Shiny New Wheels - Day 18 - Grand Rivers, KY

Time to find out just how much propeller damage we sustained from the get-home-itis hit on the Illinois River, which occured at 30 MPH and the numerous (6 to 8) hits on the mighty Mississippi that occurred despite our intense vigilance.

Moving the boat into the travel lift

Up she goes

The lifting process started around 11:30 AM and as the boat came out of the water the technician drew my attention to the starboard (right side) spur saying "here's your problem." 

By way of explanation, a spur is a cutter attached to the shaft just forward of the propellers designed to cut lines that would otherwise get fouled in the props.  The photo below shows an intact spur. Click here for an animated view of the installation.

Undamaged spur on port side.  The cutter is mounted on the shaft

The photo below show that the force of the object we struck hit the bracket on the strut, turned it about 30 degrees and sheered off two of the three 3/8th inch mounting bolts.  You will also notice that one section of cutter on the shaft has fractured.

Damaged starboard spur

Then came the big surprise.  There was no visible damage to the props. Apparently, the spur took the hit and deflected the object.  In the photo below, Tom Hilbert of Prop Scan St. Louis, who fortuitously was on site delivering repaired propellers, confirmed that there was no obvious damage.

Tom Hilbert inspecting the port propeller

The only visible damage was a very slight nick that was causing cavitation.  Very hard to see.  Follow the slight discoloration on the left side of the blade outward to where it appears a bit shiny.

A slight nick from long ago.  Not a problem

The closest thing we could find to damage was the fact that when you rotated the prop by a fixed wooden dowel, two of the blades on the starboard prop touched the dowel.  Tom estimated 1/16th of inch and stated that this was within tolerance and not sufficient to cause vibration.

Given the fact that the props had never been scanned since we bought the boat and the fact that we had put over 500 hours on these props, I made the decision to have them scanned to identify any problems. Scanning involves rotating the props by optical sensors that transmit data to a computer to measure the form and pitch of the props.  The data enables the technician to then manually, by hammering, bring the prop to ISO specifications.  A very technical explanation for making it "perfect."  A properly shaped propeller reduces fuel consumption, vibration and, ultimately, blade failure.

Tom and I discussed, at length, the fact that we heard stuff hit the hull (a decided whack) 6 to 8 times and yet there was not visible evidence of damage on the blades.  The best explanation is stuff that hits the prop at 1030 to 1060 RPMs (trawler speed) is defected and hits the hull.  At full cruising speed, 30 MPH, the prop takes the full force before deflecting the object.  Bottom line: Trawler speed, 9.7 MPH, saves both fuel and props.

So, the yard removed the props, which itself is no small task. 

Technicians removing the propeller using a prop puller

Shaft without propeller.  Note the underwater exhaust in the upper right corner

The spare props were quickly installed and the boat was dropped back in the water.  Note: I invested $6,100 in a spare set of props using the theory "that it's better to have them and not need them then to need them and not have them."  Also noteworthy is the fact that it took about 6 weeks to get the props made by Michigan Wheel.  Clear evidence that spare props are a wise investment when you embark on a 6,000 mile trip with lots of potential to damage props.

Tom inspecting the spare props

Mounted shiny new (spare) propeller

Ready to go back in the water

Moments to splash down

While I have not received the bill, I estimate that the total cost to swap out the props and remove the damaged spur will be $660 ($400 to lift the boat and 4 hours of labor at a reasonable $60/hr).  The cost to repair the old props is pending.  It could be zero if the props scan to ISO specifications.

Speaking of shiny, it was time to wash the boat.  After 18 days, and a trip down the muddy Illinois and Mississippi, our usually pristine boat was, well, a bit dirty.  I contracted with the marina for a wash.  However, when the wash guy showed up with Soft Scrub with bleach and Dawn (absolutely the best grease cutter), I politely said "I'll do it myself).

Background: Guided Discovery is washed every Friday by Paul Boudos' crew.  It is also waxed twice each season.  For those of you who have been on the boat, you know it is always PRISTINE.

I knew these guys didn't have a clue but I called Paul just to make sure I was not being unreasonable.  Paul confirmed that Soft Scrub and Dawn were ABSOLUTELY the wrong stuff you use.  Bottom line: I spent the next three hours washing the boat myself.  Lot's of work but also fun.

So, as Wednesday, October 20 came to a close, I had a shiny boat with shiny new props, which, unfortunately you cannot see.  They really our handsome.

Post Script: Day 18, like days one through 17, was sunny with light winds and warm temperature. 

Written by Les on October 20.