Forums > Windsurfing   Gps and Speed talk

polishing bottom of boards ?

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Created by lelos12345 > 9 months ago, 6 Sep 2010
lelos12345
NSW, 453 posts
6 Sep 2010 10:33AM
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love to know thoughts on polishing the bottom of speed boards ... does it make em go faster or just feel nice

Bender
WA, 2038 posts
6 Sep 2010 10:24AM
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I dunno if smooth is faster. Carbon Art boards come with a smooth teflon polished finish and they go pretty quick.

lelos12345
NSW, 453 posts
7 Sep 2010 10:52AM
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I ride CA thats what i thought they look nice and hopefully they go faster

pacman76
QLD, 123 posts
7 Sep 2010 5:27PM
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Used to see Mal Wright at sandy point polishing his boards. I think the community is divided about if this makes a difference or not. Dont quote me on it but i think he used car polish

desta
NSW, 21 posts
7 Sep 2010 7:02PM
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surfers do it, i have don it to speed boards and surf boards. it recon it helps. at least mentally. jus wishin i could polish my-self sometimes. . . .

sailquik
VIC, 4175 posts
7 Sep 2010 8:11PM
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pacman76 said...

Used to see Mal Wright at sandy point polishing his boards. I think the community is divided about if this makes a difference or not. Dont quote me on it but i think he used car polish


I haven't yet seen Mal polish the bottom of any of his boards, but I have seen him polished a few fins, and yep, we used car polish (cutting polish).

Goo Screw
VIC, 269 posts
7 Sep 2010 8:59PM
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sailquik said...

pacman76 said...

Used to see Mal Wright at sandy point polishing his boards. I think the community is divided about if this makes a difference or not. Dont quote me on it but i think he used car polish


I haven't yet seen Mal polish the bottom of any of his boards, but I have seen him polished a few fins, and yep, we used car polish (cutting polish).


The bottom of that missile xs of his looked pretty polished(or maybe just extra smooth)
I thought ice'ys post covered it as well as I've seen - where did that go???

icesurf
QLD, 113 posts
8 Sep 2010 6:15AM
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I remove my post of info as some geezer was upset about the facts![}:)]

pacman76
QLD, 123 posts
8 Sep 2010 7:21AM
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sailquik said...

pacman76 said...

Used to see Mal Wright at sandy point polishing his boards. I think the community is divided about if this makes a difference or not. Dont quote me on it but i think he used car polish


I haven't yet seen Mal polish the bottom of any of his boards, but I have seen him polished a few fins, and yep, we used car polish (cutting polish).


I am 98% sure we saw him early one morning in the back of his car polishing the bottom of his board, the other 2% is maybe it was his fin in the board. We only saw him from a distance so i cant be 100% sure. We had a discussion with Mathew over whether it makes a difference while i was at Sandy point last time i was there. Maybe its his little secret and he doesnt let you know..... and thats why he is quicker than you haha just kidding

Crash Landing
NSW, 1173 posts
8 Sep 2010 9:10AM
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Slightly off topic, when I used to race Lasers at the British Nationals, the really good guys that got a new hull every year always sanded the shine off the bottom. They did tell my why but this was 12 years ago!

scarrgo
WA, 180 posts
8 Sep 2010 8:01AM
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yeh the reason why sailing boats take the shine off their hulls is sort of why a golf ball is dimpled, if you don't do it air bubbles stick to your hull and slow you down. this doesn't mean you don't want it really smooth though. not sure how well this applies to windsurfing boards though

Ian K
NSW, 2731 posts
8 Sep 2010 1:19PM
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There's always been 2 schools of thought on this one, probably always will be.

Theory says the layer of water closest to the hull is stuck to the hull, and that the ridges left from 600/1200 grit sandpaper don't stick up through the stationary layer and therefore don't affect performance.

Frank Bethwaite, famous author of "High performance sailing" made many experiments of fins and hulls with various finishes. Many experiments where he towed fins and hulls through water carefully measuring the drag. He is well up on the theory but had to conclude the higher the polish the better.

He also noted polished surfaces don't collect grime as easily.

