XB21 setup and props I got with the boat

[twsykes]

Bought a 2012 XB 21 sport master gear case 250 ProXS and I Just getting everything setup now... I ran it up to about 75 yesterday but that was with the hydraulic plate at 1/4 up and trimmed on the engine to about 4.2. Did not seem like it had much left honestly but I figured I would check with the experts here to see what you guys say I should have and be running. Looks like the guy was running 26P props the the ET lighting the one I was running yesterday at 75MPH. Running a 26 P RH Lab ET Lightning 48-8M0006666 and he gave me a Turbo TXP-OT4 26P as well. Right now it just seems odd that this guy was running a 26 prop on a 250 Pro XS on a XB21? Am I thinking right here? He also has a hydrofoil on it and the metal bracket on the pad from allison. Whatever that is called.

So I want to run as fast as possible but don't want to come out of the terribly slow and want to be as safe as possible. What are you guys thoughts on the right way to set this up and what your thoughts are? It sure seems that 75MPH is pretty slow for this boat and that a 26 is not enough prop for an Allison for sure

1. what props are recommended for the XB21?
2. where the sport master be in relation to the bottom at Wide open throttle?
3. engine trim?

Thanks guys!

 

[scj]

I'm guessing you have 1.62 gears; if so, a 27 Bravo, ProMax or Hydromotive would be starting props I'd use.

Not sure about your setup but 4.2 on trim seems pretty tucked under. A good way to go around pushing the nose down at 75 mph......
Usually neutral trim on these is somewhere around 7. That's as flat as you should run an Allison at speed. If neutral is 7, then you can safely run to about 8 on the trim gauge.

It's best to level the pad and prop to know what's neutral though. Not something I'd guess at on an unfamiliar boat.

A 1/4" over pad is a good starting point as long as you don't have a transducer laying out in front of your engine disrupting water flow

 

[GotMyAlly]

What did your RPMs look like?

I'd drop the engine some to start. Put it about 1/2" under the pad. Work your way up from there. There have been some boats over the years that ran higher, and some that ran lower. My 2012 does not like to run above the pad. My previous 2008 boat would run 1/2" over the pad any day of the week. Something changed on the manufacturing end? We'll never know. I understand some of the newer ones like the motor height above the pad again, more like the 1st gen boats.

As was said above, sounds like you were tucked under, assuming your trim gauge is calibrated correctly. I'd expect any 26" prop to hit the rev limiter pretty hard. If you have 1.62 gears. you'll probably want a 27" or a 28" prop for carrying a fishing load, depending on how much tackle you carry. The 27" will have a stronger holeshot and mid range but give up 1-2 mph on the top end. If you're running light, you can bump up to a 29" or 30".

 

[Bobalouie]

A lightning ET on a XB21? That does not sound like a good combo at all. A small barrel prop is not going to have the lift that an XB21 is going to need. Look for large barrel props like the ones stated above.

 

[twsykes]

Just curious. What should I realistically look for about of this boat speed wise? Its a XB 21 with a 250 Proxs with a sport master. It does have power poles on it tho.. I just want to know where i am at realistically. I am going to check the pad settings and everything today so I will really know where the trim is etc....

 

[GotMyAlly]

I don't have poles, so I'm just guessing at what they might scrub off, and it really depends on how big a boy are ya and how much tackle you carry....but I bet it'll fish upper 80s and knocking on the door of 90.

 

[twsykes]

I weight bout 180 and pretty conscious about weight. you seem very knowledgeable so a couple more questions?

1. should the tackle be put in the back bins or up front?
2. If I have a partner he would like be 200 plus so would I move weight around if he is in the boat to keep it balance"
   
3. what would the perfect balance for this boat be curiously enough? front to back?
   

Thanks so much BTW

 

[GotMyAlly]

Some of the front to back weight balance questions will depend on which boat you have......ProSport, BassSport Pro, or 2+2. And where you're batteries are located.

The boat has plenty of bow lift to carry your tackle up front. Obviously things like anchors and spare props should go in the back of the boat. For ease of driving, left-right balance is more critical. You'll want to be slightly left-side heavy at rest. It'll level out over 80 mph. You can move your stuff around to accommodate for a lot of that, but a 25lb bag of shot is invaluable for fine-tuning the balance.

