boatingonthehudson.com28 September 2012

845-359-5522695 Piermont Ave., Piermont, NY

www.tappanzeemarina.com20 Ton OPEN ENDTRAVELIFT

M a r i n a

Tappan Zee

NEW to TZM - SPECIAL PRICING & LIGHTHOUSE DINNER COUPONS

Lowest Labor Rates in VicinityPiermont’s Deepest Draft Marina

New Customer

INCENTIVE CALL FOR DETAILS

STORAGEReserve Now for Best Value

METROSODA BLASTING

Before

After

“Strip your boat... not your bank account”

118 Avenue F, Lodi, NJ 07644ed@metrosodablasting.com201-233-0389

Marine Paint RemovalMobile Service

29boatingonthehudson.com September 2012

Precision Propeller and its staff, loves the propeller business. With over 25years in the business, our entire staff gets involved in not only repairing propellers but is concerned the actual installation of the propeller is done in the proper manner. Why? Because the propeller is only one segment of your boats ability to perform properly!

Not only do you require the proper pro-peller and installation, it is only one com-ponent of an integrated power system that includes the, shaft, strut, coupling, bearing, transmission and engine. It is all designed to work together under a wide variety of loads and conditions.

What is fascinating about this business is the many misunderstandings that occur with boat owners when they try to understand how to match all these com-

by Gabe CapobianchiGabe Capobianchi is Co-Owner of Precision Propeller.

ponents without getting expert advice. Precision Props years of experience, is available to all and can help you have an enjoyable summer of boat performance. It is part of our service to you when you ask us to “repair or replace your pro-peller.” The following series of pho-

tographs shows the proper way of installing a propeller on a straight shaft inboard. In this example the customer was changing propellers from a three blade to four-blade propeller to test improved perfor-mance characteristics on a thirty-two foot boat.

Here is the shaft. It’s a 1 ½-tapered shaft. The most important thing to keep in mind is that it is a machined tapered shaft going on to a machined tapered propeller. These are two machined parts that must create a minimum of 75% contact between the 2 of them. There can never be any type of, never seize, or lubricant place on the shaft. By applying a lubricant to the shaft you actually create a barrier between the two-machined parts; the shaft taper and the propeller taper. The 2 machined contacts of the shaft taper and the propeller taper is what makes the propeller spin under the torque of the shaft. Many people think it’s the key on that shaft, but that is not true. (I will get to the importance of the key later on in the article.) If there was any part of a boat that you would NEVER want to come off especially as your motoring along at 40 knots, it’s the propeller. The best-installed pro-pellers are the ones that are the most difficult to take off.

Step 1 - Bare shaft.

PROPERLY INSTALLING PROPELLERS on STRAIGHT SHAFT BOATS

boatingonthehudson.com30 September 2012

Step 2:

I put the propeller on WITHOUT the key and firmly ran it up the taper. Once I did that I made a line on the shaft against the propeller hub. This will act as a reference point later on.

Step 3

The key:

I then removed the pro-peller and installed the key, into the keyway. As mentioned before, the key does not actually turn the propeller on the shaft, but acts as the breaking point, or impact point should you hit something with your propeller. Think of it as a shear pin.

I made a line on the shaft against the propeller hub. This will act as a reference point later on.

No Key

Precision Propeller is proud and pleased to help you get the most out of your boat. Call us at 845 562 2880.

We service over 150 marinas in the Tri-State Area…weekly.

You can email us at gabe@precision-props.com or go to our website at

www.precision-props.com

31boatingonthehudson.com September 2012

Step 4INSTALLING THE PROPI took the propeller and carefully ran it up the shaft making

sure not to push the key along with it. When I did that, I could see that I lined up exactly where I made the mark WITHOUT the key installed. I now knew the prop was on correctly. If I did not line up with my previous mark, something was wrong. Typically if you don’t reach that mark, the key would be jammed in the key way slot preventing it to get all the way up the taper. This is referred to a “key jammed”, and is the number one cause of shaft failure.

. DO NOT USE NEVER SIEZE OR GREASE ON THE PROP SHAFT WHEN INSTALLING A PROPLLER

Step 5THE NUTSHere is where it gets interesting. What I did

next was took the large nut and run it all the way against the propeller.

Step 6Then I tightened the LARGE nut against the

propeller. After the LARGE nut was tight, I REMOVED the large nut and ran the THIN nut against the propeller.

Step 7Once the thin nut was tightened I ran the

large nut on jamming the 2 together. Hence why they are called jam nuts. Think about how a bolt, nut and washer as assembled. You have the bolt (shaft) then you put a washer on first (thin nut) and then the nut (large nut). The thin nut acts as a lock washer in this case.

Step 8And finally the cotter pin. Theoretically the

cotter pin is there in case the nuts come loose, but structurally if the nuts came loose under power, it would take seconds for the cotter pin to fail causing the nuts and propellers to come off. In my opinion, if the propeller is on correctly, and the nuts are secure, the only use I can see for the cotter pin is the mental “last piece of the puzzle”.

So, the props are on, and the boat is getting ready to go back in the water.

Disclaimer: Precision Propeller provides this information as a service to its customers and cannot be held responsible for the actual installa-tion by “others” for that installation.

Please exercise all precautions in the installation and use of your boat!