Underwater surface finish
 

I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo’s
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

Bruce in Bangkok wrote:
I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo’s
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Take a look at:

http://www.sharkskincoating.com/newsE.asp?newsid=242

Brian C

Underwater surface finish
 

Bruce in Bangkok wrote:
I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo's
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

The skin from a couple of Great Whites would just about cover my underwater
hull. Do you know anybody who could sell them to me?

Dennis.

Underwater surface finish
 

On Sat, 16 Aug 2008 11:51:13 +0100, "Dennis Pogson"
wrote:

Bruce in Bangkok wrote:
I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo's
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

The skin from a couple of Great Whites would just about cover my underwater
hull. Do you know anybody who could sell them to me?

Dennis.


Probably best if you get your own.
Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

Forget it, Bruce. It would never work on a boat like yours that stays tied
to a dock for thirty years.

Wilbur Hubbard

"Bruce in Bangkok" wrote in message
...

I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo's
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

Give it a few years. U. Florida has been studying shark and porpoise skin
for some time trying to produce a low friction non-depleting non-toxic
anti-fouling coating for the Navy. Last I heard they were in full scale
testing.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Bruce in Bangkok" wrote in message
...

I've been watching the olympic swimming and notice that nearly all of
the swimmers wear the new performance swimming suits. I did a bit of
research on the web and came up with the following quote from Speedo:

The LZR-Race suits promise to have 5 percent less drag than Speedo's
previous best FASTSKIN PRO suits that have helped break world records
in the past year. Speedo also claims swimmers will have 5% better
oxygen intake efficiency thanks to stronger core compression section
along the abdomen area.

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

On Sat, 16 Aug 2008 12:14:57 -0400, "Glenn Ashmore"
wrote:

Give it a few years. U. Florida has been studying shark and porpoise skin
for some time trying to produce a low friction non-depleting non-toxic
anti-fouling coating for the Navy. Last I heard they were in full scale
testing.

I was under the impression that anti fouling paint, or copper sheets
for that matter, work only because they are toxic.

Casady

Underwater surface finish
 

On Aug 16, 11:46*am, (Richard Casady)
wrote:
On Sat, 16 Aug 2008 12:14:57 -0400, "Glenn Ashmore"
wrote:

Give it a few years. *U. Florida has been studying shark and porpoise skin
for some time trying to produce a low friction non-depleting non-toxic
anti-fouling coating for the Navy. * Last I heard they were in full scale
testing.

I was under the impression that anti fouling paint, or copper sheets
for that matter, work only because they are toxic.

Casady

Thats true, unless you can find a new material that will not allow
anything to stick. Ever see a barney on a shark?

There were some "Snake Skin" coatings that were rolled on in 6 layers.
Once anything stuck the friction would make the paint layer shed. Ok
but major hassel to apply right.

Fred

Underwater surface finish
 

On Sat, 16 Aug 2008 12:38:29 +0700, Bruce in Bangkok
wrote:

...Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok

Slime has been used successfully as a hull coat. It's a consumable
though.
There have been experimental hulls with clse spaced chines - getting
them right is quite a trick.
And finally, there have been air-blown hulls.....

Brian W

Underwater surface finish
 

Give it a few years. U. Florida has been studying shark and porpoise skin
for some time trying to produce a low friction non-depleting non-toxic
anti-fouling coating for the Navy. Last I heard they were in full scale
testing.

I was under the impression that anti fouling paint, or copper sheets
for that matter, work only because they are toxic.


It has something to do with the texture and flexibility. It is apparently a
thick coating that has a microscopic surface pattern that slime spores and
barnacles have a hard time binding to. It also flexes slightly under
varying water pressure so the barnacle cement pops off. A side benefit is
that those little bumps improve laminar flow reducing wetted surface drag.
Sort of like the dimples on a golf ball.
--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com

Underwater surface finish
 

"Glenn Ashmore" writes:

It has something to do with the texture and flexibility. It is apparently a
thick coating that has a microscopic surface pattern that slime spores and
barnacles have a hard time binding to. It also flexes slightly under
varying water pressure so the barnacle cement pops off. A side benefit is
that those little bumps improve laminar flow reducing wetted surface drag.
Sort of like the dimples on a golf ball.

