What are reasons for using shorty drives on certain applications. I want to put an older Alpha SS on my 20 foot Searay, but want to know the possible benefits. First I should describe my situation. My 383 powered 91 185 SeaRay runs in the neighborhood of 76 MPH. At this speed the boat is lifted very high out of the water, to the point that pretty much only the back couple of inches and the drive are in the water. At 73 boat will start bouncing up and down and side to side. Will going to a shorty gearcase improve this or would this be a mistake and make it worse. I understand that a shorty gearcase is sort of like using a Jackplate, but without the additional setback. Any ideas?

Dont know about the setback, but do you have tabs on your SeaRay? This might be a more cost effective way to resolve this prob.

E.S.

i dont think a shorty will help you. it seems like your goin faster than you should be in that boat anyway. you'll probably experience prop blowout as well.

I've got tabs on the boat, but I have them mounted too far inboard. That's going to change when I cut the thru hull exhaust holes as the rams mount where the exhaust is going to go.

Bruce, I know the boat is going faster thanit was intended, but it sure is fun. Prop blowout is not really a problem since I put the nosecone on years ago.

Tomorrow I'm going to measure the distance from the bottom of the boat to the prop shaft. I was reading in some other posts that you want to be around 2 inches or a little more. (This might be boat specific, but it should be good to know.

Oh and the boat is very similar to the old Pachange 19. The OAL is 20'2" and has very similar hull lines. I think they took a page from the 19 footer when they made this boat.

The chine walk is indicative of a couple of things. It could be something is worn in your steering. It could be a balance issue. It could be a proping issue. Driver skill and hull speed also play into this. A good driver can drive with some chine walk. Skill won't make up for defective steering or exceeding a hulls capabilities. Right now, I'd guess that you are exceeding the hull's design. A shortie lower will make this situation worse. Try a different prop first to see if that helps. I'd try a Hydromotive Q4 if you can find one small enough. That's a stern lifting prop and it sucks getting on plane, but it's a very smooth high end prop. If you want more speed, you should also start looking at hydraulic steering. That alone, could help dramatically.

Well like I said it start at 72-73 and the boat goes 76 so I do have to drive through it and it has been doing it for a couple years so I have gotten pretty good at reading it. I won't let anyone else drive it at that speed because I don't know what they will do.

Anyway I tryed a Bravo 1 22 in prop a couple weeks ago, but it did not perform very well. It vibrated a lot at speed, but that might have just been a goofy demo prop. It also rocked back and forth a lot sooner than the 3 blade. I'm running a 21 tempest right now and this has been the best prop I've tested since it came out.

I'd like to put the hydraulic steering on it, but 3500 buck for that... I might as well sell this boat and get a bigger one and start over.

Sounds exactly like my boat before hydraulic steering,i also had a speed around 72-78 that it would get downright ugly,the nose cone makes it worse without hydraulic steering (if you didn't already know that). Maybe you could at least put a stabilizer on it,i think a shortie drive would make it worse yet,Smitty

Where can I find steering stabilizers? Also, without the nose cone the prop will blow out at about 64mph. Thanks for the info guys.

Drew marine makes them. If you never are going to add more power or look for more speed, then the stabilizer will help. If you are, then go hydraulic. A full system is the best, but a add-on ram is better than nothing.