Here's a video of a highly polished bowl rotating. Water passing under a hull is probably equivalent to about 3 turns of the bowl.


Magnus8
QLD, 353 posts
8 Sep 2010 1:45PM
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icesurf said...

I remove my post of info as some geezer was upset about the facts![}:)]


I'd like to see the facts back again! Now I'm upset

choco
SA, 3364 posts
8 Sep 2010 1:23PM
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best way to get a slippery board is to rub the underside of the board with a cake of soap!

sailquik
VIC, 4175 posts
8 Sep 2010 2:01PM
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pacman76 said...

sailquik said...

pacman76 said...

Used to see Mal Wright at sandy point polishing his boards. I think the community is divided about if this makes a difference or not. Dont quote me on it but i think he used car polish


I haven't yet seen Mal polish the bottom of any of his boards, but I have seen him polished a few fins, and yep, we used car polish (cutting polish).


I am 98% sure we saw him early one morning in the back of his car polishing the bottom of his board, the other 2% is maybe it was his fin in the board. We only saw him from a distance so i cant be 100% sure. We had a discussion with Mathew over whether it makes a difference while i was at Sandy point last time i was there. Maybe its his little secret and he doesnt let you know..... and thats why he is quicker than you haha just kidding


It is true that one of the reasons Mal is so fast is that he pays meticulous attention the design and detail of his set up. He could have been sanding the bottom with fine paper. He may well have been polishing it. We have definitely experimented a lot with polishing fins and I think it can make a difference, especially if the foil shape is well designed and optimised (as close to theoretically perfect as possible).

scarrgo
WA, 180 posts
8 Sep 2010 2:54PM
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Ian K said...

There's always been 2 schools of thought on this one, probably always will be.

Theory says the layer of water closest to the hull is stuck to the hull, and that the ridges left from 600/1200 grit sandpaper don't stick up through the stationary layer and therefore don't affect performance.

Frank Bethwaite, famous author of "High performance sailing" made many experiments of fins and hulls with various finishes. Many experiments where he towed fins and hulls through water carefully measuring the drag. He is well up on the theory but had to conclude the higher the polish the better.

He also noted polished surfaces don't collect grime as easily.

Here's a video of a highly polished bowl rotating. Water passing under a hull is probably equivalent to about 3 turns of the bowl.





yes this is true the smoother the finish the better but the initial shinny gloss you get on a brand new gel coat is much slower than a boat sanded with wet and dry 1000< this initial layer wears quickly though and is almost gone after a couple of months but for the top sailors that get brand new boats all the time they need to get rid of this finish faster

desta
NSW, 21 posts
8 Sep 2010 5:37PM
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choco said...

best way to get a slippery board is to rub the underside of the board with a cake of soap!


im so trying this one

saltiest1
WA, 1987 posts
8 Sep 2010 10:19PM
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desta said...

choco said...

best way to get a slippery board is to rub the underside of the board with a cake of soap!


im so trying this one




use tuna oil. on the return run you go faster for 3 reasons:
1. water is flatter.
2. board is slicker
3. the big grey fish chasing you.

Bonominator
VIC, 5477 posts
9 Sep 2010 2:44PM
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scarrgo said...

Ian K said...

There's always been 2 schools of thought on this one, probably always will be.

Theory says the layer of water closest to the hull is stuck to the hull, and that the ridges left from 600/1200 grit sandpaper don't stick up through the stationary layer and therefore don't affect performance.

Frank Bethwaite, famous author of "High performance sailing" made many experiments of fins and hulls with various finishes. Many experiments where he towed fins and hulls through water carefully measuring the drag. He is well up on the theory but had to conclude the higher the polish the better.

He also noted polished surfaces don't collect grime as easily.

Here's a video of a highly polished bowl rotating. Water passing under a hull is probably equivalent to about 3 turns of the bowl.





yes this is true the smoother the finish the better but the initial shinny gloss you get on a brand new gel coat is much slower than a boat sanded with wet and dry 1000< this initial layer wears quickly though and is almost gone after a couple of months but for the top sailors that get brand new boats all the time they need to get rid of this finish faster


I understand the CA boards use a DuPont Teflon compound coat that doesn't wear off that easily. My pro model has the same shiny bum as the day it arrived and it's 18 months old. We'll see. Wet and dry finishes need constant upkeep to keep the scum out of the grooves, but the speed advantage is well, debatable.

scarrgo
WA, 180 posts
9 Sep 2010 6:29PM
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Bonominator said...

scarrgo said...

