Want more speed?...this ones easy & real

[burroak]

Re: Want more speed?...this ones easy & real

This may be too esoteric but here it is:

Sea-Slide is a urethane-based marine overcoat that uses a unique, bonded inter-polymer complex to bind water to the hull. This layer of water reduces friction between the hull and the surrounding water. Because this durable drag reducing overcoat traps a thin layer of water next to your hull's surface, the power required to move through the water is greatly reduced.

Less resistance means less hydrodynamic drag, resulting in less turbulence and better speed and acceleration. In simpler terms, the boat?s hull becomes extra slippery when wet, allowing it to slide more easily through the surrounding water.

Racers have known that hydrophobic coatings, which are coatings that repel water because they contain silicone or wax, are not effective because they can actually produce greater drag in spite of their smoothness. Sea-Slide coating contains neither silicone nor wax and is ?hydrophilic? or water-loving, and forms a water-to-water interface, rather than hull-to-water. For power-driven boats, a lower co-efficient of friction means increased speed, or lower rpm?s to attain the same speed. For sailboats, the reduced drag produces higher speeds in lighter winds.

 

[Bigprairie1]

Re: Want more speed?...this ones easy & real

Well this makes reasonable sense to me thus far and I get the reduced coefficient of friction bit.
When I first put this thread in here it was based on simply waxing my hull and voila'...I got a couple extra mph out of the boat. If there is/was something else contributing to this....I'm ok with it. Apparently it didn't hurt the top speed at all....so there may be more science to go on this.
Very good feedback on this topic at this point for sure.

 

[QuadManiac]

Re: Want more speed?...this ones easy & real

Any engineer worth his salt will know that the issue here is whether you are getting laminar or turbulent flow across the wetted surface.

Which one wax creates is a mystery to me, lol... Guess I'm not worth my salt. I'll have to Google it.

Here's an interesting article though, for those who care:

http://www.hydeoutdoors.com/boats/randd/

And another good one:

http://old.cruisingworld.com/grimes.htm

 

[kmurray802]

Re: Want more speed?...this ones easy & real

This may be too esoteric but here it is:

Sea-Slide is a urethane-based marine overcoat that uses a unique, bonded inter-polymer complex to bind water to the hull. This layer of water reduces friction between the hull and the surrounding water. Because this durable drag reducing overcoat traps a thin layer of water next to your hull's surface, the power required to move through the water is greatly reduced.

Less resistance means less hydrodynamic drag, resulting in less turbulence and better speed and acceleration. In simpler terms, the boat?s hull becomes extra slippery when wet, allowing it to slide more easily through the surrounding water.

Racers have known that hydrophobic coatings, which are coatings that repel water because they contain silicone or wax, are not effective because they can actually produce greater drag in spite of their smoothness. Sea-Slide coating contains neither silicone nor wax and is ?hydrophilic? or water-loving, and forms a water-to-water interface, rather than hull-to-water. For power-driven boats, a lower co-efficient of friction means increased speed, or lower rpm?s to attain the same speed. For sailboats, the reduced drag produces higher speeds in lighter winds.

Ya thats what I was going to say,but my spell-check's not working!

 

[Bob_VT]

Re: Want more speed?...this ones easy & real

But then you can look at (or feel) a fish and note that when rubbed one direction they feel smooth and when rubbed toward the head the scales bite you. This creates tiny bubbles around the fish which breaks the surface tension. A lake with slight surface ripples will allow faster speeds than one that's glass smooth. Less surface contact the faster you go. That's my story and I'm stickin' to it.

Maybe we should try to wax a fish...... and get the best of all worlds......

 

[Dhadley]

Re: Want more speed?...this ones easy & real

Any time I wanted any of my boats to go faster I simply did whatever it takes to get more hull out of the water (reduce the wetted surface). Once the hull is in the air it doesn't seem to matter if it's waxed or not.........

 

[QuadManiac]

Re: Want more speed?...this ones easy & real

It's when you're just standing on your prop that it gets real hairy!

