Prop scan scheduled for Carver 405

[km1125]

Correct me if I am wrong but I thought lapping was only required when new or if the prop and/or shaft was replaced and now required to be lapped (adjusted) once more. As an example, a damaged prop removed for repair and reinstalled does not require lapping.

It may not be REQUIRED to be lapped, however lapping is always a good check to make sure you have the best fit possible.

I don't know if they always do it, but when I had my props redone (couple times) they also ran a light ream on the taper and recommended I lapped when I was refitting them.

[Midnight Sun]

If they ream the taper then they definitely need to be lapped as the seating surface has now changed.

[bud37]

One other thing to add would be at least check the fit with magic marker or machine blue , never know but the contact surface might be just fine.....honestly you never know what someone has done before you, cheap insurance, its the taper that keeps the prop on, so best be right...them brass things aint cheap...now which way do those damn nuts go on, hmmm.......

[mjk1040]

A 2 point puller and a little MAP gas torch will pop those props right off. Oh yea, leave a nut on the shaft until they pop free. Mike

[Midnight Sun]

While we are on the subject of props. Is it a good or bad idea to use marine grade anti seize on the shafts where the prop sits?

[Viper]

Don't put anything like grease or anti-seize on the taper before installing the prop. I use WD40 then wipe most of it off. That's enough to prevent the prop from jamming part way up the taper while you're tightening.

The small nut always goes on first. Wait, let me clarify; you put the prop on, then tighten it up with the large nut, then remove the nut, install the small nut and tighten it, then install the large nut. Having said that, I bet if you scoped out the boats in your marina, you'd find the opposite to be the case where the large nut has been installed before the small nut in 90% of boats, even those fresh off the assembly line. This is incorrect though some will argue to the contrary.

[Viper]

For smaller props I use a puller similar to this:
http://marinepropellers.com/propellers/index.php?route=product/product&path=64_77&product_id=189

For a larger prop, I use this: it allows you to pull 3, 4 and 5 blade props. For even larger props, there is a larger unit that incorporates chains.
http://marinepropellers.com/propellers/index.php?route=product/product&path=64_84&product_id=244

For the largest props I work with, I use this type of puller if the prop is designed for it:
http://marinepropellers.com/propellers/index.php?route=product/product&path=64_80&product_id=210

As mentioned before, pulling props can be very dangerous. Keep our hands clear, wear eye protection, and always always leave one of the nuts threaded on at the end of the thread so it prevents the prop from flying off and injuring you.

[dsolo]

A scan was preformed on Monday at Holland Propeller. Attached photos show both line and bar graphs of the LH and RH prop. Each blade was scanned 6 places to measure the blade's pitch. Each blade is identified on the graph with a letter. ABCD The design pitch for each prop is 21. All measurements are graphed +(-) to the design pitch of 21. You can see individual blade scanned profiles and a collective summary. The summary is showing the overall pitch of all 4 blades as the mean and the deviation, which is the sum of differences of each blade. More on the results later

The design diameter is 22". There are no graphs to show what was found. I will share the results on this measurement next.

Let's get this uploaded.

[dsolo]

The first prop scanned (RH) looked promising. You can see this on the graphs labeled on the lower right order with RH. Overall blade pitch average was within the allowable tolerance. The blade had been reworked once by Grand Haven Propeller. The technician could ID the rework shop based on a stamp located on the face of the base.

The LH prop is another story. Looking at the graphs tells the story. It had 2 previous repairs. In those repairs the blades must have had blade edge damage for the blades were filed down creating over a 1/4" difference between blades. Holland Propeller stated beyond repair in current condition. What is interesting is during the survey in October a small vibration was detected while observing the port shaft down below. This was the LH prop. This was to be checked after launch in the spring.

There is a lot of data and much more than can be observed physical. Although my outcome is less than desirable, I now have data to help in making a decision going forward. Worth the drive and time.

I will not go into details regarding the input and sell job given during the visit to Holland Propeller. I will keep it to I am glad I did my research on prop supplier options and prices.

I have contacted Carver for original manufacturer and their part numbers. They are Michigan Wheel, 22/21, bronze props. I have decided to purchase new props and will see if my current units can be repaired as backups? There are other shops to try.

Now onto the starts. My dial inicator and stand will arrive tomorrow. I have a tech lined up to help with the setup and measurements.

Enjoy the pictures.

Thanks to Viber for his advice on looking into things with such detail and analysis.

[Viper]

Qr Bbpost.... I now have data to help in making a decision going forward. Worth the drive and time.....

I bet the 240 mile trip seems insignificant now! Just the knowledge you've gained and now peace of mind is priceless.