View Full Version : Valve Screws - Suggestion for a better design
12th March 2007, 07:33 AM
I'm hopeless at remembering to do-up/undo the valve screw on my board when I go out sailing or go travelling.
The problem is that its hard to see if the screw is loose or tight. It not a good idea to take it out cos you end up losing it
Why not have a big brightly coloured lever that would stand prone from the board surface when open, instead of a small screw that needs a screw driver to open and close.
Or attach the screw to the board with a tether so you can take it out and leave it dangling as a reminder.
Better still, the mast foot base or fin box could be designed in some way as to act as a bung for the breather hole.
Just a suggestion of course to a problem that I know I and many sailors have.
I'm going to buy a Starboard EVO soon (just as soon as my wife lets me!)
12th March 2007, 02:51 PM
It is a shame that the vent screw is nit fitted into the mast track. If it was carefully positioned there then you could not get the deck plate in without first tightening the screw.
Having said that, I rarely undo mine.
12th March 2007, 02:53 PM
sorry to disagree... but I really hope that neither Starboard nor other makers will give up the simple old srew design. Other solutions do show up at times, but a simple screw with an O-ring will work flawlessly and give no problems. Remember that the air valve is continuously exposed to salt water, sun rays, sand... personally I would trust no mechanism to do that job properly over time. At least one manufacturer uses Gore-Tex valves, but I don't trust them and if I will decide to buy a board from that manufacturer, I will ask to fit a classic screw instead.
Rather, and expecially if you tend to forget about it, why do you screw and unscrew the valve every time? If I was in your shoes, I'd rather close it at seanon's start, keep it closed at all times and open it again at season's end, except in the case of a plane travel or exposure to major pressure (approaching/leaving of thunderstorms or deep fronts) and heat changes.
13th March 2007, 02:00 AM
I've got a pretty solid plan for you that I noticed the Real Wind folks using on their rentals in the Gorge. They have all their boards fitted with Chinook's two point plates. Once the day is over and they are packing everything up, they remove the plugs and insert them down in the hole that the universal attaches to, and then they move the retainer mechanism to a closed position capturing the plug. Until the plug is removed, the universal can't be installed. Really, a fairly sound plan that leaves little to chance.
For myself, I follow geo's plan and never remove plugs unless I'm travelling by plane or through higher elevations. Never a problem this way, but I should note that I carry everything in a light colored van. Also, most of my white boards are stored in insulated bags that further mitigate the affects of elevated temperatures.
13th March 2007, 02:24 AM
I like that idea from Real Wind. I'll have to start doing that with the boards I use two-point plates on. Thanks.
I know my weaknesses. I called up a shop and ordered 20 of those board plugs. They are red in color, so they stand out enough for me to notice when I don't see them.
I usually loosen them up in the coldest/hottest months because I'm paranoid. I've only lost one in the past year, but I doubt I'll run out anytime soon. ;-)
As an aside, I've found myself looking through the bolts in the hardware store to find stainless steel 1/4-20's for my boards. I have quite the collection now. ;-) I'm still missing longer lengths though.
13th March 2007, 07:22 AM
I live in Perth Australia and windsurf all year round. The temperatures here in the summer reach over 40c on some days. My boards are bagged with insulation but go on the roof of the car when I go to the beach. Hence the "plug paranoia".
I don't think your suggestion of opening and closing it once a year would work for me.
The problem is, I feel, the potentially catastrophic effects of forgetting the board plug (both ways), not losing the plug as such.
I've done it once and ruined a board when I sailed with it loose.
I can live with the screw, I just think a way should be worked out that would FORCE the user to check it before sailing.
Real Wind's suggestion was very good, with my new board I will deffinately employ a similar method.
I've heard of some board manufactures employing goretex type membranes over a small hole which sounds good to me.
PS this is from the board maker Blue Juice in Perth....
When I make a board I put the vent plug in the nose area, so if it forgotten to be done up then that area of the board has the highest chance of staying out of the water, you can also see it when sailing which helps remind you to think if it was done up.
CJW leaving it done up all the time means that the board shrinks and expands EVERYDAY with the min and max temps, so after this happening say 730 times(2years)the weakest link in the board which is the bond between the little polystyrene balls pulls apart and the board delams. Ive ripped open many delam boards for repairs and theres a thin layer of beads still stuck the skin of the board.
13th March 2007, 09:53 AM
You can continue with "plug paranoia" for as long as you like.
If your boards are white or a light color on the outside, you can store them on the roof of your car in a reflective bag with little or no worries.
Storing boards INSIDE a hot car on a summers day is where the real problems lie.
Or if you have a board with lots of exposed black carbon fiber on the outside (not covered by paint) or a board painted in a really dark color, it will absorb several times more heat and it would be a good idea to open the vent slightly to eliminate any chance of internal pressure buildup.
But first, Starboard and all the other board manufacturers need to look at the specifications for "o rings, o ring grooves, and proper
O'ring gland joint design.
The current "squash the o'ring" thinking has nothing at all to do with how an O'ring is designed to seal.
I've been over this many times,and if you research my past posts on this subject you will find links to the full realm of O'ring gland design
The way the the windsurfing industry uses o'rings suggests that the designers do not know or care about the difference between a correctly designed O'ring gland joint and a simple gasketed joint.
The current vent plug designs simply "scream" for a fiber or high durometer rubber GASKET, not an O'ring.
Actually, if the vent plugs incorporated a properely designed O'ring groove under the head of the plug, the O'rings would last virtually forever, and I'd be alot more worried about internal pressure build up as the vent plugs would actually seal, rather than acting as cheap substitute for a "safety valve" The pressure builds up a little and the "squashed" o'ring begins to vent.
Then you put your board in much cooler water, and the squashed O'ring allows water to seep in when the internal vacuum drops low enough.
The Gore Tex vents work pretty weill, in FRESH WATER, but like everything made of/with Goretex. the plug needs to be rinsed in fresh water to prevent salt build up which fills the micro-pores in the goretex membrane until the Goretex fails to work the way it was designed.
Hope this helps,
13th March 2007, 02:09 PM
very interesting points.
Actually I am not much worried about the O-ring being used in the wrong way as it actually acts, as you delineated, as a safety valve, letting some pressure go when the board is heated and letting just a little water in actually when it is cooled/depressurized.
What I really don't like about the O-ring system (even if as a graduated engineer I don't like much such incorrect solutions) is the fact that if, or better say: "when", some sand gets in the hole, the O-ring will not even came close to seal anything, plus it is not easy to detect nor to clean it.
Maybe a good solution would be to use tapered self-sealing screws. My first sandwich board, a Phil McGain proto, just had a small self tapping screw in a piece of plastic, no gaskets, and it worked flawlessly.
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