vonwolske

It seems that if you mount only one drive, you will have to add a center pod and lower the drive such that the down angle does not push the stern up and the bow down. By the time you do all that sheet metal work, you could have added a second drive and used a splitter box for less cost and better performance.
Howard Arneson has a single drive, but he has fought against prop walk for a long time.
Keep us informed on what happens.

999JAY

This boat was originally rigged with a single lamborghini V12 and a SSMVI drive.
I think they had similar problems with stability but the drive ratio was 1.5-1 which increases the torque at the prop. I am running 1-1 with a prop speed of around 6000rpm.

Is prop walk a common problem with single engine cat?

vonwolske

to Jay;
I think prop walk is a problem with any surface piercing propeller that has only one prop in the water. This is also true for stern drives with high x dimension. If there are two drives, the side forces tend to offset each other. Hence, the two drives and splitter box approach. But, I am not the last word on it.

On the other hand, people run single engine outboard raceboats with high X dimension. I assume that they just learn how to handle it.

999JAY

Yep hydroplanes as well they run a single surface prop with turbine power, although there prop speed if very high maybe this is the key to it working.

Cheers

nocigarette

Very interesting project,,,,,,,way cool you are duing that extreme of a project.....A lot of measuring and math......keep us posted good luck

X-Rated30

Just curious, but what pitch and diameter prop are you planning to run? I have to wonder about planing out. I would think that cleaver prop is just going to cavitate like a mofo spinning it to come out of the hole.

Also, I have driven a SOB race boat before and you have to countersteer the whole time. I have no reason to believe a big cat would act differently unless somehow the weight is a factor. Did you ever drive it with the Lambo/#6 combination?

999JAY

Haven't worked out the prop details yet probably 17 dia 29 pitch 4 blade or there abouts.
Never got a chance to run the boat with the lambo setup from what I heard It was a handful. I think most of the problems were related to torque at the prop because of the ratio they were running 1.5-1.
I wont need as much torque at the prop to get the boat on plane because the full boat only weighs in at 3 ton fully rigged with fuel.

Rik

We have never had any issues with the propeller torque on our boat. Breaking propeller blades is another issue, but handling is not.