Torque Lean
 

03 tremor close bow, - 25 foot boat
re freshen the motor last winter
new motor is got a ton more power but anything over 60-70% throttle and accelerating it rolls pretty hard

merc ITS with a bravo 1 XR 1.5 ratio, standard length leg - not sure on prop dept in relation to the bottom of the hull

currently running a stock RH 28P bravo, rolls hard to port - moved weight around and makes no diffrence

ran a labbed bravo 1 LH 30, rolls just as hard to starboard and the exact same top speed.

cant trim up out of the roll as it puts the boat into a pretty good porpoise

any ideas?

I have this very same problem on my 28 heat...I can trim up and throttle through it but mid range cruising is baadddd....I installed 280 kplanes as part of my rebuild and I have to drag the port tab at like 4-5 on the indicator and it pops up level like nothing happened....not sure if tabs are an option for you or not?

I have also heard that switching to a LH prop and obviously switching your shifter helps with the roll but I can't speak from experience on that

Good luck!!

has 24' tabs on it, they can correct it but running wide open it scrubs a ton of speed and im not down with that haha, tried the left hand, just made it lean on the starboard side

im 96% sure its drive line torque and ist just rolling the boat but i have no idea how to fix it, change gear ration?
shorty drive to lessen the leverage point?
do a surface drive? haha

I hear ya on scrubbing speed....obviously different boats but I have a shorty on mine and it made no difference on the lean....that's all I got lol

Does it do it with the drive all the way tucked in? I know mine does it worse when I'm trimmed out...Also if its a pad boat you may be right at the point of falling off the pad making the lean much worse..have you tried the ole steering wheel flick and see if it will jump up on the pad and correct itself? Just a thought maybe??

the its has a setback to it. With a standard lower your prop is now even deeper. so a big prop not only pushes the boat forward, it also turn the drive into a lever resulting in the lean. try borrowing a shorty lower. also if your still running a 3 blade try a 4 blade prop.

no pad, its a single step v hull 24* V, small step - maybe 1-2 inches deep

been trying all 4 blade props
little to no diffrence on the lean between zero trim and its happy area when cursing, to much trim it just purposes

do you think its a diameter or the pitch that shows this effect more?
like staying with a 28p but going to a 15 or 14.75" diameter should lessen the roll?

Just a thought

Maybe try a 3 blade to reduce the lift. Boat is out of the water like a bass boat, but weight is much greater

i dont think the lift is the issue unless im missing something

if anything i feel like if i could get more lift with less trim it may let it flatten out and not purpose

I doubt that you have the HP to cause the lean.
I would say it is your drive depth. when You go back you have to go up.
borrow a shortie and see - it should help.

i didnt think it should either but i cant find many "smaller" boats that are a v hull and in the 800hp range -
it left the factory with the ITS set up and stock it ran super flat. only big change is the power, and maybe some weight

what is considered a "deep" drive

At the same speed as before you changed the HP does it act the same?
If no than it is something else you changed.
If yes than it may be because you are going faster.
Some boat hulls are designed for a certain speed and above that speed the hull becomes unstable.
with a non pad bottom the faster you go the higher the boat rides in the water. The higher it rides the more it wants to lay over.
try a three blade prop for less transom lift.
also bigger diameter props cause transom lift.
You could also try cutting the bell off the back of your existing prop. That will settle the transom but WILL make the boat harder to get on plane. This is a cheap fix - I would try this first.
none of my props have the bell. Cats DON'T like transom lift.

it acts the same at speed till you really crack it open,
it doesn't feel unstable, like it doesn't feel loose or like it wants to swap ends or like its fighting anything. just laying over haha

got the big ass tabs so ill give that bell cut a shot,

this is a newb question. but would stern lift cause it to lay over or just extenuate the problem

Stern lift can cause it to lay over.
With some hulls the faster you go the more it wants to lay over. The boat is riding higher and becomes less stable.
Your hull has a design top speed and you may be exceeding that speed.

You need to stagger your tab settings. If your boat lists to port, lower the starboard tab until you level the boat. As your boat speed increases and your boat cleans up you can raise the tab until the listing starts again. Then re-level the boat. The listing will be worse when you drive slow. Seat time and tabs will take care of this problem. You may or may not have a problem at high speeds. If the boat flails off the pad, you will start chine walking. ( boat leans to one side and then leans to the other side ). Chine walking can be dangerous if you allow your boat to continue to rock back and forth and the speed and degree of the rocking continues to get worse. At that time you have several choices you can make. You can drive through this if you can counter the rocking with your steering. You can slow down. Or you can start gradually putting your tabs down. The counter steering takes some practice and it is helpful to have an experienced captain to coach you as you drive. And some boats can’t be fixed until your hull bottom is leveled ( blueprinting your hull ). Do not practice the high speed chine walking with a boat full of passengers. The low speed leveling is fine to practice with passengers on board.

You can move weight in your boat to the high side and you can also arrange your passengers so that the most of their weight goes to the high side.

