How do you prevent barnacles from growing on the stainless shaft and bronze
prop? I have a mooring in Brunswick, Maine. When the boat was pulled last fall,
the shaft and prop were completely covered and had to be scraped off.
TOM NEALE: For more than 40 years I’ve been looking for a paint or anything else that
will stop barnacles from growing on my strut, shaft, and props. I haven’t found anything
that works to my satisfaction as much as a regular program of diving and scraping. There
are some rather expensive products available, and I’ve used some, but I prefer the manual
method. I even painted on STP Oil Treatment one spring years ago when many of the local
Chesapeake Bay watermen were swearing by it. Examples of products that some have found
helpful are Propspeed and zinc paint such as Pettit’s Barnacle Barrier, or
generic “cold galvanizing” sprays. Copper-based paint on running gear
can result in electrical interaction, doesn’t stay on well, and can impair
Part of the problem is the constant abrasion you get on the prop
from particulates in the water when the boat is running. Some people
cover their prop(s) when they’re not running the boat with a plastic garbage bag with a trip string so that they can easily pull it off before getting
underway. But this is a hassle, probably involves diving at least to do the
install, and you wouldn’t want the bag to come loose and float away.
If your boat is in current with a lot of nutrients flowing by, this will
greatly accelerate the growth. And warmer water also usually results
in more rapid growth. I dive, either free diving or with a Brownie’s
Third Lung. If you keep up with it, the job
isn’t bad, but you must know what you’re
doing in and under the water and be in
good health. If you don’t want to dive, there
are usually commercial divers around and
the cost of hiring them may well be worth
it when you consider the extra cost of fuel
when your props, strut, and shaft are fouled.
If someone has a tried-and-true solution, meaning at least a full season with a
lot of running and little or no fouling, and
repeated success over more than one season,
please email us and share the good news.
WHICH WAY TO WRENCH?
I need to tighten the packing around the propeller shaft. It has a locking nut, and a nut
to compress the packing. Looking toward
the stern from the engine, does the lock nut
turn clockwise or counter clockwise? Does it
depend on the shaft rotation? My prop walk
is to starboard.
DON CASEY: The rotation of the shaft
has no impact. Looking toward the stern
from the engine, the lock nut is going to
turn clockwise to loosen it. Conversely,
the packing nut is going to tighten when
turned clockwise, because clockwise moves
both nuts toward the stern. Be sure to use
two wrenches, one holding the packing nut
when you release (or tighten) the lock nut.
You might also need a pipe wrench to hold
the box at the flange that sits on the stern
hose to keep the box from spinning inside
the hose if the packing nut is stiff. Except for
access, this is usually a pretty easy job that
goes off without a hitch.
REPLACE OR NOT TO REPLACE,
THAT IS THE QUESTION.
I read “Avoid Getting Hosed” in your
February 2014 issue. I installed a new engine
in my boat 11 years ago with SAE J1527
alcohol-resistant hoses. The local dealer says
I should replace them after 10 years if I use
ethanol fuel, which I do. Is it really time?
PRACTICAL BOATER | ASK THE EXPERTS
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