[Kenneth Athans]

Thanks Rob and Bill!

— Due to the tight engine compartment I don’t have a way to measure WOT loaded but it does seem the analog tach
is a bit off. WOT jumps between 3250 and 3350 loaded on my current dash tach setup. The only way I’ll be able to
measure is with some sort of proximity switch connected to a digital gauge to measure unless you know of a better
way.
— Yes, 2001 Albemarle 280 Express
— 4 blade props and ratio is 1.586:1
— I use trim tabs but they don’t seem to help in that RPM range

I haven’t run into Dave Itano or Jeff Muir. Do they operate out of Oahu?

Thanks,
Ken

[Kenneth Athans]

Here are the list of answers to your questions.

A. At what speed RPM & vessel speed does the vessel get up on a clean plane?

2300 rpm @ 12-13kts

B. Does the vessel struggle at all getting up on plane–meaning you have to give it most of all it’s got to get it up on top, and then back off?

Not all…turbos spool right up and black smoke goes away as boat gets up on plane.

C. When getting up on plane, do you see any black smoke?

No

D. Ever verified your tach accuracy–I.E. 3000 on your tach = what real RPM on a strobe?

Tach was 100 rpm lower at the dock at 3300 rpm.

E. What is you WOT RPM on the tach “loaded “as you use the boat.

3300 RPM

F. EXACTLY why were the turbo replaced at such low engine hours?

Turbos were replaced on my boat because the previous owner allowed rags to get into the oil system which blocked oil lines to turbos. Mechanic took the lube
oil cooler out to be cleaned and owner stuffed rags in the lines to prevent dripping and never took them out prior
to the mechanic putting things back together.

I’m looking to get better performance/efficiency in the 8-10kt range because that’s where I spend most of my time trolling. I don’t care about top end speed as I rarely push the boat that fast. Props are stock and 18×18 with
medium cupping.

Yanmars also have a boost compensator adjustment and not sure if that would help my situation along with going to an 18×17 or even 18×16 prop with medium cupping.

Appreciate the advice from all in helping me work through this issue.

[Kenneth Athans]

Thanks, Tony. Here are a few answers below. The rest I’ll observe when I take the boat out later this week.

B. No struggle at all to get up on plane

C. No black smoke at all after getting up on plane…nothing but a nice clean wake.

D. I’ve never verified tach accuracy

F. Turbos were replaced on my boat because the previous owner allowed rags to get into the oil system which
blocked oil lines to turbos. Mechanic took the lube oil cooler out to be cleaned and owner stuffed rags in the lines
to prevent dripping and never took them out prior to the mechanic putting things back together.

[Kenneth Athans]

Attached is a pic of the engine turbos and exhaust elbows minus the new turbo filters I just installed to replace to stock Yanmar filters. My friends boat has only 600 hours and turbos got corroded pretty bad due to the boat not being operated for several years.

I agree with the boat/installation thing and I’m waiting for a call back from Albemarle regarding prop issue to see if they have dealt with this before. I’m ready to replace the props but just want to figure out the best pitch/cupping given the issue.

[Author]

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