The main thing that you need is seat time and maybe some pointers from a more experienced captain.

at low speed and normal speeds it runs flat, any list can be cleared up with a little positive trim.
no pad on the boat 24V step hull v all the way back.

not to be a turd as i do appreciate the help but most of this has been covered

it leans when i accelerate hard past the 75mph mark, swapped props to a left hand and t leans the other way. cursing it runs flat with zero issue, its only when i punch it the boat lays over.

prop dept is 4.75" not accounting for the ITS setback, what is the rule of thumb for setback?

i feel this is pretty normal depth for a transom mount but not sure how the set back effects it, it never throws any kind of roost or spray when trimmed up

If you throttle up slow does it still lean? You say punch it and I'm wondering if it is indeed the torque of the motor and if it will level off once you get through the torque band? I noticed on mine after running more that the faster I go and the more I trim it the flatter it gets and I can pull the port tab up and it will stay level

I have always heard that a different gear ratio and smaller prop was usually the cure for torque lean.

Padraig

honestly BBYSTWY i never tried going in small increments, got it to 70 or so and get it set up to run and just lay into it - been breaking in a new motor and trying to sort out props and dont have a lot of room to run haha. ill have to try in the spring going in 500rpm bumps and see how it does. i cant trim out of it sadly boat gets to unstable with more trim - into the porpoise area.


Padraig, ive thought about this but i cant seem to get any real info on how this effects torque leverage? from what ive found a lot of cats/ semi surfacing drives do this. but with being a V hull and a relatively mild prop depth i cant find much info on it

Quote

Padraig, ive thought about this but i cant seem to get any real info on how this effects torque leverage? from what ive found a lot of cats/ semi surfacing drives do this. but with being a V hull and a relatively mild prop depth i cant find much info on it[/QUOTE]

I too have no real world experience with it but back in the late 90s many vee a hulls were being supercharged and the owners were just going up in pitch and would often experience problems. The recommendation was usually was a gear change instead of a bigger prop.

I would give BBlades a shout out.

Padraig

I too have no real world experience with it but back in the late 90s many vee a hulls were being supercharged and the owners were just going up in pitch and would often experience problems. The recommendation was usually was a gear change instead of a bigger prop.

I would give BBlades a shout out.

Padraig[/QUOTE]


ill have to do some more reading

i did reach out to BBlades and he sounded pretty sure with some prop work he could get it pretty cleaned up, so ill be sending that out in a few week s

Do you remember if it was a pitch or a larger diameter thing ? I know diameter can do some odd things, especially small lightweight boats.

I was wondering if its a diameter thing as well, if you have less of it, it should be less leverage to roll the boat - or so i thought but i could not find any info on it

If no answers here, being a West Coast Boat, there are a handful of those Shockwave Tremor's running pretty good over at River Dave's Place.
Here is just one thread: https://www.riverdavesplace.com/foru...tremor.101747/

did some digging on their, a couple with 565's but not much more in the wood works it seems

Dont know if it would help but I read an article years back about a little tab you can put on the length of your skeg to prevent torque lean. RPM used it on almost all their boats.

RPM? The cats being built by Lavey?

I wonder what it was or called I'll have to do some digging I know about a wedge on the skeg to avoid crap walking when running fast In a single eng boat but neve came across one for lean

https://thmarinesupplies.com/products/torque-tab
Torque tab, but as you said, believe to counter torque steer. Never read or have any experience if they help with a list.

Cant seem to find any info on the list/torque lean.

For $26 its worth a try. It cant get any cheaper or easier. It will cost more for the beer.

I wouldn't do it

i cant find any info on how it may help so im going to avoid it, im leaning towards the drive height, figure itll be the same trimming up the drive and with it being shorter it may help

Whats the beam on your boat? I had a bunch of hp in a Baja 272. It was pretty flat with labbed 28/30s and 32's, it had a little tq lean when I ran non labbed 4 blades, tried a couple 5 blades and boat would roll over under hard throttle to where rub rail was in water.. 7.5" prop depth. Prob with dragging the tabs like mentioned and Im sure you already know this is the minute you back off the throttle boat does evil **** in opposite direction. A friend had a 24 sunsation, he always had to drag a tab (narrower beam) above 65, when he tried to run 4 blades boat torque leaned sideways. With 800 hp I dont see you having ANY chance of running a 3 blade, Smitty

98" according to the builders website
i only tried dragging the tab once, besides the total lack of speed it was not fun on the off throttle haha

i was wondering how a clever style acts in difference to a normal bravo prop. not worried about getting on plane if thats the big trade off

i had a 1986 nova spyder , with twin 330hps, boat rolled hard to STBD side, i would correct by trimming drives. LTZ your trim tabs wont offset the roll or pull??
my machine shop owner years ago , ran a 25 checkmate with a 468 . boat ran mid 70s. i ask him about the roll or pull from torques, he said he ran a LH drive.

no pull, just the lean.

trimming works up to about 70, past that i dont play with the trim, ran it at 75mph and played with it, started to porpoises before it would level out so i gave up.

tab can take it out but it scrubs so much speed i might as well just run slower haha.

tried a left hand, just tilts the other way with the same issue

wow......hmmmmmm,,,,sorry to hear
PROP ???? try different style??

Been trying bravo 4 blades. Going to send one to blades and get him to work it over and see if we can get it sorted

Right hand prop lean starboard, left hand prop lean port, B3 lower maybe :party-smiley-004: