The propeller is the only component of your boat that provides forward thrust. At least this should be the case until poor luck befalls it. But even in the unfortunate event that the propeller whacks out into something that can be described as an inanimate object, it could mean spending money on repairs rather than seeing it as a death sentence.

How Does a Hub Get Spun?

A spun hub is damage to the sleeve holding the prop to the shaft, and may occur due to a collision or as a result of the propeller fouling with another boat’s abandoned dock line. This may cause one of the blades to curl into a sickening angle. If not, it may result in other problems which exist in the propeller hub itself.

As in the case of the propeller being wrapped around in the dock line, the engine would keep turning the shaft while the propeller is locked in place. This would cause the rubber hub to get separated from the metal hub, thus it would begin spinning round the bore at speeds of up to 2000rpm.

What this means is that you will notice a significant decrease in acceleration when aiming to push the vessel at top speed. This happens because the engine’s full power is not converted into forward thrust.

How to Determine if You Hub is Spun

How to Remove the Hub

When such nasty things happen to your propeller system, you don’t need to panic since the solution is in replacing the hub itself. The amount of money that you will pay depends on the size of the propeller. But generally, they can be reconditioned at costs of up to $100. If bent blades are involved, it could cost you more.

But first, how do you ascertain that the propeller hub has been ‘’spun’’? You can find out by removing the propeller in order to examine it. The rubber hub is where signs of deterioration can be found. So look for subtle or dramatic signs of malfunction. You’re likely to find out that the hub is twisted or somehow melted.

Alternatively, you could use a center punch and a ball peen hammer to diagnose the problem. You should first remove the propeller and pein a dot onto the metal hub which is adjacent to the mating surface on the propeller. Install the propeller again and go for a test ride. To test it properly, put a load into the vessel as opposed to idling on the dockside. You want a scenario where the hub will be challenged to its maximum capacity. Now, after this test, remove the propeller and look at the dots to see whether or not they are lined up. If they are no longer lining up, then it means that the hub is spinning on its bore.

Replacing the Hub

You should not attempt to do it on your own since you will not succeed. So get out your credit or debt card and head straight to the propeller shops near you. These guys apply lots of pressure when compressing the damaged hub, and they use hydraulic ram for this purpose. The hub in question is then sent into a stainless steel or aluminum recycling bin before a new hub can be formed out of the pressed material.

If you have followed these steps carefully, you should be on your way to enjoying a glorious boat ride once again. But always remember that you should never press the hub onto a propeller when the prop is seated on the blade tips or diffuser ring. This is because certain parts of the propeller can break due to the brittle nature of the casting flaws or metal.

Featured Image – Bell Haven Marina Propeller by Mt.TinDC via Flickr/CC BY-ND 2.0

Categories: Boat Props

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