Skater 21 build off/setback and rigg height

**Semifreak** · 04-04-2017, 05:21 AM

Hi!

A couple of years ago I got myself a project boat. A build-off of a Skater 21. After have cleared up wiring and interior plus trailer I managed to go approx. 80 mph (revlimiter) with a Promax 300 and a Bravo 28. But realizing that I took 3/4 gallon per nM I decided to go for an Optimax.

However I did some rigging differences too, first it had 10" setback. So I got down to 4. And also I raised up the motor a bit on the lift. Before the max height was approx 5-6" below the lowest point (put some straight wood to get the straight line from the steps on the hull. However it maxes out now at 78. Running Pro ET 30" so I should have redline at approx 92 mph. Also it doesn't respond well to trim without setback either.

Before the purpoise were easy, max trim down until 70 mph the full thr and trim and it just took off. Now when doing the same it just purpoises until I trim a lot, the it keeps it up. So I purchased a 6" Bobs instead. Does anyone have a good starting point on rigging height (when maxed out on the lift that is)? I'm running a Sportmaster HD with stock pickup/nose cone

Thanks!

/Best regards Andy

**Trimmed Out15** · 04-04-2017, 05:42 AM

When i measure, i level the boat and the motor, take a straight edge from the bottom of your sponson and go to the center of your prop shaft or even the center of your bullet of your sportmaster gearcase. Taking a measurement that way, your bullet or prop shaft should be at least an inch above the bottom of your sponson. Those boats require no trim if set up properly. If anything maybe even a little negative trim. Basically run that motor as high and level as possible until you run low on water pressure. A level but elevated boat is a fast boat, also a safer boat.

**Trimmed Out15** · 04-04-2017, 05:44 AM

Also which optimax and what gears are you running? Pro Et will be your best prop

**baja200merk** · 04-04-2017, 09:02 AM

start out with propshaft even with bottom of sponsons maybe a bit higher. Jack it up a bit as you go through the hop. Don't turn with it jacked up or chop the throttle if you do turn

**Semifreak** · 04-04-2017, 02:11 PM

Sorry guys! It's a 250XS powerhead '05 , the high powered one with 6300 rev limit. In a 2012 300XS 20" offshore mid with 1.75 gearing HD propshaft. My goal is at least 92 mph. The reason for me with the topspeed, is to be able to use it over the purpoise range which with mine lasts until 82.

I have a slight thought about it's ecu/tuning, or just a very good condition head. Since the last owner tried it head to head with a 300xs powerhead on the same mid/rigging and it only had a 2 mph difference, however it was a quite heavy boat.

Very good input, the prop shaft level or 1.5" up is that the highest setting? Meaning I go for 1.5" up with lift in the upper setting and -3.5" in the lowest/for easier plane?

Sounds amazing to get the setup good enough to not need a lot of trim. I found out that the current lift has a 2 degree offset / crooked. So the motor is tilted to the right. Which I guess takes some speed also.

I guess the 32" would be a solid prop for the 300xs so I hope the 30" will match the 250. Otherwise I'll look out for a true stroker head

Thanks for all the input!

**Trimmed Out15** · 04-06-2017, 06:35 PM

Any updates?

**Semifreak** · 04-07-2017, 09:28 AM

Originally Posted by Trimmed Out15

Any updates?

Haven't got the chance to try yet, we still have some ice on the lake so I'm currently getting quality time with polishing. I mounted it about -2 inch std so I'm able to go up to +3 inch. I will also replace the water pressure sensor so I can check water pressure. Does anyone know if the 3 litre opts only have one water pressure sensor? I found another one laying under the cowling not sure if it was connected.

i will also borrow race vests for testing the last miles. I'll get back when it's done

/Best regards, Andy

**Risco** · 04-09-2017, 02:53 PM

You should in stall a water pressure gauge that's how I drove mine. Get on plane all the way down then anything of say 45mph I just used the water pressure gauge I kept it at 5-10 psi . I ran 250 with a 1.62 and a 30 and ran 94 mph light 92 everyday with 2 people.

**Trimmed Out15** · 04-10-2017, 08:43 AM

The gauge is a must to get the best speed, or an external pickup

**tux974** · 04-10-2017, 10:19 AM

All good info and advice above!
Water pressure gauge is a must!
If you run a 15" motor external water pickup is also a must!
IMPO, Set back no more then 6" and if you are running a 3.0L 15" is the way to go! Not to make the boat faster it is just to bring the CG down or it will need to have that 3.0L power head jacked too high.
Just finished rerigging one with a 6" Bobs and a 20" 300X and it runs well in the high 90's even touched 100 with a new driver, fuel and 2 persons in the boat.
It will be going to 15" mid shortly and with external pickup.

If you only had 3 holes in your dash the most important gauges that should fill them are. Temp, pressure and tach.
GL and be safe!

**mrcrsr** · 04-10-2017, 10:38 AM

We typically run 8-10" setback, run the motor as high as u can go and still have water pressure. U really need 1.62 gears with the low rpm limit u have.and I usually run neutral trim at wot

**F14** · 04-10-2017, 08:42 PM

Do the single engine 21s have a small center pod like my 24?

**tux974** · 04-11-2017, 05:40 AM

Originally Posted by F14

Do the single engine 21s have a small center pod like my 24?

Yes!
Your 24 has a bigger one from a 36'

**Esox4130** · 04-11-2017, 07:22 PM

Originally Posted by F14

Do the single engine 21s have a small center pod like my 24?

My twin 21 has the small center pod too

**Semifreak** · 12-10-2017, 02:55 PM

Sorry for the late reply guys, been up to the ears with our newborn which we got just after my last post.

I set the boat up with -1” and possible to go up to +4. Setback at 6”. Biggest difference from having the 10” setback is having to trim more. Quite a lot, and in the beginning I really struggled to ride it. Ended up with too much trim and lift and had some small proprides. But I stopped at about level with sponsons. Got myself 85 mph at 5440 rpm. Incredible 4% slip with 1.75/30” Pro ET. But the 250 struggles since I did calculate with more slip so I was expecting higher revs at that speed.

So a 28” Pro ET would be a perfect fit. However they don’t make them anymore.

Can anyone recommend anything else than the Pro ET, similar which could work for me? Tried Bravo 1 28”. But the slip of them are awful, about 87 mph at 6500. Long way from the 92-95 at 6300-6500 I would like to get. I’ve got mixed feeling about Pro Max prop, everybody seems to sell theirs.
Some writes about the Blaster and Drag 4. I love the Pro ETs grip but I feel it seems a bit nervous when it has packed air. Drag 4 seems popular with the Liberators, looks easy to handle watching Randy riding them. But that might be the hull design more than the prop.

But it they seems to run more slip so I guess another 30” and looking for more slip might be another solution. Any prop recommendations with the Skater hull?