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Old 14th August 2008, 03:50 AM   #1
AlexV
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Default Air vent leak on a Kombat 106

Hi there,

I have a Kombat 106lt model of 2006. A few days ago as I was getting ready to get into the water, I noticed water coming out of the air vent which was closed. After unscrewing the valve, I noticed the O ring was in a bad shape. I put the board in the sun and I let the water boil and evaporate through the valve.
Then, I replaced the O ring with another O shaped black rubber fitting on the screw (probably not an O ring) and after 1 hour on the water, much more water was evaporating through my open air vent afterwards.


Is the damage on the board from the water that came in, repairable?

Does this look like a valve problem or the board might have a hole somewhere else? If we are talking about a valve problem, is it important to use exclusively O ring rubber seal? How often should I replace the O ring?

How can I test if, after replacing the O ring with another O ring the vent is watertight?

How can I test if there is a hole somewhere else on the board? (Other than the vent problem, the board is intact and in a very good shape, no scratches, hits etc.)

How can I extract all water or moisture from the interior of the board? Is there some sort of test to see if there is still water left inside? ( I haven't weighted the board before this incident, so I cannot compare weights)


Thank you for reading this. Apologies for the long list of questions. I am very frustrated, since this board is my first -and expensive- buy of a new board and I was very happy with it until now.
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Old 14th August 2008, 09:31 AM   #2
Roger
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Hi Alex,
Having a leaking vent plug is for sure not a good thing, but it may not be
as disastrous and detrimental to your board as you are currently thinking.
I’ll try to answer your questions one at a time and give you some solutions
To dry up the interior of your board and once dry, keep it sealed.

I have a Kombat 106lt model of 2006. A few days ago as I was getting ready to get into the water, I noticed water coming out of the air vent which was closed. After unscrewing the valve, I noticed the O ring was in a bad shape. I put the board in the sun and I let the water boil and evaporate through the valve.
Good thinking! The only thing you could have done to improve this would be to make a “wick” from some absorbent paper toweling. Roll the paper towel into a kinda cone shape
And stick the pointed end down into the vent hole all the way to the bottom if possible.
If the towel sucks out a lot of water, replace it.
The heat inside your board on a warm day will indeed cause the water to vaporize and the moist air will be pushed out of the interior foam of your board.

Then, I replaced the O ring with another O shaped black rubber fitting on the screw (probably not an O ring) and after 1 hour on the water, much more water was evaporating through my open air vent afterwards.
Hard to say if the vent plug was still leaking or not, but if you put something other than the correct size O-ring in the vent plug chances are it did not seal.
Part of the problem with the O-ring is sailors want to tighten them up way too much.
Just put in a new O-ring and snug it down until it slightly compresses the O-ring and tight
enough so the plug won’t back out.
Overtightening the O-ring just crushes and deforms it, and ruins it’s sealing properties.

Is the damage on the board from the water that came in, repairable?
You should be able to get most of the water back out so you can use your board this summer, and then when you store it for the winter, look for a very low humidity storage
place so it can dry out over a longer period of time. Keep it inside your home where it’s warm and dry if possible. If not, store it near something warm that circulates the air.

Does this look like a valve problem or the board might have a hole somewhere else? If we are talking about a valve problem, is it important to use exclusively O ring rubber seal? How often should I replace the O ring?
First you need to get as much water as possible out of your board.
Then you can test around the fin box and mast box to check for leaks.

How can I test if, after replacing the O ring with another O ring the vent is watertight?
You can use the “change in temperature” from morning to the highest temperature time during the day.
With a new O-ring (apply some soap to the threads of the plug and wet your fingers and put some soap on the o-ring before installation) properly seated, in the morning, as the day warms up, you can slightly loosen the vent plug.
If the O-ring is sealing correctly, you will get a little hiss of pressurized air that builds up inside your board.
Do not leave the vent plug tight for a while during the heat of the day until you are sure you have as much water as possible out of the core of your board.
As soon as you come off the water, turn your board over to let the water drain out around the plug the turn it right side up in the sun with the vent plug out so that any water inside will be vaporized.

How can I test if there is a hole somewhere else on the board? (Other than the vent problem, the board is intact and in a very good shape, no scratches, hits etc.)
The only likely places for there to be other leaks are the fin box and the mast box as these are the only places that extend from the outside and into the core of your board.
To test them, make a solution of soapy water and put your board in the direct sun for half an hour with the vent plug closed. The board will develop internal pressure and you can dribble some of the soap mixture on the mast box and fin box to see if any bubble develop.
If you get bubbles, that’s where the leak is.
You can also use the soapy water to check to see if your vent plug is leaking.

How can I extract all water or moisture from the interior of the board? Is there some sort of test to see if there is still water left inside? ( I haven't weighted the board before this incident, so I cannot compare weights)
As I said, unless you are a professional with a vacuum pump; vacuum regulator; and you know how to use both, using thermal expansion is the best method available to you to get the water out of your board.
Place your board in the direct sun, with the vent plug out and a wick stuck down the hole.
Change the wick frequently!
When you aren’t getting any more water at the bottom of the hole, you’ve gotten about all the water out that you are going to. Do this with the deck of the board facing up into the sun. If you turn it over, since warm moist air rises, you would be spreading the water vapor
inside your board toward the bottom. So remember vent plug out, deck up, in the direct sun.
You may have to do this several times to get all the water out.
If you are not sure if the vent plug is sealing correctly, I’d suggest putting a piece of duct tape over the plugged vent fitting when you are taking the board on the water. The tape will add another barrier to water intrusion.