It is the other way around actually. The dimples of golf balls are
there to trip the boundary layer to make sure you get rid of the
laminar boundary layer.

--
Martin Schöön "Problems worthy of attack
show their worth by hitting back."
Piet Hein

Underwater surface finish
 

On Sun, 17 Aug 2008 00:21:36 +0200, (Martin
Schöön) wrote:

"Glenn Ashmore" writes:

It has something to do with the texture and flexibility. It is apparently a
thick coating that has a microscopic surface pattern that slime spores and
barnacles have a hard time binding to. It also flexes slightly under
varying water pressure so the barnacle cement pops off. A side benefit is
that those little bumps improve laminar flow reducing wetted surface drag.
Sort of like the dimples on a golf ball.

It is the other way around actually. The dimples of golf balls are
there to trip the boundary layer to make sure you get rid of the
laminar boundary layer.

This is true.
When you hit a golf ball the loft [slope] of the clubface puts
backspin on the ball. This sucks air off the top and piles it up under
the ball. This pressure difference holds the ball up and makes it fly
farther. The dimples get a better grip on the air, so this Magnus
Effect works better. A smooth ball will go about half as far.

Casady

Underwater surface finish
 

3M product was "riblets", used in Perth. Works and was banned. The
application of a Swedish concoction sloughed-off and left the riblets
clean. Had to be washed off and re-applied every night. Sometimes
America Cup technology does not trickle down. Them's the rules from
'86. Dry sailing is required.

Underwater surface finish
 

On Aug 16, 6:21*pm, (Martin Schöön) wrote:
"Glenn Ashmore" writes:


It is the other way around actually. The dimples of golf balls are
there to trip the boundary layer to make sure you get rid of the
laminar boundary layer.

--
If you google riblets you will find the 3M product as an adhesive application. These were banned by the AC and the accompanying "go-fast" solution. This was in the days of "national origin" of equipment

Underwater surface finish
 

Just reading up on golf ball dimples They evidently create a thin layer of
turbulence that keeps the laminar flow from breaking away longer reducing
the turbulent area behind the ball. Discounting the Magnus effect because
a hull does not (normally) spin, the result is less drag.

That said, it seems to follow that dimples on the mast would hold the air
flow around it further aft reducing the turbulence on the luff of the main.
Probably not much but then the big racers cut their toothbrushes in half...
:-)

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

wrote in message
...
On Aug 16, 6:21 pm, (Martin Schöön) wrote:
"Glenn Ashmore" writes:


It is the other way around actually. The dimples of golf balls are
there to trip the boundary layer to make sure you get rid of the
laminar boundary layer.

--
If you google riblets you will find the 3M product as an adhesive
application. These were banned by the AC and the accompanying "go-fast"
solution. This was in the days of "national origin" of equipment

Underwater surface finish
 

On Sun, 17 Aug 2008 14:50:12 -0400, "Glenn Ashmore"
wrote:

Just reading up on golf ball dimples They evidently create a thin layer of
turbulence that keeps the laminar flow from breaking away longer reducing
the turbulent area behind the ball. Discounting the Magnus effect because
a hull does not (normally) spin, the result is less drag.

That said, it seems to follow that dimples on the mast would hold the air
flow around it further aft reducing the turbulence on the luff of the main.
Probably not much but then the big racers cut their toothbrushes in half...
:-)


The guy in the next slip to me is a serious racer, and pretty
successful at it. He talks about "seconds per mile" and I assume that
if a "golf ball" finnish would actually increase speed he would be
spending every Sunday punching dings in his hull.

Since he isn;t I suspect that dimples probably don;t effect the speed
of a boat hull.

