Prop size help

[Frank Pristera]

I just purchused a 1991 350 Sportfisherman Convertible w/Twin Marine Power
454 SportPac engines. It's proped with 23x23 1/2 4 blade props. I'm turning 2800 rpms at WOT. I cannot read the transmission plates for the gear ratio,
there Borg Werner Velvet Drives. The previous original owner hasn't got a glue,he repropped in 2007. Is there anyone out there that has the same boat
that can help me.

Thank You

Frank "Cookie Monster"

[Jus trollin]

I have the same boat the trans ratio is 2:57:1 with 1 3/8 shafts H.P. is 310.
I am turning 4500rpm with 20X24 in. three blades with poor control backing into slip. I changed to 20X24in. 4 blades and lost 200 rpm but gained some control. Hope this helps

[Esquire]

It sounds like you are way overpropped. I have Crusader 8.2 (502) gas engines in my 36 and I cruise at @ 3400 to 3600 rpms, my wot is 4800 to 5000 rpms. A wot of 2800 rpms is more like a diesel than a gas 454... Call marine power and they should tell you your engines WOT rating, if I am right and it should be in the 4200 to 4600 range you need to get rid of those props, they will ruin your engines.

[Choppy]

Hi Gents,

I have a 1990 350 with Crusader 502's and although I can't seem to find my prop specs right now (I believe they are 18 x 19 and not sure of the cup), can you give me an idea of what your cruising speed and fuel consumption is at the 2800-3200 RPM range? I have always thought my boat should be faster (we cruise at 10-11 knots) but my mechanic has assurred me that we're OK..........thanks!

Aloha,
Choppy