Are you using the same boat propeller for a long time and worried about the prop condition? Is it OK to use a boat propeller for extended periods without replacing it? How often to replace a boat propeller?
A boat propeller needs to be replaced if any of the blade edges or all are broken or chipped by more than 10%-15%. However, the propeller’s condition would tell how long you can use it, so unless you hit something that resulted in dents or dings on the propeller no need to replace a boat propeller.
Time and water do not damage a boat propeller; rocks and other objects do. The condition of the propeller would tell how long you can use it. If you haven’t hit too many objects and it’s not dinged and has had no significant dents or nicks, you can use it for many more months or years.
You need not worry about the propeller replacement if you haven’t hit anything or there or no nicks/dents on it. So, a boat propeller can last forever or longer than you will unless you hit something. “Time and water will not damage the boat propeller.”
If you hit a rock the day you bought it, you need to replace it if the damage is significant. So, whenever you hit something with the propeller, check the resulted damage and replace or recondition it. Propeller is like wheels for a boat. Unless you skid the car often or hit the propeller often, they both last for a long time.
Unquestionably, there will be many people out there who haven’t changed (replaced) their boat propeller in their last decade or more. The “MAINTENANCE” is crucial here. A propeller is not like a bottom paint or any to wear out in time. It will last long enough until you hit something.
When to replace a boat propeller? 4 bad propeller symptoms
We will now see the symptoms that a bad or damaged boat propeller will show. However, it would be best if you verify those bad symptoms before replacing the propeller.
Visual confirmation: Bad visual signs
More than anything else, bad visuals tell you more, and you can decide on that factor most times. You can decide that by just looking at the propeller, if any of the blade edges or all are broken or chipped by more than 10%-15%, it’s recommended to replace the propeller.
Otherwise, you can take it to the repair shop and recondition it back. You can use it forever if there are no nicks or dings or not chipped at all. Even the corrosion can be a problem on your propeller; if the corrosion ate the propeller, you need to replace or repair it.
So, by looking at the propeller, you can decide whether to replace it or not. However, there will be many situations where you can’t decide by just looking at it. Below there are three elements to check; if it passes those tests, you don’t need to replace it.
Increase in fuel consumption: A small nick can increase 20% fuel burn or more
A damaged or bad boat propeller can drastically increase your fuel economy (consumption). You might be thinking that the outboard has a problem or become old, but it may not be the actual reason. As shown in the above image, that small nick on the propeller can increase fuel consumption by 10% or more.
If the propeller has big or noticeable damage on it, it can cause a lot of fuel waste, requiring you to spend more money than usual when refilling your tank. It also affects how long you can stay in the waters. So, if you notice any fuel economy changes lately, it might be the propeller that is consuming more.
The best way to inspect it is by using another prop and comparing the results. You can take a prop from your friend or any and inspect the fuel consumption of the two props. If both the values are not close to each other, your prop needs some repair or replacement.
Increase in bumpiness during rides
A bad propeller will make your ride bumpy. However, if the damage is small, you may not notice it, but that doesn’t mean it isn’t a problem. If your boat isn’t running smoothly, your propeller’s blades may have sustained some warping or denting.
That increased vibration (bumpiness) is due to the water that is not sliding over the dinged or damaged propeller smoothly, which will put unwanted and potentially damaging stress on your shaft, lower unit, and trim tab hardware. There won’t be any disturbances if the water slides over the propeller smoothly.
The best way to inspect it is by using another prop and comparing the bumpiness. But if the prop is damaged and going in rough waters, you can’t determine it yourself. So, take a ride in calm waters and decide it yourself.
Speed reduction: A small ding on one blade can affect (lower) the RPMs
A damaged or bad propeller will reduce the max RPMs due to the water that is not sliding on the dinged propeller smoothly, directly decreasing the speed. However, if the damage is very little, you may not notice the speed reduction, but severe damages are very noticeable.
The other signs are your boat may take a long time to reach top speeds (cruise speed). It also struggles to get on plane. If you see all these problems lately, your propeller might be causing all those problems. So, check the propeller often to find those problems early.
If you leave the issue too long, it may damage the engine’s inner workings, including the pistons, bearings, and crankshaft. Most facilities that do repair work can adjust the pitch, saving you from boat propeller replacement costs. So, repair or replace it quickly.
How to get the most out of your boat propeller?
As always, maintenance plays a crucial role in getting most of your propeller along with the type, aluminum or stainless steel. Depending on the type of propeller you have, you may be able to increase your boat’s speed a little. But the rest are the same.
If speed is your thing, go for stainless steel props. Stainless steel props are lighter and thinner than aluminum props. Unlike stainless steel props, aluminum propellers tend to flex at very high speeds. Stainless steel props will cut through the water more effectively and don’t flex at increased speed.
Inspect the propeller and propeller shaft frequently. It’s a good practice to inspect the prop after every ride, it may be a bit too much, but it’s a good practice. Remove the propeller and thrust washer, and look for any fishing wire or any that is surrounding themselves to the shaft. If no fishing line, all good and put it back.
Apply grease on the propeller shaft every 150 or 200 hours. Depending on the usage, apply some grease on the propeller shaft every 150 hours or 200 hours to lubricate them well. Spread the grease across the shaft and then reinstall the propeller back on.
Look for small dents or dings on the propeller frequently. While inspecting the propeller, check for all the dents and dings; if the propeller is dinged or has dents, fix them in the early stages so that they won’t become big.
Do regular maintenance and be careful in shallow waters; your propeller will last for a long time. If you leave the issue too long, it may damage the engine’s inner workings, including the pistons, bearings, and crankshaft. Most facilities that do repair work can adjust the pitch, saving you from boat propeller replacement costs.
Check this small and helpful video on removing the boat propeller and how to inspect for fishing lines on the shaft.
Bottom line
The condition of the prop would tell how long you can use it. Time and water do not damage a boat propeller; rocks and other objects do. If all the blade edges or all are broken or chipped by more than 10%-15%, it’s recommended to replace or recondition the boat propeller.
You need not worry about the propeller replacement or repair if you haven’t hit anything or there are no nicks/dents on it. Definitely, you can use it forever if it is not damaged. So, a boat propeller can last forever or longer than you will unless you hit something.
Running with a bad or damaged propeller will result in lower top speed, worse fuel economy, and increased vibration, which will put unwanted and potentially damaging stress on your shaft, lower unit, and trim tabs hardware. So, recondition it or replace the propeller based on the damages quickly.
Even a small ding on one blade of the prop will affect RPMs and may cause enough problems to “work” your drive train a lot harder than you ever intended to. Severe prop damage is very noticeable; if the damage is small, you won’t notice it – but that doesn’t mean it isn’t a problem. Good luck.
