[C320-list] Thru Hull Failure

[John Frost]

Very interesting thought Jim.
That had not even occurred to me because of our weather.
The boat never left the water and I ran pink stuff through the fitting in
the Fall and closed the valve while it was flowing.
We got a little surface ice (very unusual) but this fitting is well down in
the water. I left a small anti freeze heater running nearby.
I surely hope it was not that because then the rest of the fittings (and
most of the other boats here here) would be vulnerable to another failure. I
will try to send photos of the failure to Forespar to get their opinion. 

Looking at their web site I did just learn something I had forgotten:

"All MARELON® integrated valves have a removable plug in the handle (white
cap with loop). This plug is made to fit into the external thru-hull
(non-screened style only). In an emergency, this plug can be placed in the
thru-hull (water pressure will keep it in) and the valve disassembled while
the boat is in the water. Someone must get wet, but the boat does not need
to be hauled for valve repairs. By tying a lanyard to the cap, you need only
get wet once."

Happy Sailing!

John
2007 C320MKII
Hull 1118
Guntersville, AL




-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of jim brown
Sent: Monday, April 26, 2010 2:37 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Thru Hull Failure

Any possibility the failure was caused by freezing? I know you got snow this
year and it was below freezing in the deep south for several days at a time.
Probably would happen only if the boat was our of the water during the
freezing weather. 

Jim Brown

--- On Sun, 4/25/10, John Frost <john at frostnet.net> wrote:

From: John Frost <john at frostnet.net>
Subject: [C320-list] Thru Hull Failure
To: c320-list at catalina320.org
Date: Sunday, April 25, 2010, 12:40 PM

We had a scary incident on our 3 year old boat last weekend.

While motoring towards home, I lifted the starboard interior seat to stow an
item and was greeted with a garden hose spray of lake water.

It was shooting out the side of the holding tank thru hull, which is
normally wired shut.

I thought, no problem, I will cover it with my thumb, then put one of the
plugs I have in.

Unfortunately the handle  had broken free from the ball valve and left a
very irregular hole that I couldn't plug. All attempts just made it gush in
a different direction.

I had my wife go to warp drive in the direction of our marina, where a crane
resides.

As the water rose, I found that the broken handle did a partial job of
stemming the tide if held in place just right.

I was able to tape that in place and the bilge pump was keeping up as we
came screaming up to the marina.

 

Lots of luck helped. I had just replaced the bilge pump which had been dead
all winter. We were on board when it happened. The crane had just that day
returned from a week of repairs.

Best of all, my marina operator took my urgent call and had the lift ready
before I arrived.

 

Now to the apparent cause. The thru hull is by Forespar and made of Delrin.
It is UL certified and looks like new and turns freely. 

The failure mode was pulling out of the shaft and acorn nut that is molded
into the ball valve. This allowed the handle to shoot out opening up the
valve.

Forespar engineer was incredulous and said it was tested to 150 pounds and
could not break unless I stood on it trying to turn it the wrong way. I
assured him that was not the case.

After think for a bit, I think I found the cause.  I had put a plastic wire
tie LOOSELY around the valve handle and the large adjacent holding tank hose
in case I was stopped for an environmental inspection.

It appears that the adjacent hose had been vibrating (while under power). It
apparently tugged on the wire tie in a direction perpendicular to the normal
rotation force and eventually pulled the valve apart.

Lessons: 

1)      Don't let anything touch your thru hull handles, not even a locking
plastic wire tie.

2)      Check your bilge pump regularly and replace immediately if it dies

3)      Stay friends with your marina operator

 

By the way, Forespar sent a new valve for free

 

 

Happy Sailing!

 

John

2007 C320MKII

Hull 1118

Guntersville, AL