Ian K said...

There's always been 2 schools of thought on this one, probably always will be.

Theory says the layer of water closest to the hull is stuck to the hull, and that the ridges left from 600/1200 grit sandpaper don't stick up through the stationary layer and therefore don't affect performance.

Frank Bethwaite, famous author of "High performance sailing" made many experiments of fins and hulls with various finishes. Many experiments where he towed fins and hulls through water carefully measuring the drag. He is well up on the theory but had to conclude the higher the polish the better.

He also noted polished surfaces don't collect grime as easily.

Here's a video of a highly polished bowl rotating. Water passing under a hull is probably equivalent to about 3 turns of the bowl.





yes this is true the smoother the finish the better but the initial shinny gloss you get on a brand new gel coat is much slower than a boat sanded with wet and dry 1000< this initial layer wears quickly though and is almost gone after a couple of months but for the top sailors that get brand new boats all the time they need to get rid of this finish faster


I understand the CA boards use a DuPont Teflon compound coat that doesn't wear off that easily. My pro model has the same shiny bum as the day it arrived and it's 18 months old. We'll see. Wet and dry finishes need constant upkeep to keep the scum out of the grooves, but the speed advantage is well, debatable.


yep fair enough there probably isn't a significant difference when talking about polished or wet and dry surfaces on windsurfing boards besides that the polished one tends to collect less grime but i was answering a question about why the top guys in fiberglass gel coat hull boats wet and dry their boats, trust me on this gel coat wet and dry is way faster than a shinny new gel coat

lelos12345
NSW, 453 posts
10 Sep 2010 8:15AM
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Interesting reading.. thanks I may get chance today to take the speed boards out polished bottoms and spent the arvo doing the fins .. will post gpstc tonite
see how we go !
see ya all @ sandy point

Bonominator
VIC, 5477 posts
10 Sep 2010 9:02AM
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scarrgo said...

Bonominator said...

scarrgo said...

Ian K said...

There's always been 2 schools of thought on this one, probably always will be.

Theory says the layer of water closest to the hull is stuck to the hull, and that the ridges left from 600/1200 grit sandpaper don't stick up through the stationary layer and therefore don't affect performance.

Frank Bethwaite, famous author of "High performance sailing" made many experiments of fins and hulls with various finishes. Many experiments where he towed fins and hulls through water carefully measuring the drag. He is well up on the theory but had to conclude the higher the polish the better.

He also noted polished surfaces don't collect grime as easily.

Here's a video of a highly polished bowl rotating. Water passing under a hull is probably equivalent to about 3 turns of the bowl.





yes this is true the smoother the finish the better but the initial shinny gloss you get on a brand new gel coat is much slower than a boat sanded with wet and dry 1000< this initial layer wears quickly though and is almost gone after a couple of months but for the top sailors that get brand new boats all the time they need to get rid of this finish faster


I understand the CA boards use a DuPont Teflon compound coat that doesn't wear off that easily. My pro model has the same shiny bum as the day it arrived and it's 18 months old. We'll see. Wet and dry finishes need constant upkeep to keep the scum out of the grooves, but the speed advantage is well, debatable.


yep fair enough there probably isn't a significant difference when talking about polished or wet and dry surfaces on windsurfing boards besides that the polished one tends to collect less grime but i was answering a question about why the top guys in fiberglass gel coat hull boats wet and dry their boats, trust me on this gel coat wet and dry is way faster than a shinny new gel coat


Yeh I know. Depends on the quality of the gel coat no doubt. If it's got something slightly hydrophobic in it then it's going to outperform dirty wet n dry any day.