 

[Tim Powell]

All good advise above.

One thing I would recommend is removing the foil.

 

[twsykes]

All good advise above.

One thing I would recommend is removing the foil.

Interesting that you say that. I wondered why he had it on. I trust your knowledge just curious cause I wondered why he had it on in the first place. Your boat picture looks just like my boat Btw.

Here is the engine and the back of my boat. I am wondering what the metal plate is in the back behind the pad and you can see the foil there too.

One interesting note. Today I ran the boat with the lightening prop (26) as picture and played just a tick to get to know the boat a little. I have ran high performance boats before where I had to drive thru the chine walk but those boats only ran around 75 max. What's interesting to me is this boat seems to run 75 with the boat flat without the rat tap tap that you usually hear when the only thing in the water is the pad so today I tested just a little as I trimmed up to around 7 as mentioned above and the rat tap tap started meaning I was on the pad but the boat began to chine walk but I could certainly feel it start to free up and approach 5800 or so. thanks for all the help guys.

 

[Tim Powell]

The aluminum plate under the boat is the skid planer. It was installed by the factory and is standard on the XB-21. It is basically just a pad extension to help with slower speeds.

Do you happen to have a LSS transducer mounted under the Skid Planer? If so, remove the transducer from the skid planer.


In my testing, I have found the foil to cause handling issues and slow the boat down 6 mph. That shouldn't be the case but it happened on my boat. I installed the foil in the fall and didn't do much hard running over the winter but when I did I noticed the boat was a handful at 92 and seemed to hit a wall. Before installing the foil I had ran 98 several times with the same load. Come spring I started running more and couldn't get the boat past 92 to save my life. Then it hit me, the only change was the foil so I pulled it off and made a pass at 98 and the boat was a joy to drive.

I will say, this was with a Hydromotive X-O/B and I believe the issue was caused by the way water comes off the flare and caused drag once it hit the foil.

 

[twsykes]

Quick update:

Recap: XB21 Basport pro elite 250 pro XS with sportmaster 1.62 gears I just bought: working on the setup

I checked the pad verses the prop centerline and found that when the CMC jack plate was all the way up the pad is about even. Not sure if that is normal or not?

Here is what I did afterwards:

1. I put the Jack plate a little less than all the way up which put the propshaft about 1/2-1 inch below the pad and just left it there
2. I put the trim to about 2.o to come out of the hole and left it there as the starting point for trim (any more than 2.0 out of the hole and the prop seemed to start slipping as the bow fell when coming out of the hole)
3. I swapped out the prop to the Turbo TXP-OT4 26P instead of a lighting ET 26P which was the other prop I got with the boat
4. I move my fishing boxes to the left rear compartment for more balance

It was interesting that I was able to get the boat to run 80-81 at WOT (verse 75 with the lighting et 26) but did not have enough water to stretch it out even more. I had a full tank of gas with just me in the boat (I weight about 180) so it was not a huge load but for the first time the boat seemed very stable and I can see that it will roll if I just fine tune it more. I wish I would have had more room to stretch it out but I did not..

I kept trying to see what the RPMS were but I could not stretch it out enough to see if it would still climb up.. At this point the hole shot was good and the RPMS seemed to be around 5600-5800 but like I said I really could not stretch it out more as I ran out of room

Anything seem odd about the above? I also noticed the steering seemed pretty hard at top speed which seems to me that somethings not quite right?

Anyone see anything in the setups that seems odd? Thanks guys..

 

[scj]

You're flirting with disaster I'm afraid; I think the only thing keeping you spinning the boat around is your rear end weight.
First things first; looks as if your engine is set one set of holes too low. Probably a good thing for you with the poor choice of props someone sent with the boat. Sell those to someone running a 20' speed down. Buy a 27" Bravo for a good all around prop.
You don't need to run your engine below pad with power poles.
Since it's set too low anyway, you're never going to get all it has to offer until that is corrected.

