Can A Bent Prop Be Repaired

Sooner or later it happens to all of us, fifty-fifty the most careful of navigators – the prop gets dinged. Sometimes it's a little more than a ding, notwithstanding all of the blades are yet at that place, more or less. Your boat dealer, local mechanic, and the local boatyard will all tell you the same thing -- replace the prop! (They can't fix information technology and want to sell y'all a new screw.) But you lot wonder: "Can't a good prop shop salvage this with some artistic metalworking and make information technology almost as good as new?" If you've faced that dilemma, yous are non alone.

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Tin can this prop be repaired?

First of all, was your prop doing a proficient task before it was damaged? That means—

1. Was your prop keeping your motor in the proper rpm range? Failure to do this results in poor fuel economy, poor performance, and most expensive of all—potentially catastrophic harm to your motor.

2. Did your boat accelerate and corner well?

3. Did y'all experience noticeable vibration from the prop? Zippo skillful comes from vibration!

If there are issues with whatsoever of these items, it might be fourth dimension to consult with a prop manufacturer or your propeller dealer and supplant your prop. After all, a prop that is perfectly repaired, but is not properly suited for your application—is perfectly improper.

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Can this prop be repaired? Should it be?

Aluminum Props

If the basic functioning factors were okay, next you demand to evaluate the feasibility of repairing the prop. If you have an aluminum prop, yous should audit for excessive metal loss (more than than ten% of the blade expanse), extended cracks, blades that are too thin, or cavitation burns. If your prop has any of these issues, bite the bullet.

An boosted consideration is whether your prop may need the inner hub that protects your drive railroad train replaced. This tin add another $40-60 to the repair toll, so it needs to be examined every bit well. Aluminum propellers are adequately cheap to purchase new, so y'all don't desire to put too much money into them, unless they are in good overall condition.

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The left image shows the results of a collision with a heavy chain. Equally you can run across the bronze blades are badly bent and damaged. The correct manus paradigm shows the finished upshot. (Pictures courtesy of French Marine Motors, United kingdom of great britain and northern ireland.)

Statuary Wheels

What if you have a V-drive or inboard skiboat/cruiser with bronze wheels? The critical issue here is blade thickness. Even if you fabricated a "pretzel" out of your prop, skilled prop shops can piece of work wonders. But, if the blades are excessively thin, you may exist sinking money into a lost cause. When you lot straighten, you need to regrind to shine the surface and remove dents and nicks. Each time this is done, critical metallic thickness is lost. Remember that a 20% reduction in thickness may reduce the forcefulness by up to 50%.

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Cavitation has worked its magic on this stainless steel prop.

Stainless props demand to exist evaluated on similar criteria as bronze ones. First of all, is the remaining thickness okay? Any signs of cracks? How extensive is the damage? How much metal is missing?

By and large speaking, stainless props are made from 2 general types of metals. High -carbon stainless is very strong and harm resistant. It welds well and can generally be repaired unless information technology is bent excessively. Given its loftier strength, it does not like beingness bent into a pretzel and straightened.

High Strength or Depression Strength?

Another characteristic of loftier-force stainless is the fact that information technology shows more corrosion than depression-strength stainless. This is a natural consequence of the higher carbon steel content used in the alloy. Low-forcefulness stainless uses more nickel in the alloying combination. This provides a meaning increase in corrosion resistance, only also drops the tensile strength, typically by 50% compared to the high-forcefulness fabric.

The cloth used in low-strength stainless props is more similar to that used for deck hardware. Since the forcefulness of the textile is more like bronze than a high strength stainless, it will "pretzel" pretty easily. The practiced news is that it can normally exist straightened out again.

In either case, the effect will exist to examine for plenty bract thickness to allow the repair to be completed and still take sufficient "meat" left for immovability.

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Proper propeller repair takes time and the right equipment.

Repairing Props Is an Fine art

If the decision is to repair the prop, expect for a well-recommended repair shop. The proper repair of propellers is an art. It takes a true skilled technician to do the job you desire. There are many practiced repair facilities bachelor. If you have a prop shop that is doing a nifty chore for you, stay with them. Nevertheless, if you are looking for a shop, you may want to consult the National Marine Propeller Association (http://www.nmpa.cyberspace), which provides grooming and workshops to help members go on their technical skills electric current. It may be a good resource to assist yous in finding a skilled prop shop.