Driving/ Tech Advice???
 

Hey all,

Having just bought my first OffShore/Performance boat in August I've got a question for ya that's been bothering me.

The boat: 1996 26' Scarab w/ 502mpi

During a trip to LOTO the weekend of the Shootout, about the 6th time I had this boat out. Water conditions were pretty typical for LOTO on this weekend. 2-3' chop w/ some bigger water thrown in for good measure.

I had 8 people on the boat, full of gas, 80 gal. I was able to run pretty consistant at around 40mph, working throttle, trim, and tabs regularly. When I would come up on some REAL large water from other boats I would back off a little. When doing this, my boat would blow-out. (I guess that's what it's called, the prop would come unhooked) It would ALWAYS happen when I would back off in large water. I would try to catch it by trimming down or quick throttle adjustments, but no luck. I would have to completely let the boat settle in the water before I could load the prop again. VERY irritating and embarrasing.

Was there something I could have done different when driving the boat?

Could it be my prop set-up or X dimension?

Maybe the trim or where I had the tabs set?

I had the lower unit trimmed up to about 4 on my guage. Had to drop the tab couple of notches to keep her in the water.

Ideas anyone?????

All help is appreciated. I am learning.


Buck
#183

Sounds like it was falling off plane due to the weight and lower power setting. This would cause the boat to "see-saw" forward and lift the prop into jumbled water. The air in the water would cause it to cut loose. In that size boat it is very hard to get any kind of real performance with that much weight on board. Add to that the fact that the hull is designed to run "loose" and you see why performance would be impaired. I would try pulling the drive in and maybe adding a little tab to help it plane but you may not be able to make that a good "people hauler". Maybe you could get one of your freinds to buy a boat and split up 4 and 4 :D

Oh BTW, if you continue to need the ability to cart around 8 people, maybe we can trade, I got a nice big, wide 28' cruiser that will schlep them all around in comfort :D :rolleyes: ;)

LOL! Wish I could afford something bigger right now.

I figured the weight in the boat had a lot to do w/ it. It just seemed to happen a lot, enough to be very irritating.

Guess I need to find some freinds w/ more money, huh?

Buck
#183

what prop are you running

Well, I have a 30ft Scarab...

If conditions permit it, and its safe... its better to HAUL ASS thru it... or OVER IT, then get stuck in it.

:eek: :eek: :D :D

When running slower heavier loads change your prop and prop down--2" smaller and use a 4 blade bravo prop. Remember no one prop will do it all. I have 2 depending on conditions.

FloridianSon,

I think it's a 23P Mirage. Heavy on the think!


Nick, I like the idea of just staying on top of the bad stuff. Some of the passengers were complaining about that part of my driving. Guess I should have told them to swim where we were going.

Marty, the idea of a different prop for that kind of load makes sense to me.

Buck
#183

Remember.....Loud pipes save lives.

"Maybe the trim or where I had the tabs set?

I had the lower unit trimmed up to about 4 on my guage. Had to drop the tab couple of notches to keep her in the water.

Ideas anyone????? "

Sounds to me like you might have been trimmed to high, don't know where 4 is on your gauge, your prop shaft should have been still pointing down, trimmed in.
If you were going to try running on top you would probably want the propshaft and tabs parrallel with the bottom,
if you are running the tabs down it doesn't make sense to have the drive trimmmed up past parrallel to the bottom.
Hope you can understand what I'm trying to say.
Caleb

Buck, I've got a 23P Bravo 4-blade on ebay right now. I does not include a hub. No reserve. That would probably help you out a lot.

Buck,

I had a 26 Scarab w/ a labbed 23P Mirage plus. I never had the problem that you are experiencing but would concur with a few of the opinions expressed earlier. It is likely that you had too much weight in the boat combined with too much trim and not enough tab. In the heavy water that I run in (Atlantic/Chesapeak Bay) I would exit and re-enter with no problems with blow out even with my "full load" (4 adults 6', 190#). Recommend that you add more tab and reduce trim. Also have someone help you determine the "true" positions of the tabs/trim as it relates to your gauge. I have found that there is a lot of variance in the adjustment of the cables.

What RPM are you getting with a "normal" load combined with ideal conditions and trim? Has the prop been labbed before?

Where the heck did you put (8) people in a 26 foot Scarab???

Tell at least (4) of them to but their own boat. <g>

Padraig

Buck183,
I have you beat .... I've had nine people on mine once. Myself and 3 buddies and the other 5 were some strippers !!
Luckly we didn't have to go far , strippers or not it was not a very good ride.
Usually I try not to have more than 3 total on the boat... it goes faster that way !

Also the best all around prop for that boat with stock power I found was a
22p Hydromotive 4 blade.

Hey Buck,

I have experienced the exact same thing you are talking about. I run a 25" Mirage plus.

I think part of my problem is the rpm range where it occurs. I get a lot of prop slip in the 2800-3200 range, even in calm water. I guess that is somewhat normal with a bravo 1 to slip a bit coming out of the whole to get the rpm's up then the prop will bite.

The problem is when I am in rough water and I am forced the stay in that rpm range, the prop keeps slipping. Even if I am trimmed all the way down it still won't hook up.

Dave M.

Dave...I feel your pain.

I think I had a combination of things going against me.

Too many people
Not enough speed for conditions
Wrong trim/tab settings
Maybe different prop

Time to trade some fat, beer drinking, hairy, mooching, ugly freinds for some fly honeys I guess. Anyone wanna trade? Didn't think so. :(

jbrauer...I am interested in the prop, just not a good time for me right now. Too many bills at once. That and the wife seems to think she needs a new vehicle NOW! LOL Thanks for the heads up though.

Buck
#183

Time to try a few different props. It can make a world of difference. Try a 4 blade round ear. It may be 1mph slower on top speed but the boat will be far more enjoyable to use the other 97% of the time.

Catmando, you forgot.........and look better!
:D