87 10 meter- do i need to replace cutlass bearings?

[BobCT]

I have an '88 and it only has one strut per side. Just doing the shaft logs now so I've been around this area in/out all week.

Bob

[RWS]

Mid cabin based design vs. the express cruiser design. The mid cabin based 10 meters feature:

engines farther aft
shorther shafts
one strut per shaft VS. 2 on the express cruiser
shallower shaft angle
different ratio gear
smaller props spinning at a faster RPM

Other than factory data does anyone know what if any difference there may be in performance data?

RWS

[gardnersf]

RWS,

Based on your performance specs posted before the diesel upgrade, the Mid cabin runs about a knot slower at all speeds. Not sure on MPG.

I find I cruise at 15 kts at 2800 RPM. Just about the fuel sweet spot but I have full tabs on. 3100 is nice, about 16.5-17.5 kts, but fuel burn is higher. Not sure where the secondaries on the carb open.

I will say I ran it for about 25 minutes at 3700 RPM racing a storm in. That was fun, about 22-23 kts but I could almost see the fuel gage move

[RWS]

Hi Scott:

The numbers I posted with the gas engines were with the larger trim tabs I installed in 2003.

The factory tab was a 9" fore to aft measurement. After consulting with the people at Bennett and analyzing the performance data they determined that the boat needed more lift.

The Bennet 12" tab WITH 3" DROP FINS doubled the lift and may be partially responsible for the difference in performance.

Interesting, with the 454's I really needed to use the tabs to get more kts per RPM at any given speed. Similar to an outboard, adjust the tabs and watch the GPS & R tachs change for the better. With the diesels the tabs have zero effect on the speed, just the running attitude.

I'll have to go back and look/see if I kept any data from before the tab change.

RWS