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Old 23rd September 2010, 11:50 AM   #1
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Join Date: Sep 2010
Location: Boston MA
Posts: 14
Default Rio: tuning and maintenance...

After returning from a water session today, I heard a barely audible air hiss which seemed to be coming from the Rio's daggerboard assembly. This led me to take things apart..., which let to taking other things apart -- which ultimately lead to a few questions:

1. The air hiss was coming from the deck screws which fasten the dagger assembly to the board. I noticed that these screws (4? on each side of the daggerboard slot) do NOT have any type of rubber gasket (as is found on the vent plug screw (O-ring)). Question: is this a bad thing? Should I put a dab of hardware store (100% silicone) caulk on the screw threads before re-fastening? This would create a homemade gasket/O-ring...

2. Out of curiousity, I removed the whole daggerboard assembly. While not heavy, it does have a bit of weight to it. As my skills improve (and desire for speed increases), is it possible to use the Rio with the daggerboard assembly removed?

3. The "tuning" section of the website mentions upgrading the stock 410 "shallow" fin to a longer fin. How noticeable is this upgrade? How does a longer fin effect performance...easier foot steering?

4. The Rio's deck is covered w/ nice EVA padding. I've heard that EVA padding will breakdown over time due to UV exposure, saltwater, etc. Is there any recommended treatment that can be applied to keep the EVA deck from drying out?

Thanks as always -
imbrooks is offline   Reply With Quote
Old 23rd September 2010, 08:52 PM   #2
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Join Date: Aug 2006
Posts: 2,177

Hi Brooks,
Question #1:
Can you give us the enviornmental conditions that led to your Rio M "hissing" at the centerboard trunk
hold down screw (s).
Was the water quite cold and the air on the beach quite warm?
The CB trunk cover screws are supposed to be set in inserts the same as the footstrap screws.
If one or more of the screws has pierced the insert, then water may be getting inside to the foam
core of your board. This is obviously not a good thing.
I think you have a good idea with putting sealer on the screws, but I would not use silicone.
If you are in the USA, see if you can find some Hylomar PL32 M. It will provide a permanent seal on any
leaking screws. I would suggest taking a toothpick and working a little Hylomar down into the holes (all of them) before installing the screws again, the idea being to have the screw force some Hylomar PL33 M
to the bottom of the insert (where it's pierced) to seal that up permanently.
I would also recommend that you remove the vent plug and take a check if there is any water showing at the bottom of the vent plug fitting. If it's dry, replace the vent plug.
If not, use a twisted piece of paper towel as a wick to remove the water from the interior of your board.
The way to do this is to use the rise and fall of ambient temperature.
Close the vent during the nite when it's cool (this will pull the moisture out of the core and nearer to the
vent hole) and then open the vent an insert the paper towel "wick" before the daytime temperatures get real warm the next morning (Say before 9:00 AM). Leave your board in a warm sunny spot to allow the
heat of the day to bring the internal temperature up and drive the water in the core foam up to your wick.
Do this as many times as it takes for the wick to stay dry.
Question #2:
Yes, sailors have taped over or even filled in (with expanding foam) the entire centerboard trunk, but
the real solution is to trade up to a shorter lighter board, or retire your Rio M to being a trainer board for your friends and something you use on light wind days when you cannot plane on something smaller.
Question #3:
The stock 410 Shallow Water fin is OK, but as soon as you want to get planing earlier, and no longer need the centerboard/daggerboard to stay upwind, upgrading to a 48-56 cm vertical pointer fin will significantly improve the upwind and early planing performance of the Rio M.
If you have weeds to deal with, or sail in an area with lots of shallow sand bars, then a 39-48 cm weed fin
would be the optimum fin to have.
Question #4:
The EVA deck covering will fade over time, but there is no "treatment" that I know of that will prevent this.
I have Starts that are now >10 years old, and other than fading of the blue color, the EVA deck is still doing well.
A bigger problem, on the Rio line of boards is having small "chips" in the EVA (on the rails especially).
You can use a contact cement (try to find somehing that's clear) to glue the chip back in place.
Hope this helps,
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Old 24th September 2010, 10:46 AM   #3
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Join Date: Sep 2010
Location: Boston MA
Posts: 14

Hi Roger:

You asked if the conditions were hot air temp, cold water temp? Yes..., it was an unseasonably warm fall day (87F) and the ocean temp was 63F. So, could you explain what forces were at play, re: causing air to bleed/hiss out of my board?

I tried the paper towel trick you suggested...all seems dry. Will try again tomorrow, but hopefully the result will be the same (dry).

Will look for the Hylomar. Is that something available in a marine/boating store, or an auto parts store?

Thanks -
imbrooks is offline   Reply With Quote
Old 24th September 2010, 11:38 AM   #4
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Join Date: Aug 2006
Posts: 2,177

Hi Brooks,
The forces involved are simple thermal expansion of the air inside your board.
As long as there is a positive pressure inside, you are OK.
The worries come when you have the board all warmed up on the inside and then place it in cold water.
The core temp drops and creates a partial vacuum inside (if your vent plug O ring is doing it's job).
If there are any open holes to the atmosphere anywhere on your board (vent plug w bad Oring or overtightened), dings through all the layers of the skin, or centerboard cover plate screws that have pierced
the inserts, then water can be drawn into the core of the board by the negative pressure (vacuum) inside.
If there was no water in at the bottom of the vent plug you probably do not have any issue with water in your board.
Hylomar (or a Permatex product that claims to be the same) is available in auto parts stores.
I would take the CB cover off and put a little hylomar on the bottom of the cover first, just to make sure that the Hylomar will not damage the plastic. It's a super strong sealant (kinda expensive, but worth every penny when you need to really seal something) and putting a little around the screw holes, and on the screws should seal up any potential leaks for good!
You could use some marine caulking compound as well, but stay away from silicone based products.
Silicone anything is not what you want around your boards and rigs. Once applied, it creeps into everything at almost a molecular level. Once in, there's no way to get it out or ever make anything (paint/
adhesives/primers/ conversion coatings/phosphatizing/etc.) stick where the silicone has been.
We used to bake aluminum castings at nearly their heat treating temperatures to try to "boil off" silicone
sealers that the uneducated had applied. This worked some of the time.
Hope this helps,

Last edited by Roger; 24th September 2010 at 08:40 PM.
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