XB21 Skid Planner Testing

[River Rocket]

It's been a busy fall testing props. I thought I would change things up and do some alternative testing as well and pulled the skid planner for a few weeks.

I run the original longer version. XB21 Prosport 300xs 1.62's and 10.5" setback.

I was shocked by the results.

Both my 30 promax and 28 P3 ran the same or better 5-85 numbers with the skid planner off. In fact, I had my best 5-85/90/95 run with the P3 with the skid planner off. It also ran its best top speed ever with it off.

Bow rise was higher, but it didn't seem to make that much of a difference as the time to a given speed was the same or better on the P3.

I took video of the skid planner and lower unit before and after, but unfortunately the gopro was lost on the first run with the skid planner off. Weird that that happened as it held on for many 99mph runs with the skid planner without an issue. I think the additional bow rise caught it.

I was really interested in the ride. I was hoping for ride improvement in the 98 and above area. The ride under 95 didn't change. The over 95mph speeds did become poor and I never pushed over 97 with the skid planner off. I wish I had the video as I suspect that my motor needed to go up as it felt very similar to what it feels like when I run my motor a 3/4" over at speeds over 95. My water pressure was up as well. So that supports the theory. Unfortunately, I'm maxed out at 1" above with my current setup so I couldn't go higher.

For the down side, the big wheels sucked to get out of the hole. It's not like it was a 1 second longer hole shot. It was a solid 10-15 seconds longer to get on plane. The data logger flat lined at 8mph for an eternity. I got passed by kayaks and airplanes were dodging the nose of the boat it was so high........

For the 95 and above speeds and crappy holeshot it went back on the boat. I'm undecided on my next step. New Jackplate or cut it 1" shorter. For now it's not worth messing with.

Just thought I would share. I see the question come up on occasion.

[AllyFishing]

RR, you have the original stock version right? I would be curious to see your results and opinion on the skid planer that "replaced yours" (meaning your long original version) which is about 2" shorter and has a concave cut out in the center as opposed to straight across. My guess is the hole shot will be much better than without but not as good as the original long one you have now.

Clarification..."replaced yours" is the one that I have on my 2013, Tim P has on his 2013, Hooken has on his 2016(?) it is a shorter one with a concave cut out between the flutes on either side. AND I'm told there was to be a "newest" one on the 2017 models but I had not heard of any confirmation on that yet. Darris mentioned that to me at the rally this past June.

So, I urge you to get one of the model like on the 2013 year boats and I bet you will be pleasantly surprised overall......but not on hole shot. Not as bad as what you experienced but not as good as the original stock length

[AllyFishing]

Oh, and another thing...kudos to you and Tim P for being able to run 30P props on a 300 with 1.62 gears!!! Had I known to put 1" holes in place of the standard PVS hole size I may still own my 30P XOB that Tim now has and runs the crap out of it!!! haha But I'm glad he has had good luck and good runs with it.

[NOTGSXR]

When are you coming to CT so you can run my boat lol

[Strokerdean]

RR, what jack plate are you running and why can't you raise the motor up a set of holes? Did moving the motor back from 8" to 10.5 make a difference in perf and handling? Congrats on the performance you and Tim are getting out of the 21 footers. It is refreshing to see others working to achieve the speed and performance. Keep up the good work. You need to make a call in NM and bring your boat down south and run it, you'll also be able to drive a diff brand that runs ok. It would be interesting to see how the elevation affects the 21 ftr.

[NOTGSXR]

You guys are amazing..

[River Rocket]

I believe skid planner looks the same as Tim's. It's just longer. It is concave in the center. I feel like I have seen a photo of one that looks different along the outer screw holes. Maybe that is the new one. I will post a photo of mine later. I'm making a new one that should work way better for how I use my boat. I would like to see photos of other versions. Maybe something I can barrow from.

I will also get some shots of the lower running in the water. My lower unit cone tip is about 1" out of the water while I'm running. You can see why my water pressure picks up at full trim. The inlets become inline with the water coming off the pad and it sprays right in. When its tucked in they are mostly out of the water.

I run the Allison hydraulic jackplate. you don't see many of them around. I also have 2" spacers. My motor is mounted at the top hole. Need a new jack plate to go up any more. Personally I like it because fast is all the way up. No need to watch the gauge. Just run it until it stops.

I would love to take yours for a run. I will be out in NM next month. I'm sure it will be too cold at that time. I will plan a spring trip and see if we can't get together.

[Strokerdean]

Another thing, I added one of Cbaily's hole shot plates a couple years ago. It makes a huge difference on hole shot, I can get out of the hole with my 32 uncut p4, 32 bc p3 and a 34 rl cut p3 (stock 300xs/1.62 sporty) where before I had to do donuts to work the rpm up enough to allow the motor to spin up. I also have a titanium foil on the LU.

[River Rocket]

Here is what I have for a setback and skid planner. the really close shot is the skid planner on Nathan's boat (I knew I saw one recently). He has the one I believe Notgsxr is referring to except it is cut flush with the transom.

I have studied the Baily holeshot plate several times. I would love to get one and support his business, but we don't have room for one. We technically run the same amount of setback as a stroker, but 40-50% of ours is built in with the pad so far forward. Baily gave me his end of pad to back of prop shaft number (at neutral trim) and I'm 2" farther back.

[River Rocket]

I just made a foil as well. I mounted it tonight. I'm excited to see how it changes things tomorrow. I was tempted to go titanium. It only figures that you did. I ended up going stainless. Unfortunately I stole the design from my 2.5L. The lower is thinner. I had to get the jig saw out and do some trimming today.......

[NOTGSXR]

My skid planer i s the same RR. Here is Powells...
IMG_20171027_42902.jpg

[Tim Powell]

Very interesting results.

[Strokerdean]

I have never measured from the pad to the prop shaft, I will do that today. What does your measure?

[Strokerdean]

With everything level, back of pad to back of prop shaft measures 59".

[River Rocket]

Dean are you running more setback than most?

[AllyFishing]

RR, your skid planer is the original long one with a straight back edge near the gearcase. Tim's (and mine are the same) is shorter and a slight concave cut area between the outer "flutes" (for lack of a better term)

go to this link and you will see the skid planer that is on Tim's boat. Your original skid planer is not shown on their website anymore. XB-21 skid planer (new style)
http://www.allisonboats.com/content/...nal-equipment/

Nathan has the original skid planer on his 2+2 unless he cut it off some or replaced it

[hooken203]

Here is a couple pictures of ones I have. The one on the left is what comes in my boat from the factory. The short one came off my last boat it was cut off even with the back of the boat. I put the short one on just to see what would happen when I had a 31 XOB on my boat that was cavitating bad on holeshot. Made my bow rise a lot more. Made my time to plane worse and did nothing for the cavitation.

[AllyFishing]

The shortest skid planer is the worst. The longest (original) is the best hole shot but as some high speed owners will attest to it's catching the water off the back edge if it's bit rough.

[River Rocket]

Thanks I see the difference now. Both outside edges (out bound of the outer screws) are bent down and the center is cut in a curved fashion towards the gearcase. Nathan has the outer bends but not the curved cut back.

[xb03fs]

Mine is cut flush with back of boat. 4.5” was removed. Kinda think I should have only removed 2”?