Trojan Boat Forum

I have the mid-cabin model with 454's. What max / cruise speed do you get and @ what RPM's. I get 14 knots @ 3100 and 23 knots @ 4200. Is this normal?

That sounds about right. We have a 1983 10 meter flybridge/aftcabin and with 454's at 4k we get about 19-20 knots and I'm sure our boat is heavier than yours.

1983 10 meter International Express Cruiser
454 gas engines 4 blade 18x19
fully loaded with fuel, water & "stuff"
2800 RPM .81NMPG 15.5 kts
3200 RPM .70NMPG 18.3 kts
4480 RPM .49NMPG 26.4 kts

after repower to twin Yanmar 6 cyl turbodiesels
four blade 20x20
fully loaded with fuel, water & "stuff"

3200 RPM 20.8 kts
3400 RPM 22.7 kts
4000 RPM 27.1 kts

I don't have fuel usage meters on the diesels.
The non mid cabin models swing a bigger prop at slower RPM than the mid cabin models as the mid cabin vessels have the engines placed farther aft with a steeper shaft angle using a different ratio transmission spinning smaller props faster. The bigger props may have somewhat less slippage and therefore be a bit more efficient.
Hope this helps.

RWS

PS - I still have 2 complete sets of props, digital tach syncronizer and flowscan for the 454's if someone wants to take the whole lot off my hands.

That sounds great! When the snowbirds go home and I have a little time, I'll give you a shout...would love to see those diesels settled down under the hatches.

I have been getting about 19mph at 3100 rpm using 1.1 g/p/m in my F-36. But I think I was fortunate to get 2.5 to 1 trannies so I can spin a big, 4-blade prop...think it's a 22x19.

Of course, it may be stressing the engines a bit more(not sure), but the faster they die the faster I can start looking for diesels.

Tony in Fort Myers
1981 F-36

Tony,

Those are very respectible numbers given the size and heft of your vessel. The hull and planing surfaces are siginificantly different in the International series which accounts for the difficulty in comparing oranges to bananas.

All the numbers in my data are for Knots, NMPG and Nautical miles not statute miles.

You're welcome to come and see her anytime, just send me a direct e-mail.

RWS

1988 10 meter with 4 blade:

3200; 18 knots .7 NMPG
3500 20 knots .65 NMPG
4300 26.5 knots .5 NMPG