Thank you for reading this. Apologies for the long list of questions. I am very frustrated, since this board is my first -and expensive- buy of a new board and I was very happy with it until now.
If you live in the Western Part of the USA, you could ship your board to Eva Holiman during the winter for a complete vacuum drying out.
Check out http://www.boardlady.com /water.htm for more information on drying out your board.

Last edited by Roger; 14th August 2008 at 10:00 AM.
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Old 15th August 2008, 02:42 AM   #3
AlexV
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Dear Roger,

Thank you for the information. The board is currently drying with a "wick" made of kitchen towel paper. I live in Crete, Greece so I guess it is not possible to send the board to Eva Holiman (very interesting link). But I will try to dry the board as much as possible during august. I estimate that about 80% of the moisture will be out of there in a couple of days. After that I will run all the leaking tests you suggested.
Thanks again.
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Old 15th August 2008, 03:36 AM   #4
Roger
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Hi Alex,
I think until you get the chance to really dry out your board, I would strongly suggest that you use the vent plug all the time.
Loosen it whenever you aren't going on the water, and tighten it whenever you do go on the water.
This "cycling" of the vent plug can do alot toward getting the moisture out and ensuring that your board does not suffer any internal damage from heat build up.
If you know anyone with a vacuum pump and regulator, that's the best way to dry one out, but you only need a partial vacuum.
I don't know the numbers but as you can see from Eva's website, she discovered the hard way what too much vacuum can do. She had a customers board "implode".
So a mild vacuum with a regulator and a relief valve should be perfectly safe and Eva might give you the safe numbers if you ask her in an email.
Hope this helps,
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Old 15th August 2008, 08:56 AM   #5
Brian S
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Hi Roger,
As long as you're on this topic, do you know what the correct dimensions of a new vent screw O-ring should be? I'm thinking that I'll just replace all mine as a matter of maintenance, and I know they're cheap. However, if I take an old one off to measure, it will already be distorted.
Brian
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Old 15th August 2008, 09:07 AM   #6
Roger
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Hi Brian,
Hmmmm.... that would be good info to have.
Not tonite, but I'll measure one up with my precision vernier
caliper tomorrow and report back.
Thanks for the input!
R
P.S. I've also asked Eva H. if she can give me the magic "not to exceed" number
for drying out boards.
I might just get my vacuum pump out and start drying things out and doing some
repairs.
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Old 15th August 2008, 11:19 PM   #7
Roger
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Hi Brian,
I measured an O-ring out of my spare parts box today and here's what I got.
Metric O-rings are measured/specified/classified by the Inside Diameter (ID) and the Cross Section (CS).
The O-ring from my kit is 2.0 mm CS and 8.5 mm ID.
The part number is therefore M2x8.5.
The Outside Diameter (while not specified) is the 8.5 mm + 4.0 mm or 12.00-12.20 mm.
I found a wholesale distributor online with a very nice chart of metric O-Rings.
I guess you could call them and see who distributes their Metric products in your area.
Here's the link to the chart:
http://www.oringswest.com/metric-o-rings.html
Hope this helps,
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Old 16th August 2008, 09:25 AM   #8
Roger
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Hi Guys,
I asked Eva Holiman (the boardlady.com) about safe vacuum values to dry boards.
It seems to depend alot on the construction and how old the board is.
Older Mistrals are only safe to about 6 inHG.
Newer Starboards (Technora construction) can handle almost 12 inHG.
Most modern Cobra Sandwich construction (Technora/Wood/Dram) can take 10 inHg safely.
So, the suggestion is start at 6 inHG (152.4 torr....20.318 Kilopascal) and if you hear the water gurgling, don't increase it more until the gurgle stops.
Add a little more vacuum and if it gurgles some more, leave the vacuum at that level until the gurgling stops.
When you get to about 8-10 in HG with no gurgles, your board is as dry inside as vacuum is going to make it.
Keep a close look at any "soft spots" on the deck and bottom as if you go too high they may "cave in".
Hope this helps, and Thanks again Eva!

Last edited by Roger; 16th August 2008 at 10:28 AM.
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Old 18th August 2008, 07:56 PM   #9
Brian S
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Roger,
Thanks for the O-ring info. Good info! Assuming most vent plugs are the same, I'm going to buy spares and just change them out regularly.
Brina
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Old 19th August 2008, 04:23 PM   #10
AlexV
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Default Air valve not watertight

Hi Roger,

After a few days in the hot sun, I think that the board is as dry as it can get. It weights 7.8kg with starboard's catalog weight at 7,6kg and for sure I am in the margin of +-6%.
Also, by "listening" to the board I don't hear anything anymore, and the kitchen paper in the vent comes out completely dry.

But I see that the valve itself is not watertight: Today I put a proper O ring to the valve and after putting soap bubbles above the closed air plug, I saw air coming out from the seam between the screw and the board . I tested it with the screw more tight and more loose, and I noticed that the tighter the screw, the leak is weaker. But the thing is, the vent is not watertight. I took the screw out and tested the "walls" of the vent to see if the leak is coming from there, but no.

Is it possible that the geometry of the vent changed due to pressure from the interior of the board?
Is there in your opinion anything else I can do before taking the board to a professional?


Thanks again,
Alex
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