Boat Bottom

[eekern]

google these terms and you'll get facts about the science behind it: Cassie state, Wenzel state, contact angle hysteresis

 

[David Santistevan]

I always use the sex wax, but not on the boats ! I have found that sanding the bottom has a pretty significant impact on the performance of the boats. I block all of my riding surfaces with 400 dry, you are just trying to break the water tension on them.

D

 

[Lennard Cuenco]

i agree...the rougher the better, you dont want anything smooth/glassy facing the water

i finish with something to break surface tension

I always use the sex wax, but not on the boats ! I have found that sanding the bottom has a pretty significant impact on the performance of the boats. I block all of my riding surfaces with 400 dry, you are just trying to break the water tension on them.

D

 

[glenng]

Leonard, you did not say what you finish with to "break surface tension". Science be damned- when those people do not have the answers they will "extrapolate" something. Look that up in your dictionary- they take a guess. They have been pushing global warming for years- how many have had lower than normal heating bills this winter? I will not take 400 grit wet or dry to a nice clear coat on a hydroplane as little of it is in the water much anyway. Sanding with 800-1200 grit will make it smoother than the original paint. I do not run boats much anymore so if they are lucky they will get a coat of Teflon wax every other year.

 

[Beau Parsons]

I have head that there was a guy that after every race applied his secret wax and had the fastest boats on the circuit. So I understand the theory of sanding but if this guy has the fastest boats on race day it must work right?

Beau

 

[eekern]

I love it when people poopoo global warming when we have a cold winter........ its the same logic people use when they say they will never invest in stocks again because the dow jones was in the tank a few years back. Its not about one winter, its about the TREND that the average GLOBAL temperature goes up nearly every year since the industrial revolution. Sometimes people have a hard time seeing beyond their own back window.....

Now back on topic,

go to you tube and search "superhydrophobic teflon surface".....its a Teflon surface that has been sanded to break surface tension, pretty cool

 

[Lennard Cuenco]

hey glenn..

jack garcia had me finish blueprinting sponsons by roughing up the running surfaces with 60 grit

(thats right...rocks on paper)

Leonard, you did not say what you finish with to "break surface tension". Science be damned- when those people do not have the answers they will "extrapolate" something. Look that up in your dictionary- they take a guess. They have been pushing global warming for years- how many have had lower than normal heating bills this winter? I will not take 400 grit wet or dry to a nice clear coat on a hydroplane as little of it is in the water much anyway. Sanding with 800-1200 grit will make it smoother than the original paint. I do not run boats much anymore so if they are lucky they will get a coat of Teflon wax every other year.

 

[SayMikey]

Wax on Wax off or something like that. Only shine is in the jar

 

[glenng]

Leonard, thanks for your reply. Was Jack Garcia a tunnel boat guy? I can understand a bit if the boat had wet surfaces in the water at all times(like a tunnel hull or deep V but do not understand why this would apply to hydroplanes as well. I know what 60 grit is- rocks on paper like you said. You still fail to mention what treatment you apply.

 

[glenng]

O.K. Eric, since you are 37 and all wise and all knowing I started machining Teflon when you were 5 years old. I know the properties of materials better than you probably ever will. The u tube vid just showed nothing sticks to Teflon. Do what you want- rough it up-treat it with Teflon or file it wherever you would like,

 

[eekern]

All knowing? All wise? That's the great oz, perhaps you have heard of him, you were probably my age when that movie came out.

The video shows a comparison of the breaking of surface tension between Teflon sanded with 240 grit and smooth. Did you read the description.? Did you watch the whole video?

As I stated above, read about Cassie state, Wenzel state and contact angle hysteresis and you will understand why water sticks less to a properly roughed hydrophobic eg. 240-320 grit roughed painted surface, versus a smooth one.

As for me, I'm going to go watch grumpy old men and laugh my self to sleep

Best regards

 

[glenng]

Go laugh yourself to sleep Eric, I prefer not to sand the clear coats off the bottom of my hydros and your opinion does not impress me. I watched the whole video and was not AMAZED. You talk about cutting thru the clear coat that protects the hull but offer no proof that the rough sanding offers any Increase in speed. It just has to be treated with Teflon afterwards.

 

[Mike Larson]

I wanted to be... the first guy to skin hydro running surfaces, or maybe a tunnel with dimpled material per a golf ball.. who's actually tried that?... ski, and water break technology, sorta took that off the plate.... idk... i sand my stuff to 400 if it touches water....

 

[Grimracer]

Scuff with 320 scotch-brite.. (after blueprinting)

Grim

 

[anthony_marquart]

I sand mine to 400,.. this makes a big difference on my sport hydro

 

[eekern]

google these terms and you'll get facts about the science behind it: Cassie state, Wenzel state, contact angle hysteresis

I never expressed my opinion. I mentioned some key words/phrases related to the proven science(facts) related to the topic. I was promptly flamed for it.

And yes, there are things that stick to Teflon.

 

[Duck899]

Post number 3 was more fun

 

[glenng]

Yes post three was more fun(at Phil's expense). Eric you can take off the fire suit now. Correct me if I'm wrong- Rob won the 2013 NAMBA Nats. In the 1/8 scale class without sanding his sponsons. I've talked to a friend who has won many races without sanding running surfaces. Another that did sand the sponsons told me he noticed no difference. It's just a hobby do what you want with your boats and enjoy.

 

[Grimracer]

The main reason I scuff is some time ago now I setup a B mono.. the boat was fast.. about 40mph (this was some time ago..lol).. I scuffed and had to retune the boat.. (44mph). I was blown away. I did this test back to back one day at the pond one day.. Now.. I scuff EVERYTHING.. even if some don’t respond as well as others to it.

I also know of at least one other proven incident scuffing a bottom of a Tunnel boat. The boat went on to set a record that still holds today.

Grim

 

[anthony_marquart]

Of course "to each their own",. But I can show data,.. that proves a polished surface creates more drag on the water than one with about a 400 grit scuff. It's about a boundary layer that is created,.. I study surface energy at work.

On my sport hydro that had curved sponson running surfaces, I ran it with polished bottoms.. I could not get the hop out of the corners. tried all kinds of things. I went home and scuffed the running surfaces and dihedral surfaces,.. came back the next day and it was gone. and was gone ever after.. I think that the left sponson was sticking in the corner and making the transom lift..