Engine Slow = Boat Slow

[Ex-Calif]

We put the boat in the water August 10, just over 7 weeks ago, after having her hauled up for bottom paint and a new prop.

After refloating we saw 5.8 knots @ 2500 RPM.

Two weeks ago I noticed that we were only getting about 2300 RPM at WOT and last week when we went out, only 2100 RPM. Naturally I was concerned - I revved the engine up in neutral and no problem getting 3200 RPM.

I decided that the bottom was fouled and asked the club to pull it and power wash it on monday. This is a nice service for about US$80. They pulled it on Monday.

The club manager called me and said that it was pretty fouled and that he saved a spot for me to look at. You can see the attached growth in just 7 weeks. what you see is already dried and it was actually up to 3/4 inch thick in barnacles and mussels.

I am not a happy camper ;-(

I have not paid the entire bill for the bottom paint and aside from the realtive innefectiveness of the paint he selected, I can already see primer coat in several spots. This is after he told me he had done 4 coats.

Comments are certainly welcome.

[gegroves]

Dan: You might have two problems here: a) the obvious bottom growth which you should make the people redo, and pay for the haulout; and, b) it sounds like your engine fuel filter may be clogged with junk. Usually when the engine rpms start a gradual slow down, along with boat speed, the first place I ceck is the engine fuel filter. Presuming you have a diesel engine, under load it will slow down but may rev up when not under load. Just a thought.

[Ex-Calif]

Thanks Gary - We also took the oportunity to do a regular engine service - oil, oil filter, fuel and air filter, etc...

[Pblais]

Comments are certainly welcome.

You don't normally "save" a section to show later. It becomes like concrete after it is allowed to dry out and difficult to remove. You may have had bottom paint applied but it looks not to be anti fouling paint. This time of year we can grow that much in less than 7 weeks. My paint is now two years old and over the past month the growth is getting bad. It's time to haul and repaint.

You may have lost rpm's from growth on the prop. I'm sure it didn't look much better than the bottom. With enough growth on the prop you at least can eat all the stuffing from the stuffing box, maybe through the shaft out of alignment as well.

[jdoe71]

That amount of bottom growth is going to be some huge drag. You mentioned new prop, they didn't happen to change pitch/diameter did they? Just a thought.

[Alan Wheeler]

What was the Anti-foul coating?
I assume a hard type, which does not tend to be as effective as the soft, but still should be far better than just 7 weeks.
What was on before the new coatings, and how was it prepared before application of the new coating.
Are you sure the waterblast didn't remove the new coat???