Performance

[fullhouse]

Thanks Guys for all your comments. I will work on this.
Ron, the props were 20 x 25.5 and I had them reworked to 20 x 26 in order to speed up the boat. The transmission is 1.6 ratio vee drives.
There is some history that concerns me and seems fishy. Why did the boat come with an extra set of props that are very small like they belong on a gas boat? The engines were rebuilt by the previous owner due to a perfomance problem related to fuel going bad in the tanks from lack of use. The primary filters(racor) were 5 micron and a mechanic told me that the engines were naturally aspirated(?) and they would not get enough fuel with those. (the seconday filters are 5 micron) When I push the engines for a short burst they seem to blow oil out the pan gasket. The markings on the dipsticks look home made. I should probably gather alot more specs and think about having a mechanic look at it.
I will fill the tanks this weekend and log the miles to calc gph and check the trim tabs.
and I am beginning to believe that maybe I have a weight issue due to a soggy core?

 

[fc3]

Specs? That's easy. I have the full line specs from a CD-ROM Sea Ray was distributing in 1999 with their brochures. Companies weren't too web savvy way back then.

Unfortunately, it will only run under windoze.

Never mind. I did get it to work under Parallels. Who knew that Macromedia code was so good. LOL!

 

[BonBini]

From fcs’s very cool spec sheet, looks like your correctly propped. I was doing the math on rpm, drive ratio, prop pitch and came up with what tobnpr mentioned a few posts back, “props must be slipping like crazy” I’m thinking if you had a water logged core your boat would struggle to come up on plane and also struggle to make rated rpms with black smoke from the overloaded condition.

What do you think about the bottom paint job you mentioned aerating the props?

 

[fc3]

Have the props tuned by a shop with PropScan.

 

[quality time]

And I thought my boat was slow...

You're pretty much chasing the same things that I have for the past year and I haven't gotten anywhere but lighter in the wallet.

I average 21 kts @ 2400 and around 28 kts @ 2850.

-My props are 20x24.5, yours are 4 blades right?
-I run 10 micron in the Racor and the CAT on engine filters are 2 micron.
-I soda blasted and barrier coated my bottom, it made no noticeable difference.
-I too thought I had water hiding somewhere, I probed all winter long and never found anything major.
-My loaded weight is 24,000 lbs as confirmed by travel lift, have you had yours weighed?
-I have to run full tabs to get the best speed, which is hurting efficiency.
-I burn 27 GPH @ 2400 per my Floscans.

Our boats should cruise 23/24 kts easily.

As said previously, you need to confirm that your tachs are correct. My guess is that they are not.

If you find the magic answer, let me know. :thumbsup:

 

[quality time]

Also, you questioned the markings on the dipsticks. They are put on at the factory after the engines are set in place, so the "home made" look is normal.

 

[tobnpr]

Have the props tuned by a shop with PropScan.

Good suggestion, at a minimum, I'd have them sent out to be checked for condition/verification that what's stamped on them is what they "are".

If the props are "right", and the tachs are correct, it comes down to what we discussed on another thread a few months ago. "RPM's are RPM's"...

I still would photo-tach verify the tachs, and send out the props, then take it from there.