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Austin
30-04-2014, 04:53 PM
Hi Guys,

Just a quick question to sound out your knowledge on what could be the possible cause of my hull listing slightly to port whilst underway.

It's a new model Stacer Baymaster 489 running a Yamaha F70. A sweet set up that does just about everything right for trout trolling on the snowy lakes. It has the Evo advance hull which handles pretty well..... apart from a small but definitely noticeable lean to port when up and running that I noticed from first time out. It was a bit disconcerting a first as the boat seemed to be balanced well with weight distribution and trimmed correctly etc

It was water tested prior to delivery with no reported faults or unusual "traits". I had my first 20hr engine service back in Feb and reported the issue to the dealer (as you would) assuming it may be something to do with trim tab adjustment etc. The tech gave me a rather vague answer about tourque of the prop causing a lean which seems to happen "occassionally" due to the hull bottom characteristics/design of the Stacer evo advance??. Too technical for me I'm afraid but the upshot (per the mechanic) was that there is no solution?.

Does anyone know of this from experience or perhaps anecdotally from other Stacer owners?. Thanks in advance for any simple technical explanation that I can understand.

stue2
30-04-2014, 07:18 PM
Prop torque happens to most boats except twins with counter rotating motors. You will probably have the eski behind the skipper and what ever else you need to balance your boat.
Tabs will fix the problem but so can your mate by standing slightly to starboard.
Cheers
Stu

gofishin
30-04-2014, 10:07 PM
... there is no solution?....
There is always a solution, but this involves someone's time and/or money! Finding the cause will obviously be a big help, but there can be many reasons, and sometimes the cause can't easily be fixed, but the lean/list can be rectified by other means.

Prop torque from a std RH rotation outboard will cause any boat to 'want to' list to port a little, some more than others, and especially lighter hulls. However, many other things cause lighter hulls to want to list too.

Go to the advanced search function and look for any of; lean, leaning, list, hog, hook, rocker etc... You should find heaps of threads and hours of reading.

I assume that static balance is perfect? Does the list change with motor trim? Or speed while planing? How much are we talking, in cm's etc.

Check the simple things first which all can help prop torque cause a 'more noticeable' list; transducer or LBT pickup on STB side - or anything else that might kick this side up, motor height, steering tab position... etc

After this it gets a little more difficult, as it involves hull shape. One easy thing to check 'by eye' is to make sure the keel extrusion is dead straight.
Cheers


Sent from my iPhone using Tapatalk

Noelm
01-05-2014, 07:47 AM
I don't think it is going to be any sort of twist in the hull (but not impossible of course) I think it is more likely a weight distribution problem, or the setup needs some adjustment by the dealer.

stang69
01-05-2014, 08:24 AM
defnitely prop torque. Those Yamaha 70's swing a large diameter prop for a small motor which doesnt help.
Weight distribution can help, like moving batteries to starboard side etc. (dealer should already have fitted them there I hope.)

fisho64
03-05-2014, 12:11 PM
without a doubt its prop torque as said above.
All of that 70hp applies itself to the water in a twisting motion (prop) and all motion causes an equal and opposite reaction.
On my boat I have a similar problem which annoyed the shit out of me.
Tried moving one of the batteries to stb but the stationary list was a pain in the ass, looked shit and harder to get on the trailer
So rather than fitting trim tabs which get in the way of the ladder etc, I made a wedge shape out of ply about 10" x 10" and about 15mm at the thick part.
Stuck it under the portside stern close to chine with a couple of dollops of Sika.
Gave it a testrun and it was slightly too much so trimmed it off and laminated one with glass/foam a little less wedge and stick it in place with sika, works a treat.
Boat floats level and planes level as well plus you can cut it off easy later if wanted with no damage or holes drilled
Drop me a message if you want some pics

Fed
03-05-2014, 12:43 PM
A 10"x10" trim tab on one side?
Gotta be a gee up, no bites here.

Austin, we need some feedback to help you.

I assume that static balance is perfect? Does the list change with motor trim? Or speed while planing? How much are we talking, in cm's etc.

+ Do you have no feedback steering?

tunaticer
03-05-2014, 04:02 PM
Have a look under the hull just where the hull flattens out behind the bow. One side might have landed heavily on a wave and been pushed in a tad....this will always give a list to one side as mentioned.
It only takes 3-5mm difference from one side to the other to become apparent as you are driving.

bdm56
03-05-2014, 09:09 PM
Don't know if this relative to your motor but on most motors the anode under the cav plate is able to be loosened and turned to offset prop torque. Might help.