lelos12345
NSW, 453 posts
10 Sep 2010 9:47PM
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got a PB today and the board felt real nice so i'm happy to polish

jasonc
WA, 41 posts
10 Sep 2010 11:39PM
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i think polishing the underside of your board will make very little difference, in fact if you could somehow recreate the same speed run twice with all the other variables exactly the same i think the difference would be points of a knot so put it into a practicle sense would make absolutely no difference. also i dont think yacht theory can be crossed over into windsurfer theory(in this topic) because as a yacht displaces over the water, a thin film of water sticks to the hull which creates a water on water sliding action which reduces drag dramaticaly this is why yachties dont want a smooth hull and its the same reason swimmers use the suits with the rough shark skin stuff on them to encourage the film of water to stick however when windsurfers move through the water they are planing which means its always air, water, air ,water as the board passes over chop so any film of water that is created is destroyed by the air passing over the board so the fastest finish in my oppinion would be the most polished one but it doesn't really matter really because it wont make much difference anyway. factors that make the most difference are your technique,the conditions ,your tuning(sail,fin,harness lines etc)

just my thoughts, might not be completely correct

Bonominator
VIC, 5477 posts
11 Sep 2010 10:07AM
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jasonc said...

i think polishing the underside of your board will make very little difference, in fact if you could somehow recreate the same speed run twice with all the other variables exactly the same i think the difference would be points of a knot so put it into a practicle sense would make absolutely no difference. also i dont think yacht theory can be crossed over into windsurfer theory(in this topic) because as a yacht displaces over the water, a thin film of water sticks to the hull which creates a water on water sliding action which reduces drag dramaticaly this is why yachties dont want a smooth hull and its the same reason swimmers use the suits with the rough shark skin stuff on them to encourage the film of water to stick however when windsurfers move through the water they are planing which means its always air, water, air ,water as the board passes over chop so any film of water that is created is destroyed by the air passing over the board so the fastest finish in my oppinion would be the most polished one but it doesn't really matter really because it wont make much difference anyway. factors that make the most difference are your technique,the conditions ,your tuning(sail,fin,harness lines etc)

just my thoughts, might not be completely correct


Your bang on. Technique, fitness and correct equipment selection are much greater factors in overall speed. We're really just talking about that last 5% of potential speed that you'll only achieve if you keep your gear in top shape. You know, polish your fins and board, tune your sail, play with mast, boom and harness position etc until everything just hums. Being a gorilla also helps when it's windy!

kato
VIC, 2327 posts
11 Sep 2010 11:49AM
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Select to expand quote
[quote
Your bang on. Technique, fitness and correct equipment selection are much greater factors in overall speed. We're really just talking about that last 5% of potential speed that you'll only achieve if you keep your gear in top shape. You know, polish your fins and board, tune your sail, play with mast, boom and harness position etc until everything just hums. Being a gorilla also helps when it's windy!


Where do you get a Gorilla from

icesurf
QLD, 113 posts
11 Sep 2010 12:38PM
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Bonominator said...

Being a gorilla also helps when it's windy!



Must be the amount of hair Gorillas have on them,
More hair on them the least friction-faster they go regardless of equipment.


Since I do not have Gorilla status, I will have to rely on that 5% factor

remo81
QLD, 678 posts
11 Sep 2010 1:34PM
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Why not paint the bottom of your board with egg whites and let it dry in the sun. Then whola, you have a self polishing copolymer. All the yachties in the 70's used this one before the rule was brought in that no sacrifical coatings were to be used.

The only problem with the egg white is it use to were off by half way through the first race any way.

I'm still going to have a go at it one day at a speed bank.

scarrgo
WA, 180 posts
11 Sep 2010 11:38AM
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yep definitely i would be much more inclined to refine my technique and gear performance but hey we all need something to do when we're bored and there's no wind

jasonc
WA, 41 posts
11 Sep 2010 1:54PM
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i think i'd be a bit buggered if i ever went speedsailing because im just 63kls and yet i'm 188cm tall, i think thats why i do waves mostly

AUS4
NSW, 945 posts
11 Sep 2010 7:05PM
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wet and dry sand paper 1000 - 1200 grit is the go, polishing will cause the water to stick to the bottom of the board. And that is a proven fact.



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"polishing bottom of boards ?" started by lelos12345