 

[Scaaty]

Re: Want more speed?...this ones easy & real

It's when you're just standing on your prop that it gets real hairy!

Come'on..thats when its fun

 

[Sorrento 25]

Re: Want more speed?...this ones easy & real

This quote from the Cruising World link makes good sense to me:

Beading vs. Wetting--Any discussion of fast bottom surfaces eventually leads to the question of whether water should bead up on a hull or "wet" the hull so that it flows off in a sheet. "Beading has no relevance," says Kirkman. "It's a function of the surface tensions of the water and hull surfaces, and nobody has been able to explain to me how it has any relation to skin-friction drag underwater."

Even so, both Pedrick and Kirkman suggest that waxes are not a good idea because they seem to attract and/or react with contaminants in the water and can be hard to get as smooth as a finely wet-sanded surface.

 

[troypolla]

Re: Want more speed?...this ones easy & real

I agree with you guys. No wax on the bottom. Maybe on the sides and back.

 

[Bigprairie1]

Re: Want more speed?...this ones easy & real

...well a continuing conundrum. That does it...I'm going to get my wife to pick up 4-5 cans of PAM and I'll give that a try......couldn't hurt?

 

[luckyinkentucky]

Re: Want more speed?...this ones easy & real

I don't buy into it. My boat runs differently on the same lake under similar conditions all the time. For instance, if the temperature is in the mid 80's and less humid I get a few mph on my top end. If it's in the upper 90's with a heat index of 110 my boat loses 3 or 4 mph. Waxing has nothing to do with it. The wax is lost within the first 5 minutes of being in the water when it's below the water line.

 

[QuadManiac]

Re: Want more speed?...this ones easy & real

Always wondered: if you were to put a bunch of small aeration holes starting along the bottom near the front edge of the wetted surface while on plane, and pump air thru them... air certainly has less viscous friction than water... now only if you can deal with prop cavitation/ventilation from it.

Hmmm.

 

[kenmyfam]

Re: Want more speed?...this ones easy & real

This is too much for me.... and I am an engineer.
My hull has been waxed and not waxed. Appreciable difference = None.
Conclusion.
The green stuff that grows on the bottom of my hull appears to grow a little less quickly when first waxed but the power washer takes pretty good care of removing it anyway !!!!

 

[cincy_cosmo]

Re: Want more speed?...this ones easy & real

Even though I'm a total newbie, I guess I can weigh in on this with several confusing facts (and assuming that air flow and water flow are similar things):

Golf balls have dimples to achieve less resistance in flight.

NASCAR flirted briefly and somewhat successfully with vinyl roofs in the 60's to lower air resistance. The vinyl roof idea was outlawed later as the adhesive was letting go of the sheets and presented a potential hazard.

finally,

The Navy made the news a couple of years ago as it was experimenting with cavitation drives on torpedoes, ie, using jets to create air bubbles at the leading edge of a torpedo so it would move faster in the water.

Soooooo. I guess I am going to make a wild, semi-scientific guess here and say that rough surfaces create some form of cavitation and make the surface-to-water areas have less friction. Unlike props, hull cavitation would be good. If you carry that out further, you could say that a pad area on the stern of a boat that has a air-hockey like surface with compressed air causing consistent bubbles would be the ultimate in fast (although the trailing bubbles would cause the prop to cavitate prematurely so it would have to be a jet boat with carefully placed inlets). A dimpled hull next fastest, a dirty hull next, and a smooth waxed hull, well, somewhere slower.

 

[Bigprairie1]

Re: Want more speed?...this ones easy & real

Air bubble separation?...I'll buy that. If you can keep the hull and the water seperated all together that would certainly reduce friction. Not all unlike getting the boat out of the water like a hydroplane (?...ie: on skis).
At the very least I will say that waxing the bottom of the boat certainly did not slow it down. As to where the extra couple of mph came from...well there have been some reasonably scientific hypotheses put in some of these threads as to why. I'll buy it......now what about that PAM experiment?....anyone?

