A Year of Fouling and Half Knot Speed Loss

[Roger Long]

This is what it looks like:

The VC17M paint actually stayed very clean for most of the year. There was no detectable speed loss until about six weeks ago. Once the copper wore out, the water got warmer, and I wasn't underway as much, things started to grow.

Probably 75% of this growth just happened since I arrived back in Maine. Speed under power was down 1/2 knot but we were still making over 6 knots on a broad reach during the last daysail the day before haul out.

 

[Warren Milberg]

....and you think you've got growth....

 

[kloudie1]

Quite a vegetable farm, Roger.. but Warren wins some kind of "grower of the month" award..

 

[rtshinn]

Can I expect that much in fresh water?

 

[redhead78]

Jeez Warren looks like a Chia Pet....how long were u in water , where, and what kind of paint????? Red

 

[Jim Seamans]

Warren, Please tell me, that was not your boat....

 

[JohnS]

Warren, Please tell me, that was not your boat....

Are those BADGERS?!?!

 

[Stu Jackson]

You did that whole trip with a 2 blade prop? Anyone coulda told you you'd never make it.

 

[zeehag]

omg--ye can still see boat hull--your garden is deficient.

 

[Dan Hill]

If I remember right that is #2 prop

 

[TAK]

Warren, please tell me that is not actually your boat and Herring Bay growth. It looks more like some tropical jungle growth. Regards from HHS.

 

[Roger Long]

You did that whole trip with a 2 blade prop?

Sure. Strider bucks into a head sea as well as any trawler yacht. A prop is inherently more efficient the fewer blades it has. As long as you have sufficient clearance, a two blade prop works just fine.

 

[Ron20324]

....and you think you've got growth....

Another Rogain experiment gone a-foul!

 

[anchorclanker]

....and you think you've got growth....

That is nasty

 

[sinnettc]

Can I expect that much in fresh water?

Probably not. I'm in fresh water and the VC17m does a pretty good job. I get a bit of slime and some crusties along where the keel & hull meet, especially on the shady side (go figure) but nothing that doesn't wash off easily.

 

[jibes138]

Sure. Strider bucks into a head sea as well as any trawler yacht. A prop is inherently more efficient the fewer blades it has. As long as you have sufficient clearance, a two blade prop works just fine.

Sorry Roger I can't resist. If this is true then as the number of blades approaches zero will my sailboat plane like a motorboat? :>) What happens when you get below 2?

 

[All U Get]

Does this mean the dock space under the bridge is open? Will it take long (or Long) to scrape it clean? So many questions.
All U Get

 

[Roger Long]

What happens when you get below 2?

There have actually been some experiments, primarily with wind turbines, using a single prop blade and a short stub with a counterweight. Efficient but long. If I were to try this on my boat, the blade would need to be twice as long which would require a rather extreme shaft angle. That would offset any theoretical gains.

It isn't number of blades that is important but blade area. When this is restricted by available space, increasing the number of blades increases the area. Most sailboats have the space available for a prop restricted enough that they do better under power with a 3 blade. The E32 has enough clearance for a 2 blade to work well.

 

[Jimm]

This is what it looks like:
The VC17M paint actually stayed very clean for most of the year. .

CSC Micron66 - two years in the Bay between hauls with a diver to clean in the odd year.

 

[anchorclanker]

While a single blade is scientifically and factually most efficient, the complications have remained difficult to overcome. They have even tried single blade rotors on helicopters.

A 2 blade boat propeller is more efficient, but a 3 blade is quieter and smoother. Its a compromise.