21ft Bass Tracker Pontoon question

[Whiteriver]

My neighbor has a 21 ft Bass Tracker pontoon with the extra toon in the middle that only runs about a quarter length of the boat.. I guess it's just for motor support or the likes.  The transom is mounted above it and he has 60 hp Merc Bigfoot mounted on it.  His problem is that the motor seems to be cavitating and the prop isn't getting a bite and the rpm's are rapping up there.  It is at low, med. and full throttle that it does this, so I'm guessing it's not catching enough clean water and maybe an air pocket is forming due to the extra pontoon in the middle.  Bass Pro's people said it should run in the second hole, but it doesn't and he even lowered it a hole or two and still has the same problem, except it really torques when it's lowered.  He's also changed props a couple of times---from a 15 pitch to 10 and it didn't help.  Also, he said that when running in choppy water it will grab a bite every now and then.  Anyone have any idea what might be going on here and possibly some advice?  It would be greatly appreciated.  Thanks.

[fishinwrench]

Can you post a pic or two? (Preferably from the rear)   If I could get a look at the rigging setup I might have some ideas.   

Have you pulled all of the drains to be sure none of the toons are heavy with water?  

[Whiteriver]

9 hours ago, fishinwrench said:

Can you post a pic or two? (Preferably from the rear)   If I could get a look at the rigging setup I might have some ideas.   

Have you pulled all of the drains to be sure none of the toons are heavy with water?  

I will get a couple of pictures.  He was explaining what his set up was and I really hadn't paid much attention to it in the past, so I went over there last night to take a closer look.  It's a 2012 setup and the motor has tilt and trim.  He has a 20ft Bass Cat, so he understands the motor needs to be trimmed all the way down on take off.  We put a straight edge on the motor and it was about 4.5 inches below the planing toon or whatever the official name for the middle toon/planing apparatus is called, so we raised the motor another couple of holes and now its about 1.5 inches between the planing toon and the cavitation plate on the motor, but that's the last hole, so it can't be raised any further.  He also changed the prop back to the original 3 blade 10 pitch that was on it.  He keeps it trailered and in a garage, but I will have him check for water in the pontoons---he's taking it to the lake today to see if raising the motor and the 10 pitch prop helped--the 15 pitch is not a pontoon prop I don't think from looking at the specs--especially for that Bigfoot motor.  I'll snap a couple of pictures when he gets back from the lake.  Thanks again.

[Smalls21]

what year of boat is it?

also pictures would be nice, it is easier for me to give advice if i can see what i'm looking for.

what kind of prop? alum/stainless 3 blade? 4 blade?

[fishinwrench]

I would expect it to turn a 15p or 17p prop. 

Most 24' toons with 115hp outboards will turn a 19p prop of the same diameter.

With the motor basically level (no negative trim) have him try slowly accelerating from a dead drift and note at what RPM it begins to blow out.   Then have him "nail it" from a dead drift and see if it blows out earlier or at the same RPM it did during gradual acceleration.    A toon has no "pad" to get up on so tucking the motor in for a hole shot really doesn't work.  Once you find the trim angle that eliminates plowing and causes the steering to be as near to effortless as possible then that is the correct trim angle for the day..... don't touch the trim switch again unless passengers move around or the load changes. 

[Smalls21]

for a 2012 party barge 20 or 22(cause they did not make a 21ft boat in 2012) with a 60hp big foot engine, it should be mounted 3/4" above the transom, and

should have a 14x11P prop

[fishinwrench]

Is it like this one?

[Whiteriver]

He's still at the lake, but called me and said changing the 15 pitch Stainless back to the 10 pitch Aluminum didn't make any difference.  It is blowing out at around 3000 to 3200 rpm's with both props.  Both are 3 blade.  And, I it's a 22ft Tracker Fishing Barge, but it does have a 60 hp Merc w/tilt & trim.  As soon as he gets back I'll take some pictures from the back of the boat.

[Whiteriver]

21 hours ago, Smalls21 said:

for a 2012 party barge 20 or 22(cause they did not make a 21ft boat in 2012) with a 60hp big foot engine, it should be mounted 3/4" above the transom, and

should have a 14x11P prop

It is a 22 ft Tracker Fishing Barge w/60hp Bigfoot---he changed the 15 pitch 3 blade to the 10 pitch 3 blade and it still blows out at approx 3,000-3,200 rpm's.

[Whiteriver]

Update on this situation::::::  He changed props to a 10 pitch 4 blade and it fixed it---no blow out and getting plenty of bite.