1995 22' Scarab 260MERC Planing Issues? Trim tabs?
 

Hey everyone. I am new here...

I just trade my RV for a 22' Scarab. It has a 260MERC in it with a Alpha drive. I am not sure of the pitch of the prop, but it is a stainless 4 blade prop.

I got alot of useful information from the people on iboats, but wanted to get more opinions.

I have taken the boat out 2x so far...

The first time I took it out, there were 2 of us in the boat with 1/4 tank of fuel (it holds 60 gals). The boat took of strong, got on plane and topped out at about 58MPH at 4800RPM.

The second time I took it out, there was 5 full size adults with a full tank of fuel. The boat has serious problems getting on plane. I had the trim all the way down and the first time I just went WOT pretty quickly and it took a full 20 seconds to get on plane. After about 10 seconds it felt like the prop was "blowing out". Once on plane the boat did well and shot up to 50MPH at about 4500RPM, not quite the same speed as before, but close. I took it down in throttle and back up a few times and could tell that the hub was not spun.

I got some advice on iboats and one thing I found was the transducer for the depth finder was mounted directly in front of the prop. I am removing it. It may be causing some aeration of the water going past the prop.

I am trying to figure out the most efficient way to fix this issue. I want to be able to pull skiers, but I don't want to sacrifice all of my top end speed either. I don't want to drop to 45MPH max, just to be able to get on plane quicker.

I obviously need to figure out what size prop I have... and go from there. I am also looking at a "Whale tail" (recommended by boat dealer) or a Trim tab setup.

Any thoughts would be helpful!! Thanks!!

http://i37.photobucket.com/albums/e9...ab/Scarab2.jpg

and YES, this photo is March in AZ. It was 90 degrees the other day.

Don't get a whale tale. Those things are useless IMO. It may be helpful to drop down a pitch size in prop. You shouldn't lose much speed, and you may gain something if you can get your RPMs up to 5k. What motor do you have in that thing?

Another option may be to send the props to BBlades to have them labbed. It sounds like you may not be too far off in your prop selection. Some fine tuning may do wonders for your boat/setup.

Good lookin boat! The guy in the background has the tallest bimini top I have ever seen :lolhit:

You need to check your pitch AND diameter. You may be better off with a 3 blade with the engine you have. I had a 22 for several years. Mine had a 310 and if I remember right, the prop I found that ran the best back then was a Merc Laser? They have a lot of bow for a 22 and when they are full of adults there is a lot of weight toward the rear of the boat so they do take a little bit to come over on plane. Mine did have tabs and I would definitely use them in those types of instances. They are a fun boat. I loved mine while I had it.

I had a 96 22' with a 330 Horse 7.4. 3 blade Mirage props are what worked best. We had a 23{ and a 25P. The 23 hopped up on plane but bumped teh rev limiter on the top end. The 25 was slower out of the hole but ran in the right RPM ranges. Other people have told me that 3 blades ar the way to go on these boats as well.

Here we go, dont put a whale tail on it , it will keep the bow lift down and loose top end. A four blade will come on plain a lot faster than a 3 blade . I have a scarab 22 with 600 hp or so and i run a labbed 30 bravo 1. i think maybe a 22 pitch would be great on the boat and come on plain real fast. I f you want put some electric tabs 8x12 on it and that would help when you have a full boat. . I think your rev limiter is set at 4850 so forget about going to 5000

The transducer's location should have no affect on getting water to the prop while you are coming on plane. I would leave that alone. Call Brett at BBlades and he will set you up. I would also considering adding a set of trim tabs. Also, sometimes less throttle is better coming onto plane. Roll into the throttle gradually and when you feel the prop start to blow out back off and let it "catch up" before giving it more throttle.

I tried to back off, but it didn't seem to help much just stayed off plane for longer. I am not suing the transducer. It is just hanging there and was from some Garmin equipment that the previous owner took off the boat. I am going to see about re-propping the boat, but would hate to get a new prop at $350+ and not get anywhere with it.

I like having tabs, so I think I am going to try the tabs first and see if that helps, then play with prop sizes after that.

Its a 260HP MERC

I have a nice used set of boat levelers ready to go...PM for details

Is this your listing, or did you just find it for me? I went online and found out what the motor specs are. 4200-4600 WOT. I am not 100% sure if my tach is correct, but I was running 4500-4800 at the lake the last couple trips. People are saying to go down in pitch, but according to this, I may want to go to a 3 blade prop and go up in pitch. I just need to figure out what pitch I am at right now.

