Barnacles on shaft - Page 3 - SailNet Community
LinkBack Thread Tools
post #21 of 23 Old 03-02-2009
Senior Member
Maine Sail's Avatar
Join Date: Jan 2003
Location: Maine Coast
Posts: 6,029
Thanks: 20
Thanked 250 Times in 193 Posts
Rep Power: 16

Originally Posted by Idiens View Post
When I first had my boat, I was told it was no use painting antifouling onto the shaft and propeller as is would simply be spun off. I heard tales of lanolin and all sorts of solutions. After the first season with my new expensive MaxProp coming out covered in barnacles, I had it cleaned and burnished and tried lanolin. The next year, I just cleaned off the barnacles and antifouled it. Antifouling paint may not stick on a new burnished propeller blade but it sure sticks on the residue left by barnacles. Since then the antifouling sticks and the barnacles don't.

I read somewhere that scientists are trying to isolate and manufacture barnacle glue, apparently its the strongest known adhesive. It sets underwater too.

Please, please, please do not use a copper base anti-fouling on a prop. While the Max-Prop is made of Nibral, PYI does not recommend the use of a copper based anti-fouling paint as it can cause galvanic issues!! NiBrAl is Nickel, Bronze, Aluminum.

Many props are made of Manganese Bronze, though some like the Max-Prop are NiBrAl. Manganse Bronze has a considerable amount of zinc in it depending upon the composition used to make the prop. Most marine grade Manganse Bronze is comprised of roughly 58% Copper, 39% zinc, 1% iron, 1% tin. Though different alloy compositions of Manganese Bronze can see zinc content as low as 25% and as high as 39%. The copper in bottom paint can lead to de-zincification of a Manganese Bronze prop which is not good for it.

Thru-hulls & seacocks are generally, and I use generally carefully as who knows what's coming out of China these days, made from a very low zinc content bronze. This Bronze for valves and thru-hulls is usually referred to as Silicon Bronze and is comprised of roughly 96% copper 3% silicon 1% Manganese. Again, who knows what is what these days so a call to a manufacturer is sometimes a good idea. Silicon Bronze has virtually no zinc so should not suffer from de-zincification like Manganses Bronze or Tobin Bronze. Painting thru-hulls should pose minimal threat if they are in-fact made from silicon bronze..

Prop shafts made of bronze were mostly made from Tobin Bronze which also has a higher zinc content and also does not like copper anti-fouling paints. If you paint a Bronze prop shaft or prop you should really keep up with your zincs so the zinc in the shaft or prop does not become the sacrificial material. better yet it may be wise to use a paint that is safe for underwater metals..

Bronzes are not all the same and there are many different grades of bronze that really should almost be called a brass due to the zinc content but because of the added tin or other alloys they are referred to as bronze instead of brass. I've personally never understood why most props have such a high zinc content and are made from Manganse Bronze and not something with more corrosion resistance...?

I paint my thru-hulls but not my prop, shaft or strut..

-Maine Sail / CS-36T

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Images In Posts Property of Compass Marine Inc.

Last edited by Maine Sail; 03-02-2009 at 03:50 PM.
Maine Sail is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #22 of 23 Old 03-02-2009
Senior Member
Join Date: Dec 2008
Posts: 715
Thanks: 1
Thanked 6 Times in 6 Posts
Rep Power: 7
Pettit Zinc Spray

I have a max prop on my boat for the past 24 years and have tried all sorts of things to keep it clean including a labratory grease which seem to promote barnacle growth rather than deplete it. For the past 10 years I've been using a hard bottom paint, but I do prep it with a underwater primer before application. This includes first sanding the prop, wipeing down with a solvent, then applying interlux vinyl lux primewash and then the primocon primer before the putting a hard bottom paint on. I keep the boat in the Cheaspeake and haul out just every two or three years diving on the boat maybe once a season with minimual cleaning. The boat is used heavily throughout the year only sitting in the slip during the winter months. It is a PITA to prep that prop and I hear that Max Prop is recommending the use of the Pettit Zinc Spray. I am thinking about switching since it seems like a easier application, but I'm not sure if I can get multi season use out of that product. The jury is still out...
lancelot9898 is offline  
Quote Quick Reply Share with Facebook
post #23 of 23 Old 03-02-2009
ASA and PSIA Instructor
Join Date: Apr 2000
Posts: 3,630
Thanks: 8
Thanked 27 Times in 27 Posts
Rep Power: 16
Originally Posted by lancelot9898 View Post
I have a max prop on my boat ... of the Pettit Zinc Spray. I am thinking about switching since it seems like a easier application, but I'm not sure if I can get multi season use out of that product. The jury is still out...
Three coats is good for a new England season, but I would not think one application would still be good through a second New England season. several regards...
sailingfool is offline  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pacific Seacraft 34 ljbabin Gear & Maintenance 10 06-06-2009 12:18 PM
PSS shaft seal Windborn Gear & Maintenance 26 02-01-2009 11:10 PM
Propeller Shaft "Flaking" tcase10 Gear & Maintenance 6 08-02-2008 01:02 PM
Shaft replacement or ''the shaft''? foxglove Gear & Maintenance 4 08-19-2006 12:16 AM
The Stuffing Box and Stern Tube Tom Wood Gear and Maintenance Articles 0 04-27-1999 09:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome