I hope this doesn't sound like a dumb question. But I've noticed
what appears to be small cracks in my rudder on my 28 ft sloop. It's a
fiberglass spade rudder. The rudder is approximately four feet in
height. The bottom of the rudder on one side ( no more than a foot and
a half from the bottom edge) is showing small "X"'s and lines about
1.5 to 2 inches in length.
I first noticed them last year, just before launching the boat for
the season. I covered them up with bottom paint since I didn't have
the time to investigate. When the boat came out of the water in the
Fall I began to see these same cracks appearing thru the bottom paint
again.
Does anyone have any experience with this or has seen it before. I'm
thinking that water has penetrated the gelcoat and is leaking out when
the boat is up on the stands during the off season.
If this is the case, anyone have suggestions for the best way to rid
all of the water out of the rudder? Oh, and one other note. This
rudder ( and hull) was stripped down to the gelcoat and had barrier
coat applied in the late 1990's. Water shouldn't be pentrating it al
all.

Frank

Frank:

Sound like something bad may have happened within the rudder core.

See this excellent article on the subject from West System:

http://www.westsystem.com/ewmag/12/rudder.html

MW

On Fri, 18 Jan 2008 10:16:04 -0800 (PST), Frank
wrote:

I hope this doesn't sound like a dumb question. But I've noticed
what appears to be small cracks in my rudder on my 28 ft sloop. It's a
fiberglass spade rudder. The rudder is approximately four feet in
height. The bottom of the rudder on one side ( no more than a foot and
a half from the bottom edge) is showing small "X"'s and lines about
1.5 to 2 inches in length.
I first noticed them last year, just before launching the boat for
the season. I covered them up with bottom paint since I didn't have
the time to investigate. When the boat came out of the water in the
Fall I began to see these same cracks appearing thru the bottom paint
again.
Does anyone have any experience with this or has seen it before. I'm
thinking that water has penetrated the gelcoat and is leaking out when
the boat is up on the stands during the off season.
If this is the case, anyone have suggestions for the best way to rid
all of the water out of the rudder? Oh, and one other note. This
rudder ( and hull) was stripped down to the gelcoat and had barrier
coat applied in the late 1990's. Water shouldn't be pentrating it al
all.

Frank


If the rudder is built with a foam core, covered with glass cloth it
probably has started to absorb water. Try drilling a number of holes
in the cracked area and around it to determine whether water ingress
is your problem. You can fill the holes later with epoxy filler if no
problems are found.

It is common to find foam rudder that have started to absorb water
through almost invisible cracks, holes and voids.

Depending on the extent of any water ingress you may be able to cut
out the saturated portions and glue in new foam and recover with glass
cloth, fair and repaint. Or, you may need to tear the rudder apart and
rebuild it. An honest, competent, fiberglass guy would be a great
asset in checking this.


Bruce-in-Bangkok
(Note:remove underscores
from address for reply)

A surveyor once told me that when he surveyed a boat and found no problems,
he knew that he could "always" find water (moisture meter) in the rudder.
He felt the problem was the penetration of the rudder shaft into the
fiberglass rudder regardless of whether it was a solid layup, foam covered,
wood reinforced etc. The joint is bound to leak due to the loads imposed
and the problematic adhesion of resin to stainless steel. On a different
tack, I once owned a foam core boat with a hollow rudder. It had weep holes
that had to be cleared every fall to allow the accumulated water to drain.
Dave

Frank,

The old line about dumb questions still stands.

What you are describing is the first sign of water in a rudder.
You think it is sealed, but I have news for you - It isn't. No rudder
with a shank will stay sealed indefinitely. If the cracking you are
seeing was closer to the top, it might be the shank material corroding,
but this is most likely water. I could probably tell you more if I knew
the builder.

We need some background here so that both the problem and the method of
repair are clear. (If you know this, stand by, but someone reading this
probably does not.)

In your case, the rudder structure is composed of at least three pieces.
Those a
The metal rudder shank and attaching features. (It is tough to hold the
blade on a straight pipe.)
The blade skin - that is now cracked and has a hole for the shank.
The blade core that fills the skin and attaches it to the shank.

The shank is usually a stainless or bronze pipe (hint - there is a hole
in the middle).

The skin is most often (again, I don't know who built it or when so this
is a generality) a pair of molded pieces.

The core on high production boats is usually PE resin with all manner of
filler (including sawdust) to reduce the amount of resin required and
lighten the final part. This filler material is often pretty weak in
shear, tension or compression, but it is enough to work. If it has much
cellulose fill (sawdust) in the mix, it can behave very much like a
sponge.

These rudders are assembled in what I describe as a giant popsicle
factory. The two skins are set it a mold to hold the shape against the
hydraulic pressure of the uncured filler, the shank is held in place in
the mold by a jig and filler is poured in to level and cured.

Polyester is the cheapest resin out there. It has one small issue with
its lack of adhesive bond strength. In short, the skins are just barely
held on the core. So - when a little water manages to get between the
skin and the core, it waits there until it can freeze. When it freezes,
it makes a little more room for the next seasons water. This processes
repeats until something cracks open and the water can run out. Often
these cracks are visible at haulout and then start to drip in the
spring. The reason that they reappeared through the antifouling paint
is simply because the foil does flex under load and the paint doesn’t
have much tensile strength.

Now, what to do about it....
First examine the rudder. Is there any change in surface profile in the
vicinity of the cracks? I bet there is.
So - drill some holes - tiny - where you see the cracking. I bet water
comes out. There is probably a small void near the center of the X
which is where water first collected. If you drill there and push, you
can make water squirt out. You will need another hole somewhere down
the skin at something more than the radius of the longest arm of the X.
Very little water will come out of this hole, but is it essential to
drain the "bubble".

Repair:
If you can, store the rudder shank down in a heated space for the
winter. You may be surprised by the amount of water that does come out.

Actually repairing the damage is involved, tedious and unnecessary.
Involved because you have to remove all the skin that has lost its bond
to the core and probably resurface the core before creating a new skin.
It will be tedious because however you create the new skin in will
require fairing and finishing that will take much longer than you
currently imagine. This will not get you much in the final analysis as
the poor bond between the shank and core is still going to be an issue
in years to come.

What you want to do is either leave the rudder upside down in the
basement until spring. Or, if you cannot, then after you drill the above
mentioned holes, wrap the blade in aluminum foil. (Is this crazy? - No)
This is to keep the rudder from going through freeze/thaw cycles every
time the sun shines on it or the weather warms above freezing for a
short period. It is no kind of a cure, but it does seem to help.

Finally, at fitout, run some screws into the holes with a little sealer
just to not make a convenient path for water to return. If you race the
boat, use flat head screws but otherwise don’t bother as the will be
harder to find again at the next haulout.

I have repaired, rebuilt or built more than a few rudders, and I’m not
sure if this is the most common problem or if it is grounding/strike
damage. The condition you have is not rare, but if you chase it this
winter, it may be a minor issue for many more seasons.

Matt Colie
Lifelong Waterman, Licensed Marine and Perpetual Sailor
www.southpointechandler.com



Frank wrote:
I hope this doesn't sound like a dumb question. But I've noticed
what appears to be small cracks in my rudder on my 28 ft sloop. It's a
fiberglass spade rudder. The rudder is approximately four feet in
height. The bottom of the rudder on one side ( no more than a foot and
a half from the bottom edge) is showing small "X"'s and lines about
1.5 to 2 inches in length.
I first noticed them last year, just before launching the boat for
the season. I covered them up with bottom paint since I didn't have
the time to investigate. When the boat came out of the water in the
Fall I began to see these same cracks appearing thru the bottom paint
again.
Does anyone have any experience with this or has seen it before. I'm
thinking that water has penetrated the gelcoat and is leaking out when
the boat is up on the stands during the off season.
If this is the case, anyone have suggestions for the best way to rid
all of the water out of the rudder? Oh, and one other note. This
rudder ( and hull) was stripped down to the gelcoat and had barrier
coat applied in the late 1990's. Water shouldn't be penetrating it at
all.

Frank

Frank- there are solvent free epoxies (you want the solvent free
ones for this application!) that will bond to damp or wet
surfaces. Similar to what many folks to when deck cores begin to
delaminate, rot out, etc, you drill lots of holes to drain and dry
as best you can, then begin injecting a water bonding epoxy into
the holes.....

not the 'by the book repair' one would like, but very commonly
done anyway. You are sort of replacing the water with epoxy....

paul oman (beware, I'm a commercial vendor and in the business -
pls filter my suggestions accordingly)



Frank wrote:
I hope this doesn't sound like a dumb question. But I've noticed
what appears to be small cracks in my rudder on my 28 ft sloop. It's a
fiberglass spade rudder. The rudder is approximately four feet in
height. The bottom of the rudder on one side ( no more than a foot and
a half from the bottom edge) is showing small "X"'s and lines about
1.5 to 2 inches in length.
I first noticed them last year, just before launching the boat for
the season. I covered them up with bottom paint since I didn't have
the time to investigate. When the boat came out of the water in the
Fall I began to see these same cracks appearing thru the bottom paint
again.
Does anyone have any experience with this or has seen it before. I'm
thinking that water has penetrated the gelcoat and is leaking out when
the boat is up on the stands during the off season.
If this is the case, anyone have suggestions for the best way to rid
all of the water out of the rudder? Oh, and one other note. This
rudder ( and hull) was stripped down to the gelcoat and had barrier
coat applied in the late 1990's. Water shouldn't be penetrating it at
all.

Frank