However, boats, particularly submarines, operate in very similar
conditions as a competitive swimmer and if the new suits give them a
5% decrease in drag then why not boats? Or perhaps, why them and not
boats?


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

Bruce in Bangkok wrote in
:

On Sun, 17 Aug 2008 14:50:12 -0400, "Glenn Ashmore"
wrote:

Just reading up on golf ball dimples They evidently create a thin
layer of turbulence that keeps the laminar flow from breaking away
longer reducing the turbulent area behind the ball. Discounting the
Magnus effect because a hull does not (normally) spin, the result is
less drag.

That said, it seems to follow that dimples on the mast would hold the
air flow around it further aft reducing the turbulence on the luff of
the main. Probably not much but then the big racers cut their
toothbrushes in half...
:-)


The guy in the next slip to me is a serious racer, and pretty
successful at it. He talks about "seconds per mile" and I assume that
if a "golf ball" finnish would actually increase speed he would be
spending every Sunday punching dings in his hull.

Since he isn;t I suspect that dimples probably don;t effect the speed
of a boat hull.

However, boats, particularly submarines, operate in very similar
conditions as a competitive swimmer and if the new suits give them a
5% decrease in drag then why not boats? Or perhaps, why them and not
boats?


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)


Do you think the suits came before the subs - or the subs came before the
suits?

Underwater surface finish
 

"Glenn Ashmore" writes:

Just reading up on golf ball dimples They evidently create a thin layer of
turbulence that keeps the laminar flow from breaking away longer reducing
the turbulent area behind the ball. Discounting the Magnus effect because
a hull does not (normally) spin, the result is less drag.

That said, it seems to follow that dimples on the mast would hold the air
flow around it further aft reducing the turbulence on the luff of the main.
Probably not much but then the big racers cut their toothbrushes in half...
:-)

Alu spars for monohulls used (I haven't checked this in a while) to
have a few riblets about one fourth down-stream on each side to trip
the boundary layer to stop von Karman vortices from forming. This reduces
the separation bubble on the suction side of the sail and reduces
the risk of spar oscillation in harbour.

Another approach is of course to make sure the spar contribute
to drive rather than to drag: a rotating wing-shaped spar.

--
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein

Underwater surface finish
 

I’ve been using this technique on my boats bottom for years. The
doubting Thomases in the boat yard assumed that it was because I was
just too bone idle to prepare the surface properly and that my
painting technique was lousy. But I knew better. Still haven’t got it
quite right though, a few more lumps this year and she should go like
greased lightning.

Mike.


I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

Underwater surface finish
 

On Sat, 16 Aug 2008 12:38:29 +0700, in message

Bruce in Bangkok wrote:

I wonder whether this phenomena applies to boats? Should we be
attaching shark skin to our boats?

I have seen the dinghy sailors polishing the underwater surfaces of
their dinghys with 2,000 grit sandpaper and wonder whether this might
actually be the wrong thing to do.

Is there any empirical information regarding the application of this
technology to boats?

The orientation of the surface is very important in determining
whether drag is reduced or increased, thus the effect is much easier
to manage on submerged bodies like sharks or aircraft, rather than
surface craft like sailboats that are subject to varying flow
directions due to wave action, heel angle, etc.

The effect is real. The major problem in application so far has been
that the surfaces are fragile and easily damaged by things like
slings, collision with minor debris, etc. It's not worth it outside
racing, and the RRS prohibit it.

Ryk

Underwater surface finish
 

I dunno bout all dat fancy schmancy stuff what youse guys is huffin' bout,
but its pretty common knowledge that in high speed stuff like the racing pad
on the bottom of a modern bass boat, an ultra smooth waxed finish is not as
fast as a scuffed finish. Of course us psychotic bass boat drivers don't
get much chance to compare around here. One run up the river, and you skip
two or three sandbars giving that pad a nicely scuffed finish. They always
seem to be faster coming back down river. LOL.

Bob La Londe
www.YumaBassMan.com