 

[ddennis]

Re: Want more speed?...this ones easy & real

Even though I'm a total newbie, I guess I can weigh in on this with several confusing facts (and assuming that air flow and water flow are similar things):

Golf balls have dimples to achieve less resistance in flight.

NASCAR flirted briefly and somewhat successfully with vinyl roofs in the 60's to lower air resistance. The vinyl roof idea was outlawed later as the adhesive was letting go of the sheets and presented a potential hazard.

finally,

The Navy made the news a couple of years ago as it was experimenting with cavitation drives on torpedoes, ie, using jets to create air bubbles at the leading edge of a torpedo so it would move faster in the water.

Soooooo. I guess I am going to make a wild, semi-scientific guess here and say that rough surfaces create some form of cavitation and make the surface-to-water areas have less friction. Unlike props, hull cavitation would be good. If you carry that out further, you could say that a pad area on the stern of a boat that has a air-hockey like surface with compressed air causing consistent bubbles would be the ultimate in fast (although the trailing bubbles would cause the prop to cavitate prematurely so it would have to be a jet boat with carefully placed inlets). A dimpled hull next fastest, a dirty hull next, and a smooth waxed hull, well, somewhere slower.

Russia also developed a torpedo that generated a "bubble" around the torpedo body. According to US sources it was pretty much the fastest torpedo they had ever seen and was nearly unstoppable due to its speed!

 

[cincy_cosmo]

Re: Want more speed?...this ones easy & real

Russia also developed a torpedo that generated a "bubble" around the torpedo body. According to US sources it was pretty much the fastest torpedo they had ever seen and was nearly unstoppable due to its speed!

Yep...the US Navy cavitation is a result of that. I don't remember what speeds they were making with the torpedoes, but it was well in 3 digits (mph). Popular Mechanics later ran an a fantasty-based-on-reality article with a hypothesis of a under sea transport going as fast as an airplane.

If it works for subs, it would have to work the single surface of a hull.

 

[chaparral442]

Re: Want more speed?...this ones easy & real

This may be too esoteric but here it is:

Sea-Slide is a urethane-based marine overcoat that uses a unique, bonded inter-polymer complex to bind water to the hull. This layer of water reduces friction between the hull and the surrounding water. Because this durable drag reducing overcoat traps a thin layer of water next to your hull's surface, the power required to move through the water is greatly reduced.

Less resistance means less hydrodynamic drag, resulting in less turbulence and better speed and acceleration. In simpler terms, the boat?s hull becomes extra slippery when wet, allowing it to slide more easily through the surrounding water.

Racers have known that hydrophobic coatings, which are coatings that repel water because they contain silicone or wax, are not effective because they can actually produce greater drag in spite of their smoothness. Sea-Slide coating contains neither silicone nor wax and is ?hydrophilic? or water-loving, and forms a water-to-water interface, rather than hull-to-water. For power-driven boats, a lower co-efficient of friction means increased speed, or lower rpm?s to attain the same speed. For sailboats, the reduced drag produces higher speeds in lighter winds.

Any one ever try this stuff??????

 

[OMCboater]

Re: Want more speed?...this ones easy & real

Golf balls have dimples to achieve less resistance in flight.

something about this did not sound quite right to me so I looked it up...

http://math.ucr.edu/home/baez/physics/General/golf.html

I think comparing the golf balls vs waxing hull is not a valid comparison as the dimples do increase drag (according to this article)

Here is a real world comparison I have found. I recently started using Rain-x on my vehicle windshields (via the windshield washer fluid) and have noticed that the water streams off the swept area of the windshield much better with the rainx than without. There is a clearly defined area where the windshield wipers have polished the rainx into the windshield and in this area the water just clears right off. Outside the swept area the water 'sticks' to the windshield.

Now, this may actually support the 'no wax is best' theory as there is the contention that having water stick to your hull allows the hull to slip through the water more fluidly. I guess the theory is that water/water friction will always be les than water/waxed hull. When comparing waxed hull vs non, you are actually comparing waxed hull/water vs water stuck to non smooth hull/water?