What a difference!

[old_navy]

When I bought the boat three years ago the inspecting marina mentioned 'it could use a bottom job' and at the time i didn't realize that meant 'You need this now'. At any rate, Cedar Mills Marina finished the boat last week and I took it out for a shake down cruise; wound up an enjoyable all day event actually! Anyway; I had a bottom job, tune up, prop replacement, trim indicator not working fixed, temp gauge fixed, etc, etc. I went from a max 4200 rpm / 15knots to:

max 4400 rpm and 27knots (30mph)!

I still have a trim issue as the boat lays over to starboard as the rpm goes up and I cannot trim it out. I think one of the trim tabs may be stuck and will investigate on next outing.

http://www.old-navy-guy.com/html/_1_hooker.html

Current RPM / Knots for anyone needing a comparison
I would like to know if this is about right also.

1 knots = 1.15077945 mph
RPM... Knots..... MPH
900........ 3.8........ 4.4
1000...... 4.3........ 4.9
1200...... 5.5........ 6.3
1400...... 6.5........ 7.5
1600...... 6.8........ 7.8
1800...... 7.2........ 8.3
2000...... 7.5........ 8.6
2200...... 8.8....... 10.1
2400.... 10.2....... 11.7
2600.... 11.5....... 13.2
2800.... 13.4....... 15.4
3000.... 15.4....... 17.7
3200..... 18.3...... 21.1
3400..... 19.6...... 22.6
3600..... 20.8...... 23.9
3800..... 24.2...... 27.8
4000..... 24.5...... 28.2
4200..... 25.5...... 29.3
4400..... 26.9...... 31.0

There was a light chop, a little wind and the trim issue
I expect these numbers to improve a little.

 

[old_navy]

Before I forget it will stainless steel prop help any?

 

[Nehalennia]

Before I forget it will stainless steel prop help any?

I really like stainless. What pitch do you have now? I assume it's aluminum now.
With a WOT at 4400 now you'll probably want to get a stainless with the same pitch, but stainless flexes less so your performance should improve slightly. The real benefit is a stainless steel prop won't kill itself if you cavitate it.

 

[keokie]

Yes, stainless will help. A 15X17 Mercury Vengance with mild cupping does pretty well with that hull. Stainless works better mainly because the blades can be made much thinner since it is stronger than aluminum. Thinnner is more efficient.

Your list at high rpm can probably be corrected by adjusting the steering trim fin (forgot the real name) on the underside of the anti-ventilation plate just behind the prop. The other possibility is you had too much negative trim. If the boat sits level at rest, it should not list at higher rpm.

 

[Cap10Pat]

Hooker's bad enough, but you and your buddy going out on the lake for strippers?

Would you mind posting your hull ID. I'm wondering about the model.

I have a 1980 Weekender 260 with a 5.7L/350. I had a 17in aluminum prop and went to a 17in Merc Mirage Plus. The Mirage grabs too much water. I need a Mirage 15 or maybe the Vengence 17 would work well as suggested above. The boat came with a Vengence 15, but that was too small. Depends on the health of your engine, and shape of the bottom. I'm not sure if yours is changed since mine. You'll like the stainless prop.

 

[old_navy]

Yea - you're the second person to catch that! The first was of coarse my sister-in-law!:smt021