HiPerf2000

iTrader: (2)

Did you ever get work from Julie about the Hydros ?

steve chalupka

I hope all of you don't mind if I interject here. I too am a Sonic owner ('04 Prowler, 500efi, ITS, XR, kplanes -- the works). I've read dozens ans dozens of articles on the same topic regarding prop selection for Sonics. Mine came from the factory w/ a 26p Bravo one. Could only turn 4750 rpms. Way too much prop for this boat. Put on my buddy's 24p B1 and went up to 5150rpm's.
What I am really concerned with is the same subject almost everyone talks about (regarding Sonics) --- the continual porpoising of these boats and the constant need for use of the kplanes. I guess I'm getting a little tired of hearing "you've got to get these boats on top of the waves" or "they run better in rough water" or "once your at 50 + miles per hour they run great!"
After my X dimension was checked I was told (by an individual synonomis w/ powerboats) that the best way to eliminate this porpoising problem was to have the hull blueprinted. I'm sure you all know what this costs.
What's going on with these Sonic hulls? Are the molds dated? How come no one and I mean, no one returns my calls at Sonic? Richard called me weekly before my wife and I made the decision to buy a Sonic. Now I don't hear from him, Bruce never calls back, Fred is gone Mindi doesn't return calls.
There are alot of questions that need to be answered.
To finish. I spoke to Julie at Throttle Up. Nice person. Said she would run some numbers on my boat and make some recommendations. I thought that perhaps the new 5 blade hydro would do the trick. It appears Prowlers need stern lift. Hope my boat settles down and begins to run right.
Sorry for venting, but almost all Sonic owners (Julie agreed with me) have similar problems. Believe me I read dozens of other boat manufacturers forums and they are not having these types of hull design problems. I didn't have these on my Baja and it ran in the low 80's with no tabs at all!

MikesSonic

Hi All,

While I am a new Sonic Owner (2000 358 500EFI's), I have considerable boating experience. The porposing you refer to is a characristic of the boat. All boat designs are a trade off, Want a fast boat in rough water, or a fast boat in smooth water, you can get one but not both, same with performance, want a big roomy cabin or a fast boat, can't have both... The Sonic hull and weight and balance leans towards great performance in rougher water. The trade off is you need tabs or a lower drive position in smooth water. I have found neutral drive position (2 on my boat) and plus one from neutral tab position eliminates the bounce at lower speeds. In rough water I do not need as much tab.... I have accpeted this as a feature of hull and weight and balance in the design of the boat... Any thought from more experienced Sonic Owners?

Mikee
2000 358

bn

I know that this thread is getting off topic, but I have to say that my 31 SS does not porpoise at ANY speed, in ANY kind of water.

splashandburn

My 31SS did not need any tab either but now I have an 02 358 and need to run with a ton of tab unless I'm running at or near full throttle. With 2 people on board I will run with my tabs at "6" and my drives at 2-3 , this is all that keeps it from bouncing. I've found that with a full load of people on board (7 or 8) I do not need to use nearly as much tab - what's up with that? It almost seems like there needs to be a ton more weight in the rear to keep it down.

Thunder32

Mark-
Julie at Throttle-Up never called me back. I got a set of used 28's and have just about eliminated the porpoise, and mid-range is better. (2003 358 w/ 500EFI's)
3800rpms at 59 GPS, WOT at 76

I have the pair of 26's in the garage. if you want to try them, just give me a call.

Adam
cell# 540-847-3124
home# 540-891-8268

bn

I am not sure where your neutral point for your tabs is on your boat, but my tabs are at neutral when at 5. So moving my tabs to 6 is not a "ton" of tab for me. Check to see where your neutral point is for your tabs.

splashandburn

I used a straight edge and ran it across the bottom of the boat and it looks like they are "level" with the trailing edge of the boat at 3 or so. Is this what you would call neutral or is it where it actually breaks below the surface of the boat or hits the straight edge?

bn

I consider neutral being level with the running surface of the hull.

Sydwayz

iTrader: (1)

Neutral is when your cavitation plate is parallel with the bottom of your boat.

Best way to do this is use your tongue jack to adjust the bottom of your boat to level, using a level.

Then, adjust your drive to the cavitation plate being level; (matching bottom of hull).

Mark your indicator with a little tick mark with a Sharpie so you always know where neutral is.