How much trim?

[MET]

Hey guys....

I know this is going to be a hard question to answer. I have an xb-21 2 seater with 300xs and 1.75’s. I have had the boat for about 3 years now, and have never really run it looking for a top end number. To be honest, part of the problem is that I am just a bit scared once I get over 80.

I have only had the 1.75’s in the case for a few months now, and really like the hole shot and midrange compared to the 1.62’s.

The biggest prop I own is a Robbie worked 28 Promax.

When I had the 1.62’s, I had the right water (which is very rare for where I fish) and ran it up to 90 mph for a short burst but didn’t pay attention to trim position.

I am trying to figure out a ballpark on the smartcraft gauge where I am reaching a dangerous trim position. I almost never trim up past 7.0 - 7.2 on the gauge. I keep reading about bumping the trim a notch to high and having bad things happen, so I get nervous. I can tell the boat really loosens up around 7.0. I think below 7.0 feels like I am still at neutral or slightly tucked.

For you guys running bigger numbers, where are you maxing out trim. I am around even to slightly under the pad.

Is this enough info to get any feedback? I don’t want to hit that trim switch a fraction too much and get a surprise.

I really need to get to one of the rally’s and let you guys with a lot more experience than I have drive this thing and let me learn. Until then, I am learning on my own.

Thanks for any advice....and Merry Christmas!!!

MET

[hooken203]

I think you should go through your basic set up. Zero your trim gauge. Measure you prop to pad and know where even with the pad is. At this time you can also figure out where neutral trim is. If you run transom wedges I would guess the neutral trim will be about 7.5 give or take .2. You should be able to run even with the pad and neutral trim all day long and never worry about a thing.

[AllyFishing]

Hooken hit the nail on the head. That's the first thing that went thru my mind is whether or not you are using the negative wedges. I would guess you are using them if you are trimming into low 7's on the gauge but like kevin stated be sure your gauge is calibrated. I firmly believe if you tap up a time or two past where you have been comfortable with the boat will tell you its too much by getting more squirrely to drive. Do everything Kevin stated first. Also check your water pressure. General rule of thumb is above 20 PSI is good.

I think too that with your 1.75 gears and a 28P Promax you will hit the limiter before you ever get in trouble. I bought a new 1.75 sporty mid summer and tested it while my 1.62 gearcase was getting re-sealed and I'll tell ya, with a 300 XS on the two seater it is wayyy more fun to drive with an awesome hole shot. I tested it with my 28 XOB and it was a rocket out of the hole.

[River Rocket]

Both said what I would have said on setup. The 28 should keep you at a pretty safe speed for trouble. The limiter would be my only safety concern when you hit it you will got your throttle chopped. I have done it a bunch with my 26 at mid 80's and the boat handles it very well. Just know that it will happen. If you run weedy lakes it will feel like you hit a patch of weeds.

Promax is a good safe prop. Mine starts to get iffy around 97. Steering goes above 97, but that is trimmed out and aired out. My big numbers come within 1 point above Neutral. I can run 95 at Neutral trim with my props that can go that fast.

With a heavy boat (tournament loaded) boat I can be very much out of balance to around 91/92 (that is 40-50lbs off on weight distribution). With a light boat that is low 80's (sounds weird but its true.). I don't run my boat over 90 without a full tournament load in it. The Prosport needs weight in my opinion.

The biggest point I would offer for high speed running is motor height. My boat, and the others that I run with all like the motor high. The boat handles very poor at high speeds if the motor is low (even or near even). It took me forever to figure this out. I was terrified to raise it after reading all the stuff on this forum. After I did, it made a huge difference in handling and speed. When running 8" of setback my motor always ran at 1/2" over. Even was bad and 3/8" was doing pretty good.

Hope this helps. Be safe and have fun.

[Johnny Maxwell]

Running safe is always better than running fast first and foremost. With that said, it would take a very short time with us at a rally to get you rolling big numbers and do it safely. 1/2” high above the pad is high enough for me. Def have to know what neutral trim is on your setup. On my best runs I’ve run 8 to 9 on trim. I had wedges on the last 2 boats. Not the new one. Negative to your setup could be 7.5. I have to think you could run 8 or more balanced and with some good water.

[Tim Powell]

Stock 8" setback plus wedge = 7.4 - 7.6 neutral trim, 8.4 at WOT

Stock 8" setback without wedge = 6.4 - 6.6 neutral trim, 7.4 at WOT


To make a WOT run, your gonna need a much bigger prop. You will kill the limiter with a 28 promax and 1.75 gears. IMO the boat will be very hard to prop with 1.75s.

I spun a 28 promax to 94.xx at the limiter in 100 degree air solo loaded to fish on 1.62's with stock 300xs.

[MET]

Thanks for all of the responses. I am not trying to make a high speed WOT run. I do know I will need a bigger prop at some point, just haven’t gotten it yet. I still have the 1.62’s if I ever want to go back.

I very rarely if ever have the water conditions or room to really stretch it out. I also don’t have the experience or confidence yet to do it. I was mainly concerned with trying to determine neutral trim. I do have wedges and standard 8” setback.

Thanks for all of the valuable advice guys.

I am definitely going to get to a rally one of these days.....would be a great place for some hands on experience with way more seasoned drivers than I!!

Thanks again for the advice...

[Tim Powell]

The boat will tell you when it's had enough trim. Just feel what she is telling you.

[xb03fs]

The boat will tell you when it's had enough trim. Just feel what she is telling you.

X2. She usually gives you time to correct too much trim as well.. unless you ignore and bump it a few more times

[AllyFishing]

The boat will tell you when it's had enough trim. Just feel what she is telling you.

"Feel the Force Luke!!"

what RR stated about the limiter too. I've had my kill switch pull several times over 80+ MPH and it just settled down straight.

[wbh1954]

Just Hammer On It :)

[xb03fs]

I hit a roller at 90 and had to come completly out of throttle last fall and boat stayed straight made me feel pretty good.

[Johnny Maxwell]

If I hit a roller at anything above 80 and let out of it, there will be some very interesting driving involved for the next few seconds. LOL. Was the same on my other 2 Allison's as well. BassPort Pro's only? Maybe. I can't speak for the ProSports. I am guessing BassPort Pro's and 2+2's are the same way on a fuel drop.

[xb03fs]

I was lucky. Hit it perfectly perpendicular. It was near an entrance to a harbor which is why I never seen the source likely, as boat probably went in. I cannot remember if I chopped throttle or backed out slowly or what it happened so fast I just relied on instincts.

I went slow back to trailer and was very thankful.

[Tim Powell]

I slung a blade in the 90s and pulling hard, other than the motor sounding like it was about to rattle apart the hull didn't do anything stupid, she just sat back down easy.