunately, not only is prop damage likely, but the skeg will take the brunt of the blow. The skeg and propeller are at risk of chipping or breaking. The combination of repairing the two will not be friendly to the wallet.
Striking Floating Objects
Our lakes, rivers, oceans, and inland waters are littered with floating objects. Importantly, many of the objects are barely visible. For this reason, it is not uncommon for the propeller to strike submerged objects and cause damage.
I have run vessels in the open ocean and feathered the wheels on a twin screw Cabo Express. Unfortunately, the wheels were bent to the point that they required a haulout and immediate repair.
Interestingly, I never saw the object. Instead, I heard the impact and dove into the water to inspect.
Internal Damage As A Result Of Running On A Bent Propeller
Unfortunately, a multitude of implications arise when running the boat’s motor with a bent prop. It is important to understand the harm caused by running with damaged propellers.
Poor Gas Mileage
Without a doubt, you will be spending more money driving with a bent or dinged propeller. A propeller’s pitch is calculated to maximize performance and minimize fuel burn.
As you can imagine, a chip or bend in a propeller blade or blades throws off the pitch. You can expect to burn up to 10 percent more fuel when operating with an improperly pitched prop.
Considering the cost of fuel from a marina, it is wise to have the prop repaired rather than continue to operate it.
Lack Of Performance
Similar to poor gas mileage is decreased performance. Ultimately, the two go hand in hand. When the pitch of the propeller has been disrupted, the water does not flow properly through the blades.
As an operator, you are likely to notice increased vibration and decreased performance. The boat will be sluggish to get up on plane, fail to reach top speed and maneuver more laboriously.
I have noticed vibration aboard vessels with bent props or wheels. Remember, the propeller can be repaired or replaced.
Bearing And Shaft Damage
Ultimately, the worst risk associated with running on a bent prop is bearing and shaft damage. Not only will you be required to repair the proper but potentially replace the lower unit on an outboard or shaft and bearings on an inboard engine.
Shaft and bearings are at risk of failure due to strain. The strain is a result of an improperly pitched prop, which then causes severe vibration, leading to internal damage.
Without a doubt, to avoid spending money unnecessarily, I recommend bringing the boat into the shop immediately, especially when the vibration is significant.
Don’t Operate With A Bent Propeller
Bent props can happen to anyone, especially when you least expect it. I didn’t think I would strike a partially submerged object on a bright and clear sunny day. Importantly, nobody is immune to prop damage. It simply happens from time to time. However, the most important issue is fixing the problem before it escalates.