Payton

I asked a question in another thread and it sort of got buried.

I know that shorter drives make you go faster, most of the time. They have less drag than a standered length drive. But, does that simply mean you will have less slip and run the same rpm, only faster speed? Or, will it raise your rpm and possibly create a need for more pitch on the prop?

Harper220

I'm curious also? I actually pulled the trigger on two IMCO shorties, so I hope it pays off with some better speeds using the same props.

I'd like to know if shorter drives reduce slip allowing more speed while using same props?

PatriYacht

Because they run closer to the surface, I would guess they increase slip. I know a few guys that had trouble planing off after installing shorties. The solution was to install 5 blade props. The shape of the case may reduce slip. I installed nosecones on my old boat with TRS drives. The speed stayed the same but the rpm's fell by 200. I think it was because the nosecone smoothed the flow of water to the prop.

Harper220

I really don't think it will increase slip running closer to surface, at least that's not what I'm shooting for. Cleaner water to props, better trim angle and less drag is my understanding of how to gain speed. I do run 5 blade props, so hopefully this will combat the planing issue.

Sean H

you won't be gaining cleaner water with shorties unless they are on a box....

speed usually comes with a prop change...

Beak Boater

The speed increase comes from less drag from the gear case. Everything is a trade off. Ususally with elevated drive heights, the boat is a little harder to get on plane. You will most likely have to go to a 5 blade prop of some type, Maximus, Hydromotive, Herring. Water pressure can be a problem getting clean water, not distrubed to the water pickups. You may also loose some bow lift. If your hull doesnt need alot of positive trim it shouldnt matter. It takes alot of testing to get everything right.

Harper220

Do you think I'd gain some rpm's on top end with same props though? I can only get about 4800-4900 rpm with my 496 ho's and Hydro p5x's.

I talked to Eliminator and was informed the 28 TD has never really benefitted that much by putting boxes on. They did recommend shorties though.

Sean H

you might gain the 100 or so rpm's to get to the 5k you need..

Harper220

I'm running Hydro p5x's, so at least I have that going for me...

I have a cat so the drives will have low water pick ups on them. Will this still pose as a problem?

jpclear

The new prop design technology promotes running surfaced (higher) with actually LESS slip and more overall efficiency. JULIE... WHERE ARE YOU?? You can explain it much better. --- Jer