Waxing Hull for Racing - to wax or what? - RC Groups
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Jan 30, 2013, 03:17 AM
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coolmobility's Avatar
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Waxing Hull for Racing - to wax or what?


Do you experienced guys wax your hulls for improved speed or not? In my kayak paddling days a waxed hull was much more slippery and easy to paddle and I'd wax my small yachts before races.

I know in large sized yachts there is discussion re waxed hulls or finely sanded for fastest hulls and antifoul types/preferences. Haven't seen any comments on waxing RC yachts on any thread though...

I'm relatively new to IOM racing and a mate has just reconditioned an identical hull to my Orca (wide planing hull). When he launched it in drifting winds he just walked away from me without any real trimming. I though (hoped) that it was his shiny new paint job versus my old oxidised one. Perhaps waxing my hull would help in below hull speed conditions. When wind picked up I was fully competitive with all in fleet (Actually 2nd overall).

Looking for comments and feedback.

Colin
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Jan 30, 2013, 04:41 AM
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C.5.2 MAINTENANCE
Routine maintenance to the hull such as removing and adding fittings and remote control
equipment, replacing hull patches, painting, polishing, smoothing etc., is permitted
without re-measurement and re-certification provided the compliance with D.2 is not
affected.
Jan 30, 2013, 04:51 AM
Love RC Yachts!!!
Check my post in IOM discussion...

But no, i don't wax, but use a silicone free polish on thd hull, and 1200 wet and dry on the foils and bulb.....
Jan 30, 2013, 06:55 AM
Nirvana 38, Seawind 178
seabee CE's Avatar
Some of the ODOM guys I raced with used RainX on the hulls, not saying is good or bad, just adding another theory.
Jan 30, 2013, 03:01 PM
Kimo
Some of our guys use mold relase wax, one even uses that once a year car wax,while some don't do anything to their hulls. Believe that any difference is in the trimming and s]the skippers skill. As far as sanding the hull the only real difference that I have seen was in the hull finish and no real change in speed. What works on full size boats doesn't always work on models.
I base this on not being able to sail the last 9 months and just watching the guys sailing so I wasn't distracted by sailing.
Jan 30, 2013, 03:43 PM
Big Boats Rule!
boater_dave's Avatar
The next time your mate is sailing with you and walking away, swap rigs. If the increase in speed follows the rig you'll know where the speed comes from. I believe that rig tuning is far more critical in light air than in heavy air. Next most important item would be fin and bulb position/angle/etc. A tiny difference in bulb angle might make up the difference as well. Of course, I'm assuming your hull is fair and doesn't contain giant bulges, cavities, etc and only differs from your friends in surface finish.

Dave
Jan 30, 2013, 05:04 PM
Registered User
The answer to the question is "No". Do not put wax on a sailboat hull. It is slower. To make some very complicated hydrodynamics simple--there is less drag if you have a thin layer of water sticking to the hull rather than water repellent wax. If you want, sand with a fine grit wet/dry sandpaper--900 or above and then polish from time to time. This is a matter of fact, not opinion.
Jan 30, 2013, 05:34 PM
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coolmobility's Avatar
Thanks for the feedback. Now I'm just as confused as I was from big boat discussions.

What is the difference between waxing (with car wax) and polishing?

Wouldn't sanding with 900 or 1200 grit then polishing end up with a smooth surface again?

As a newbie, this forum is filled with great knowledge but seems there are naturally many opinions and few definitive answers. My job to decide on balance of opinions.
Jan 30, 2013, 05:38 PM
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ToniGe23's Avatar
Quote:
Originally Posted by coolmobility
Thanks for the feedback. Now I'm just as confused as I was from big boat discussions.

What is the difference between waxing (with car wax) and polishing?

Wouldn't sanding with 900 or 1200 grit then polishing end up with a smooth surface again?

As a newbie, this forum is filled with great knowledge but seems there are naturally many opinions and few definitive answers. My job to decide on balance of opinions.
The sanding should be done with soapy water to stop the grit paper clogging.
Last edited by ToniGe23; Jan 30, 2013 at 07:03 PM.
Jan 30, 2013, 06:26 PM
Registered User
We are talking about rough/smooth at a very fine level. The idea is that you want to have a level of roughness in your finish sufficient to trap a microscopic layer of water to the hull. This is because the friction difference between water and water is lower than between water and wax (hence less drag). Anything that repels water--like wax--is a bad thing. This is not an "opinion' thing it is established, basic hydrodynamic fact.
Jan 30, 2013, 07:02 PM
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ToniGe23's Avatar
Quote:
Originally Posted by Tom Corbett
We are talking about rough/smooth at a very fine level. The idea is that you want to have a level of roughness in your finish sufficient to trap a microscopic layer of water to the hull. This is because the friction difference between water and water is lower than between water and wax (hence less drag). Anything that repels water--like wax--is a bad thing. This is not an "opinion' thing it is established, basic hydrodynamic fact.
Club member of mine has a Topico an ex Graham Bantock boat, below the water line it's been rubbed back with 1200 grit and it sure is a slippery bugger in light winds!
Jan 30, 2013, 07:31 PM
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coolmobility's Avatar
Thanks for the clarifications. Makes more sense now. Have to get some 1200 grit wet/dry and soapy water and give it a try. Can't do much harm with a light 1200 sand on wetted areas and may wax the deck to get better water shedding.

Thanks again.
Jan 30, 2013, 07:36 PM
Don't lie to my dog.
Gregg28's Avatar
Quote:
Originally Posted by coolmobility
What is the difference between waxing (with car wax) and polishing?
Waxing is adding a microscopic hydrophobic (water repellant) finish. Polishing is just using friction to get a microscopic smooth finish without adding anything.
Jan 30, 2013, 09:01 PM
Suspended Account
Quote:
Originally Posted by coolmobility

What is the difference between waxing (with car wax) and polishing?


Quote:
Originally Posted by bigpat
Check my post in IOM discussion...

But no, i don't wax, but use a silicone free polish on thd hull, and 1200 wet and dry on the foils and bulb.....


The basic difference in the term wax as opposed to polish is more to do with the understanding of each compound used.

Waxing in 1:1 scale generally adds a layer to the outside of the hull & this is OK when considering the size of water molicules..

In R/C terms the water cannot be scaled so waxing would be OUT IMHO.. Then as pat says using a Silicone Free Polish & 1200 builds a perfect finish.

Be mindful of the size as you scale down.. Some people comment that their boats become more twitchy to sudden changes in wind pressure & can tend to round-up easier. Not sure I agree but if the idea is to move easier through the water by reducing friction then it goes as said that movement in ALL directions is improved by the reduced friction... So improved concentration & oveall balance of the boat may be needed.
Jan 31, 2013, 04:23 AM
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KoneWone's Avatar
Quote:
Originally Posted by ToniGe23
Club member of mine has a Topico an ex Graham Bantock boat, below the water line it's been rubbed back with 1200 grit and it sure is a slippery bugger in light winds!
Agree 100% most noticable difference is in light airs. I measured 2 hulls with push test across swimming pool 10 meters (without rigs) 20 times to find average measure between boats touching other side of the pool, then sanded one hull and it made gain of 10 cms !!!

Over 100 meters that = 1 metre


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