The boat came with a 3 blade mirage 23 pitch, the ride better with a 4

I have a 4 blade now. According to BBlades a 3 blade is faster, but a 4 blade has more control, so you are prob right about sticking with a 4 blade. Im a newbie. The prob stuff is a little confusing.

If your current prop is a 23" and that can run 58 @ 4800, then you should still be able to run 52-54 @ 4800 with a 21". That is assuming your drive gear is a 1.62 and 8-12% slip. A Revolution 4 would be a great allrounder for sure. IF your drive ratio is 1.47 it's a bit different. Then your current slip is 18%, and that is high for that boat, and there might be an issue. By issue I mean the prop you are running now is just plane wrong for the boat, and you should start from scratch and go baseline testing.

Good luck.

The above text is my definition of confusing. I will mention to my boat mechanic though.

If you want. pm and i will give you my cell and we can talk scott

You can run that 23" when only 2-3 people are in the boat, but you should get a 21" 3 blade for those days you plan on hauling five people around

Sorry. Not trying to be.

Here is a quick explanation of prop slip. http://www.brianrogers.net/boatpropslip.doc

The other thing I mentioned was simply the gear ratio of the drive. Usually your engine package came with the 1:1.47 gear ratio, but the 1:1.62 ratio is pretty common as well. Should be written on the left decal on the upper part of your drive.

I will check!! Thanks!

1997 scarab 22 with 300hp 7.4 25 mirage plus prop 63 mph with 2 people and fuel. Put five people in boat and barely get up on plane. Fast boat hull, slowest on speed plane was about 22-23 mph. Hard to keep on plane with a skier behind or pop a skier up on plane. Looking back, wish I would have added tabs.

It says Alpha One and then 1.50R and then a Serial #

So it's not much a ski boat. I figured that when I got it. It was between the 22' Scarab or a 1980 Hallett Open Bow Jet boat. I think I made the right decision. I am not trying to pull a skier. Probably a tube, maybe a knee board and that is about it. I think I am going to add the tabs. I found a guy on here that has them. I think they will help alot.

I have the same boat with the 7.4 and the 23P 3 blade Same problem, 2-3 people on bard and all is great but when I get more than that it is a dog to get on plane. I hope to go to a 4 blade to help out.

I don't want to hijack your thread, but how is your windshield done? Is it painted or gone Great looking boat.

Thank you. The windshield is gone. I do have it and was thinking about putting it back on, but it does look better off. It is dark smoke in color.

Curious... What are your speeds with the 454? Are you running a Alpha or Bravo Drive? After getting on here and chatting with people, I have decided to do the following:

#1 - Trim Tabs
#2 - Prop
#3 - Interior Upohstery (wasn't discussed, but adding it in here)
#4 - In a year or two.... 350 with forged internals with twin turbos running 5-6psi boost and run the Alpha Drive easy til it pukes and then get a Bravo 1 drive.

We shall see what really happens.

I need to get rid of my turbo sandrail before I do anything major.

Sounds like you're on the right track. You're not going to believe the difference the tabs make. Reality of that size boat is even minor changes in weight makes a big difference........that was like a Mr Obvious thing. Seriously though, make one change at a time so you can document the results.

Mine ran a little faster with a 502, but you are right on ,with the rest.

I get low 60s on the GPS. I love the boat, it is the perfect size for the lakes I run in and will hang with some of the bigger boats, plus the 454 with open pipes (silent choice) gets lots of attention . I am very happy with mine, it is my first boat like this. I want to do single hydro steering and planes, but I have some other issues to fix first. Like you, my upholstery is out right now getting a once over. I plan to upgrade some components, carb, intake, cam, exhaust to get a little more out of it, but I don't want to sacrifice low end, reliability or economy (with a snicker) in the process.

If you do a search there are a few threads about this same topic. I had one with a 7.4 Bravo combo and I found the best ski prop was a 22 Bravo. I felt the K-Planes I installed weren't worth what I spent, I didn't even use the K-Planes for sking after I went to the 4 blade 22 Bravo. If I used them they just made a funkyer wake. I think with the less weight of a small block you are better off. For speed I found a 25 Mirage was best. Doug

I used to have a 22 1997 scarab had it for 10 years and through out the ten years I put the external steering and 12 x 18 eddie marine trim tabs imco power flow exhaust K&n air filter It had the 454 mag 385 H/P the boat ran 74 on gps at best with a 25 pitch prop three blade