Up The Creek - Without a Paddle
By Peter D. duPre |
Wed, 14 Mar 2007
A spun hub can leave you stranded unless you can perform emergency ‚ Prop-Aid.
If, as they say, necessity is the mother of invention, then the development of a new emergency prop repair tool, called Hank Parker's Prop-Aid , is a textbook example of how good things can come out of bad situations.
It all started when a recreational boater went fishing offshore in the Gulf of Mexico a couple of summers ago. The boat, powered by twin 200 hp outboards was trolling close to an offshore rig when both props became entangled in a rope from the rig, resulting in a pair of spun props. Now a spun prop is a hassle at anytime but isn't generally too difficult to fix. All you have to do is remove the spun prop(s) replace them with new props and you are on you way.
In this case, however, it wasn't that easy. Although the boat owner had a pair of spare props on board, the continual use of the boat in salt water had meant that corrosion and electrolysis had fused the props to their respective shafts, making it impossible to replace the props without making a trip to a machine shop. Luckily, the VHF was in good working order and a call for help was answered by an off duty marine mechanic who had decided to take a rare day out fishing. He motored over, checked out the situation and offered to tow the disabled boat the considerable distance back to the marina.
If you've ever been involved in an offshore tow, you know that they can be time consuming and this one was no different. From the time the disabled boat was harnessed until it was back in the marina was a total of nine hours, which gave the off duty mechanic plenty of time to think. Having spun three props on previous trips he knew that a spun prop happens to just about every boater sooner or later, and a quick prop change is not always possible. What was needed was an emergency repair tool that would allow the spun prop to turn fast enough to get the boat home under its own power, so proper repairs could be made in safely onshore. The mechanic thought on this problem long and hard and by the time the nine hour tow had brought the disabled boat back to the marina, he had an idea. He took a piece of marine-grade aluminum and built a device that fits over the end of the exposed prop shaft and into the through-hub exhaust ports. This allowed a spun prop to operate at reduced engine speed so the boat can get back to the marina.
Once the initial Prop-Aid was manufactured and shown around, the response was tremendous. In fact, when well known fishing expert Hank Parker saw the Prop-Aid he immediately wanted to endorse it with his name and it is now called Hank Parker's Prop-Aid .
What is a hub spun?
A spun prop happens when the rubber or plastic sleeve connecting the prop shaft to the prop hub is torn loose or breaks apart. This inner sleeve is vital on modern props, providing a layer of protection for the gears and shafts inside the lower unit as the engine is dropped into gear, when the prop just clips some underwater debris or when a spinning prop momentarily clears the water. The sleeve acts as sort of a shock absorber between the prop blades and the prop shaft, protecting the lower unit from damage. It takes up some shock from the above mentioned items and it is designed to tear or break away under certain conditions such as when the prop bites hard into a log, rock, or heavy mud, allowing the inner splined bushing, drive shaft, and other critical components in the engine to continue to 'spin' so major damage to critical engine parts is avoided.
When this happens, the only recourse is to remove the damaged prop and replace it with a spare. But the problem is that sometimes a damaged prop isn't easy to remove while out on the water. As in the case of the example outlined at the beginning of this article, electrolysis, corrosion or severe damage to the prop and prop shaft can often make it impossible to remove the prop, meaning that spare prop in the storage hold is useless. And that is assuming a boater has made the time and investment to purchase a spare prop. Even when the prop is easily removable, hanging off the stern or getting in the water with a wrench and a pair of pliers to remove the cotter pin and lock nut isn't always fun, especially in a rough chop. Additionally, it is very easy to loose the thrust washer in the drink as you pull off the prop and if that happens and you don't have a spare, you are dead in the water.
With the Hank Parker's Prop-Aid , however, boaters don't have to hassle with prop removal until they are safely on shore. Installing this emergency repair device is easy. Remove the cotter pin securing the lock nut, remove the lock nut and retainer washer, slide the Prop-Aid onto the hub, and reinstall lock nut and cotter pin. It's that easy, and in only a couple of minutes you can be underway. Don't get the idea you can plane off into the sunset, though. The device is intended as an emergency repair designed to get you back to the marina at reduced speed. To prevent harm to the lower unit should you strike another object you should not exceed 2,500 rpm and you will still need to repair the prop once you get home.
Now it is true that rubber-sleeved props that spin out due to over heating will often become operable once they cool down, and as long as the operator is gentle on the throttle, it is sometimes possible to limp the boat home. But
that still means taking a much longer time to get home than with a Prop-Aid in place!
Flo-Torq type dry-sleeve hubs also have their problems. Sometimes when you spin a hub with a removable element, that element can melt or deform in the hub while hot, and as it cools it sticks to the hub making it difficult or impossible to remove from the hub. Also, on a removable element hub, the prop has to be removed from the shaft to replace the element, something that is often difficult while on the water for the reasons outlined above. The Hank Parker's Prop-Aid will also work on dry-sleeve hubs and all you have to do is remove the cotter pin and locknut securing the prop, insert the Prop-Aid into the thru hub exhaust ports, replace the nut and come home.
So is the Hank Parker's Prop-Aid a substitute for carrying a spare prop and thrust washer? Absolutely not. Hank Parker's Prop-Aid is intended for temporary emergency use only, it is not intended as a permanent repair or as a replacement for damaged prop; it is simply designed to let you to operate the motor at up to 2,500 rpm -- so you can get back to the launch ramp. Best of all, the unit can be used over and over, so you'll never have to be stuck out on the water again. Currently, Hank Parker's Prop-Aid fits factory 3-blade and 4-blade props.
Check out our 3-blade version and 4-blade version. Order online, view the dealer list, or if you have a question visit contact us.
Photo Caps:
(All photos courtesy Hank Parker's Prop-Aid)
1. Turn off engine and raise motor
2. Remove cotter pin from prop nut (if applicable). Remove prop nut and retainer washer from spun prop. Do not remove prop!
3. Place Hank Parker's Prop-Aid over shaft, making sure that it fits into the exhaust ports and fits snuggly over the shaft splines.
4. Replace prop nut. Do not replace prop retainer washer. Install cotter pin.
5. Lower motor and start engine. Proceed to shore. Engine should not exceed 2,500 rpm.
