Top Speed

[shenders]

I don’t know about this dimple stuff David... I did put dimples on a bottom of one of our hydro's
one time by accident.. I resurfaced the last 36’’ and sprayed the bottom with a good varnish..
After cleaning the gun I turn to look at my great new bottom just to see all these damn little holes
forming up.. To say the least I was ticked.. I let it all dry and was going to re-do it but we had a
race coming up so I just left it alone.. That boat ran better than ever and seemed to brake lose on
acceleration better.. Never did fix it.
Stan

[David Weaver]

Sam,

You are probably right. It may not add to top speed. But it seems that it could improve acceleration by "freeing-up" the back end a little. And it may improve handling.

Besides Region 4's most adventurous family considered this. The Augustine clan considered making a hydro with a completely dimpled-bottom, something similar to an air-hockey table. But they we worried that when it got to the turn that it would continue go straight down the course with boat in a side-ways position.

The dimpling of the golf ball is more involved than just trying to creat maximum speed. It is always nice when the ball travels in the intended direction or with the intended "action" . The knuckle-ball does work to great effect in golf. The dimpling also helps to stop the ball on the green by generating the correct spin.

Golf is a waste of time, but I cannot waste all my time boat racing!!

[Jeff Akers]

Beeing a watersports kinda guy I've done some Wakeboarding/ wakeskating and noticed a few years ago some wakeboard manufactures trying dimples of differant shapes and sizes. I personally couldnt tell the diferance from one with or without but I'm no expert. It seems that industry has gone away from dimpleing though. Here's a little info I found on a wakeboard site.

Dimples, also referred to as phasers, speed bumps, etc., are designed to break up laminar flow, or downward suction on the board from the water's surface. If you think of a dinner plate being set on a wet table, and the suction that is created, the principle is the same. The dimples break up the suction and, in theory, accelerate the board. In reality this does very little to effect performance positively or negatively. It is technology that was borrowed from the surfing industry, which largely dropped the concept about 20 years ago.


Yea we are talking about higher speeds with boats but same basic Idea right?

[David Weaver]

Would this concept be similar to running on glass smooth water? Years ago we used to teast at Lake Alfred on the pretty water that had not a ripple on it. You could not get a 250 or 350 hydro to run for $^#t. The boat would just suck down to the surface of the water. This year I tested a 250 runabout on glass smooth water. Same thing, the boat would not release from the surface tension. Would the dimpling help break free of the surface tension by allowing air to pass under the back of the boat in a manner that creates some turbulence?

[denny henderson]

Cuz,
Was that the same boat that had the paint thinner can fuel tank?

[Jeff Akers]

Would this concept be similar to running on glass smooth water? Years ago we used to teast at Lake Alfred on the pretty water that had not a ripple on it. You could not get a 250 or 350 hydro to run for $^#t. The boat would just suck down to the surface of the water. This year I tested a 250 runabout on glass smooth water. Same thing, the boat would not release from the surface tension. Would the dimpling help break free of the surface tension by allowing air to pass under the back of the boat in a manner that creates some turbulence?

It would make sence that it would work on "like glass" water just to the point of geting it unstuck and then have little or no efect in "normal racing conditions" It may allso efect one type of boat/class and or setup more than another?

Entrop got around it by just flying the hole boat "propriding"

[Sunburnt]

In the early 60's McCulloch built a factory pleasure hydro based on the fantasy hull, but they added dimples. I'm sure the result was neglegable or even measurable but at least they made the attempt. They persued all options to get the boat to go 50 with a single 75.

here is the link to pictures from a previous thread.
http://www.boatracingfacts.com/forum...ead.php?t=1787



Jeff

[JohnsonM50]

I heard it called that by a jersey skiff guy but on kneeldowns Ive only seen sanding. On fibreglass / gelcoat Ive heard of glass beading for the effect. Ive not played golf yet but as for flight I saw courtesy of History channel where an experimental aircraft was set up with pores and an active vacuum system to change the resistance for speed,

[Mark75H]

In the early 60's McCulloch built a factory pleasure hydro based on the fantasy hull, but they added dimples.

I'm not 100% certain that was done by the factory

[59powercat1400]

I am. I have a guy in Minneapolis that was at hydrocraft when these were being tested. he told me about the dimples long before I had this boat. he got to test these boats and was sent out to see if they could break em. the only problem they had was they bent the tubes on the first few lifts. they made them out of thicker wall tubing and it cured the problem. dick