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Preventing Hydrolysis
by
Steve Horsfall
I have a 13 year-old,
20-foot fiberglass boat. I will be keeping it in fresh water
for five or six months. The bottom has never been painted.
Will covering the bottom with anti-fouling paint (VC17) help
prevent hydrolysis? I know it will help growth and staining,
but I can't seem to get a straight answer about hydrolysis
prevention. Since the boat is 13 years old, with no sign of
hydrolysis, I have been told to apply a couple coats of good
wax that would act as a barrier like the anti-fouling paint.
Is this right?
I'd rather not go through the sanding, priming and painting
process every year, if it's not necessary.
J. Preston (e-mail)
Waxes or bottom paints are effective. While painting may
seem like more work, when you add the waxing time to the fall
scrubbing time, I would choose the painting process.
If you decide to paint, there's a very specific process to
paint fiberglass for the first time (which is even more work).
But after this three-step process (in following years) it
only requires minimum sanding and one coat of paint to renew
the anti-fouling capabilities.
ONE MORE QUESTION
Actually we just purchased this model (13 year-old, 20-foot
fiberglass boat) at the end of last year, so we are very new
to boating. I hooked up the earmuffs and hose, then started
the boat for the first time this year. There was water coming
out of the vents at the top of the outdrive, where it enters
the rear of the boat and into the engine. I remember seeing
this last year. However, there was also a trickle of water
coming out of the propeller. I believe this is the exhaust.
If this is the exhaust, is this normal? What I do know is
water in the lower unit is bad. The water at the top of the
outdrive was warm, that tells me it's the water used to cool
the engine which seems normal. However, the trickle of water
coming out from the propeller was cold and seemed to be just
the raw water from the hose. The outdrive is an Alpha One
MerCruiser.
J. Preston (e-mail)
Water coming out the exhaust is usually normal. Once the
engine is up to speed, most of the exhaust comes out through
the propeller and it's very hot, hence more water flows through
this area once you are underway.
One thing though, when you're running the engine on the earmuffs,
if you leave it on long enough for the engine to reach operating
temperature and the thermostat opens, the water at the propeller
should be warmer too.
You are right, water in the lower unit is bad. After testing,
let the unit sit overnight and remove the lower lube screw
from the drive and there should be no water there. The oil
in the drive should be dark, not white. Some air bubbles in
the oil are OK, but if it is white, it usually means water
and the unit should be pressure-tested to locate the leak.
PERFORMANCE SEEKER
I have a Regal 2150 LSR with a stepped hull that is powered
by a 4.3L 205 hp MerCruiser, spinning a three-blade 21-inch
pitch aluminum prop which delivers 4800 rpm. I had a MerCruiser
HighFive 23-inch pitch prop on the boat that reached 4200
rpm.
I would like to change the prop to either a Mercury Mirage
Plus, Mercury Revolution 4 or Mercury HighFive in order to
gain performance without loosing top end speed. Which prop
and pitch do you recommend and what would my maximum rpm be?
You are my last hope.
K. Whitford (e-mail)
The prop you are currently using is pretty good. The HighFive
with a 21-inch pitch would be slightly better. I would not
recommend the Mirage Plus for your application.
In a nutshell, I think your existing set up is as good as
it gets, but the HighFive may get you out of the hole a bit
faster.
Sorry, I have no experience with the Revolution 4.
(Got
a question, a problem, or do you need some info on elusive
engine or boating equipment? Drop me a line c/o Power Boating
Canada, fax me at (613) 236-0700 or e-mail:
stephen.horsfall@sympatico.ca) (Top)
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