Micron 66 bottom paint

[conehead39]

We use a lot of fuel in one year on CONTAGIOUS. The decrease in drag of Micron 66 pays for itself numerous times over.
The Islamorada Charter Fleet uses Micron 66.
So do we.It takes about 5 quarts to clean and re-coat it. Generally most charter boats every Sept -Oct .

[Cattywampus]

Do you know how the AHR (average hull roughness) of a clean, unpainted bottom would compare to a bottom painted with Micron 66?

Jim

[conehead39]

Ask Brian Cooke in engineering for AHR on clean bottom.

We barrier coated+micron 66 before the boat went in the water,fall 2005.
We have just cleaned it and re-coated about every year or touch up when hauled out.

Harry BROF. ran clean for several years,trailering.
He moved to Pensacola and barrier coated/micron 66.
His data showed very little difference clean vs micron 66.

If you want it real slick,then paint it with INTERSLEEK .like British Navy and oil tankers do.
Good luck on buying it.
http://www3.marinelink.com/pda/PdaStory ... yID=216641

[Harry Brosofsky]

I lost about 1 knot when I painted the bottom. Fuel economy difference was less than 5%.

Harry

[TowBoatUS]

Okay, I’ll bite. We all know that a dirty bottom has more drag, but do we have any imperial data, like coefficient of friction for the various products. I’ve seen the claims and know the blow boat guys who race are fanatics about keeping the bottom slick….. However, are we talking real measurable numbers or a theoretical difference? Micron 66 is a good paint but is it worth the cost difference when it comes to fuel consumption????

[conehead39]

i think Harry answered it. < 5% reduction.

Now this below does NOT have any mumbo jumbo computer data.
My son's boat is parked at the dock. You can jump in the water at low tide.
All three boats are in the water,side by side. The 330TE is in the middle.
The other two boats,Grady white 31,old inboard??, both have hard non self polishing cheapo bottom paint.

You can run your finger tips over ALL three of the boats bottom paint (wet).
The Micron 66 has less surface drag. It is as simple as a good car body repair man using his finger tips checking for smoothness.

http://www.jamestowndistributors.com/us ... &page=GRID
SCROLL TO BOTTOM OF THE PAGE. It will discuss ALL the types of bottom paints,(Pros + Cons)


No formula needed

DRAG = coefficient of drag Cd x 1/2 rho(density of the fluid) x v squared x surface area,

D= Cd(1/2 rho (vxv) (Surface Area).

Check your Fluid Dynamics books and or Aerodynamics for Military Aviators,author Prof Harry Hurt, Univ So CA..
same guy did the LA motorcycle accident study, he told me aerodynamics were boring. I took his motorcycle course
part of USAF safety officers/accident investigation school curriculum. Nov, Dec 1978.A real down to earth guy,no fancy words.

edit ...
see link it is the same as I posted ,just arranged slightly different. doesn't matter they are all multiplied together .

http://en.wikipedia.org/wiki/Drag_equation

[conehead39]

Let's say that Micron 66 is only a 2% reduction in drag.
Lets say Tow Boat US in Clearwater average burn is 40 gal of fuel per day/boat.
You are on the water 330 days a year,(we are on the water less now ~ 270 days/year), but we average 50-60 gal /day.
Your 330 days x 40 gal/day =13,200 gal/year x fuel average price $3 /gal.
13,200 gal x $3= $39,600 per year.
Two percent .02 x $39,600= $792.
Micron 66 we can buy for $200 /gal.
It only takes one gal to coat a 270 or less in size.

$792-$200= $592 you save/ year. That's not counting Cheapo bottom paint at $80.gal you have to buy.

What if it was a 4% drag reduction, then $792 x 2 = $1584-$200(micron 66)=$1384.

As they say in the south,THAT AIN"T EXACTLY CHICKEN FEED.

Now how many boats do you have???

[Harry Brosofsky]

The benefit of Micron 66 is really that it is an SPC paint. It works like a very slow disolving Alka Seltzer tablet. Regular ablative paints wear off quickly at higher speeds (erosion). Hard paints leach out the chemicals and then need to be stripped. SPCs wear off by chemical reaction with the water, not by friction...no build up, no fast waer off. They can be hauled and don't need to be stripped and repainted. When you use Micron 66, it is best to lay down a contrast coat, then 2 coats of the desired color. When you see the contrast coat, haul the boat, power wash, hit with a 3M scrunge scrubber, let dry and repaint. No hard sanding. FYI, mine wears out almost perfectly evenly, with no fast spots due to high speed erosion. In two years in the water (with 4 months on the hard while I was in Iraq), I had no shell fouling, no grass, and only a very slight slime growth that washes off as soon as the boat hits speed. In the northeast, it should last even longer.

Harry

[v70catboat]

I understand that you should not wax a bottom because it actually makes you go slower.

So why is it that the roughness of paint gives you more drag?

[conehead39]

Same reason that anti skid paint or coating causes more drag.