Let's see if I can explain this clearly enough.......the way your boat is setup and the props you're running has your boat wallowing through the water setting way to low for high speed or efficiency. But, it's not chine walking which is something you're going to have to learn to deal with on an Allison if you want to run it to it's potential.
When the boat runs flat, like you describe, it's pushing the nose down which allows you to run upper 70's without fighting the chine. Problem with this is the back of the boat is wanting to push up out of the water. Since neither of the props you have are made to carry a boat that size, you've been able get away with wallowing along pushing a bunch a water. Your luck is going to run out and you're going to swap ends pushing a poorly set up boat.......

As I mentioned in my first post, you should never run any speed 60+ mph with the engine less than neutral trim. You're asking for trouble. What happens is the rear of the boat is trying to pop out of the water.

Get the right prop. Set the engine even with the pad. Balance the boat side to side depending on one or two aboard which means you may have to add ballast to run solo. Get out on the lake/river and learn to drive through the chine. Keep the trim just over neutral, tapping it up frees the boat up which you will feel.
Plowing the nose is not safe and it's not how to achieve speed or efficiency.

 

[twsykes]

Thank you for the reply. I should have told you this but forgot to. With the CMC plate almost to the top (the prop shaft about 1/2 below pad) and trim set at 2.0 when sitting) as I take off I do begin trimming the boat out and end up getting it to about 4.5. Anything over the 4.5 and the boat starts to chine walk but I honestly have not had enough room to drive thru it because I have been running out of lake... So whats the protocol when the chine starts on these boats? I use to have an SP200 procraft prototype that was built after the ally hull and I had to driver the heck out of that boat but it was an early 70s boat at best. When it started to chine I would kinda pop the wheel to keep it on the pad well. What should I expect out of this hull? What should I be looking for exactly and what I should I do when I see it?

Sorry for so many questions here but I don't have anyone around me with an Ally so the help in invaluable from you guys! Thanks!

 

[twsykes]

Also, Tim. You mentioned removing the foil (I will do that) and you mentioned removing the Transducer on the skid planner. Is there a place you would recommend? Thanks

 

[scj]

The foil is not going to hurt you until you get into the 90's.

You need to level the pad of your boat and level the prop shaft to know exactly where neutral trim is. At the same time, check for pad to prop height.
Knowing these settings helps your learning curve. Mostly so you play it safe while learning to drive your boat.

If you're waiting to see your boat chine, you're too late. It's something you have to get a feel for. You know it's going to happen so you have to anticipate and get your timing correct.

 

[scj]

 

[twsykes]

will do and thanks again. Where did you get that bracket from Allison? Thanks Tim

 

[twsykes]

will do and thanks again. Where did you get that bracket from Allison? Thanks Tim

Ok, did some more checking today and went out and played a bit as well and checked the measurements more closely:

1. To the pad I have 16 3/4 from the floor when level & to the prop shaft center I have 17 1/8 (with the cmc all the way up) basically enough to run a little less than 1/2 above the pad if I need to. not sure if this is enough or not? Do you typically run props higher than 1/2 above the pad?
2. Today I ran 82.5 light load with the Turbo TXP-OT4 26P (I know I am going to get some props soon) I think at this speed the prop shaft was even with the pad if my calculations are right. Today that 82.5 was at 5.1 on trim (More on that in a 2nd) and about even on the pad or close. I was beginning to inch it up on the CMC...
3. The odd thing is I still seem to be about 5600 on RPM I think. Is that because the motor is still not high enough?

So I found something a little odd when looking at pad height and Engine height all the way up on the CMC. I was messing with the Trim for/aft and noticed that when I put the trim all the way down the gauge got to zero but I still had about an inch of trim left to tuck the motor fully. I assume that the trim indicator on the motor needs to be adjusted so when fully closed it is a zero? Am I correct? This might be why it seems by the numbers 4.0 and 5.1 that I would be plowing. I don't the sensor is adjusted right


Also this might be a silly question but what is actually neutral trim? Thanks guys

 

[scj]

Notice the laser level light showing the prop shaft level and the pad of the boat level as well. That's neutral trim position and prop even with the pad.