Trojan Boat Forum

Hi everyone. Im about to buy a 12 meter convertible but it doesn't have a fly bridge! The boal fist owner is the latw Amire of the State of Kuwait Shakh. Nawaf AlsabahThe boat year is 1991 and has been through a repower with Yanmars 6 CXM-GTE and ZF transmission with ratio of 1.235:1, i sea trail the boat and i notice the wot speed is 28mph @2700 rpm(clean n new antifouling paint) witch is slower then what i thought. I lift the boat i checked the props and from the first looks i noticed the props shape is quite different then the other sport fisher boats setting around and next to our boat and the props size is 24x24 im sure the boat can go much faster with 465hp Yanmars up 30+knt at WOT. i will appreciate any help from your experience guys. I wish i can post the pics of the boat and props but try.

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Where to start? Do you have the rpm rating for your engines? I am thinking 3800 rpm? If this is true 1.23 gears is a very poor choice, should be closer to 2 to 1. Second, the props look like crap, Looks like a lot of pitch was taken out to make up for the trans ratio. It does not look like 24" pitch I could be wrong. I would talk to a good prop shop.

Prop nuts on wrong and that spacer???

First thank you for replying. The max rpm is 2750 and get a reply from Michigan wheel says that the prop i need is 18 pitch and 24 diameter 4 blade,. 86 EAR #7cup And might be some dial after the seatrail amnd the speer should be 30+ knot.

Rashed wrote: ↑Thu Jan 09, 2025 7:34 pm First thank you for replying. The max rpm is 2750 and get a reply from Michigan wheel says that the prop i need is 18 pitch and 24 diameter 4 blade,. 86 EAR #7cup And might be some dial after the seatrail amnd the speer should be 30+ knot.

Hopefully, that will help. Even if the engines are rated at 2750 rpm the gear ratio is bit off. But its what you got. Factory Detroit Deasels were 450hp @2500 rpm and used 1.5 gears FWIW. So ideally I would a trans ratio of 1.5 to 1.75 would be better. But that's a major expense. Hopefully new props will do it.

Thank you Prowlersfish and i hope that too.