I have a 1988 30SS Sonic and everything is out of the engine bay right now. Someone has suggested raising the X by one inch, someone else by 2 inches. How much speed am I likely to gain by doing this? 5 MPH+ might be worth it, 2 to 3 MPH is not.

Any suggestions?

I think with a prop change to match, 5mph could be possible. I would buy Imco 2" shorties, if they turned out too short, drive spacers could be added to lower them.

Actually it was the good folks at Sonic who first suggested raising the x dimension one inch, given that I use my Sonic in heavy offshore sea conditions.

I'd like to know if anyone on OSO with a twin engine 30ish foot boat did change their X dimension, by how much, and what speed they gained.

GO4BROKE, you mentioned a prop change, to what? I am thinking about getting Bravo I 24 pitch four blades fitted to the new Bravos and Scorpions combination.

BTW Too Old, congratulations on getting a Sonic! I know you AND your wife will love the boat. You will find that she is dragging you out to the boat more often than not. Good luck with it!

If you want top speed a mirage plus was worth 2 mph on my boat over the b1's. I would contact a couple of prop manufactures about what to run with a shallow x dimension, perhaps something semi surface piercing.

Humm, I troll from my Sonic so the need for surface piercing props make me nervous. I think I'll do a one inch raise on the X at this point. Interesting about the props GO4BROKE, thanks.

CBR; You Troll From Youre Boat When Its On Plane ?? WOW!!! T
talk About "Ripping Their Lips Off" !!!!!!! Sorry Dude Just Funnin With Ya..........The only Time They Are Near The Surface is When You Running. You Thinkin Of Surface Drives??

J Ross indicated a one inch raise on my 42SS should net 2 to 3 MPH. I opted not to cause it seemed like a lot of work for that, however my transom is not curently stripped. Sounds like cheap speed if your already most of the way there.

Hey Madcow, I wonder whether one inch X move on a 31 footer gains more speed than a similar move on a 42 footer.

What do you think? Nice to know about your projected speed gain though. A two MPH pickup with Mirage props, and a 3 MPH gain with the raised X equates to a five mile an hour gain I hope.

I go 1 to 2 MPH faster with Hydromotive 4 blades than I do with Mirage's plus the boat performs better evey place else. I know it takes a lot to make a speed difference on a bigger boat. You might gain more than I would, I'm just not sure. Did you ask J Ross? He indicated to me that they raised all there X dimentions since my boat was built (1994).

I do not like the look of the Bravo I props. I really liked the nasty looking Ballistic props I had on the 270 HP motors, what do the Mirage and Hydromotive Props look like?