fisho64
04-05-2014, 03:08 AM
A 10"x10" trim tab on one side? Gotta be a gee up, no bites here. maybe need to read it again mate. Trim tab?::)

deckie
04-05-2014, 08:48 AM
After a full refit/resto where i kept a complete track of any weight changes left/right/fwd/aft and had an F70A put on the back..the very first water test gave me...guess what...a slight lean to port when i was planing above about 35-40kph (4.8m glass rig) I was a bit disappointed thinking i had the weights somehow wrong, but later that day i assumed it was prop torque and wasnt overly concerned...mainly coz i had the 60l moveable livey tank i made up onboard and when i moved some ballast the lean went away....when i was solo..nothing..with one passenger i noticed the slight lean...when he moved to stand centre rather than in pass seat it corrected. So it was simply an easy fix for me with ballast...when alone 50ltrs of water is carried in centre down back.....when 1 other onboard 50ltrs water carried under or behind helm seat to compensate. I have never even bothered to actually seek out the real reason coz it simply isnt an issue. I thought i could correct by moving one of the batteries...i.e. take 30kg off port side and add the 30kg to stbd = 60kg shift...but havent even bothered doing that. To me just about all boats have little irks and quirks u simply compensate for and rapidly becomes a habit. I'm left thinking its probably just a bit of a torque/prop thing coz they do seem a largish prop. Luv the donk and performance and this simply wasnt an issue for me...BUT i'm damn curious now what others are thinking.

One more thing i would check on though...do you find the effect is more when u are up on the plane ? rather than any effect getting out of the hole ?

A lean to port is a very common issue with many well known brands and seems almost a random thing....especially around the 4.7-5.5m size. There is an effect (i forget the exact name of it) involving the wind (hope someone out there knows it and what its called)...and it inevitably causes a lean to port...VERY common and well known to the guys with trailer rigs on Port Phillip Bay for instance but doesnt often get mentioned in the usual "ramp talk" here in Sydney or up in Qld.

It involves the wind hitting on the Port side of the boat whilst up on the plane...has the effect of forcing the port side down somehow. When it was mentioned to me i suddenly noticed any slight lean WAS actually increased when heading slightly into wind whilst on the plane with it hitting the port side. Sounds a bit bizzarre but i;m hoping someone else in here knows what i;m talking about so i dont sound like a bit of a goose for even mentioning it.

I'd also guess its a bit of prop torque...my F70A does have a fairly sizeable prop so i assume thats all it is...but at least have a think...does it seem to happen mainly whilst up on the plane or getting out of the hole ? I'd investigate other issues and not restrict it to the prop. Check if particular wind directions seem to reduce it or make it noticeable. Just a thought.

I'd also add to the list the thought it might be a poor job mounting the engine. Just another possible worth checking out,.

Weird though...these modern tinnies around 4.7-5m are so incredibly beamy/stable, and dont have much side profile exposed to the wind that its hard to imagine what else it could be other than a bit of prop effect or at worst..an uneven/hook hull. They dont draw much and have little bite into the water, so i just thought i;d at east raise that wind effect to port as a "down the list" possibility that we know DOES happen to at least some rigs.

if it was me..i;d take her down at a non busy time and hammer it out of the hole with the steering dead centre and hands only resting lightly on the wheel...experiment with weight...experiment to see if trimming in and out changes anything...and take note of conditions such as breeze and chop direction to try to narrow it down to WHEN it seems most noticeable..otherwise can be a time consuming process. i.e. gather a few clues first.
Either way i wouldnt let it sour any thoughts on your new rig...pretty common thing and you'll get to the bottom of it.

Noelm
04-05-2014, 01:23 PM
It's not the wind that forces one side down, it is the fact that you have to turn into the wind to keep a straight course, THAT is what causes the lean, happens everywhere, Port Philip wind is no different to Sydney wind..... But then, there is that dreaded NQ chop that no boat can survive!

scottar
04-05-2014, 03:34 PM
Quickest solution if they don't cause any issues or break the piggy bank - a set of trim tabs. I fitted a set to my Victory to try and correct a different issue and now would not own a trailerboat with out them. Not only will they correct your list but you will be able to get the bow down at a lower speed in rough conditions which is a godsend in a tinnie. It also means you dont have to yell at your mates when they decide to wander around the cockpit while underway

Austin
04-05-2014, 06:46 PM
A 10"x10" trim tab on one side?
Gotta be a gee up, no bites here.

Austin, we need some feedback to help you.


+ Do you have no feedback steering?

Guys the steering is fine. Normal Non Return/Non feedback cable steering that behaves as it should The boat seems to track as you would expect with normal tourque but lists to port. The battery is stored starboard. The transducer is also mounted starboard. When I said the weight distribution was fine I meant weight of crew and moveable objects etc were all equally distributed. Next time out I will try and load a bit more starboard biased to compensate. The only thing not "stock standard" about my hull-motor set up is the addition of a troll-o-matic baffle but the listing was noticed before I put that on

The listing is not alarming or dangerous but definitely noticeable and something I'm not used to with my previous boats (Quinnies). It does concern me just a little when I have a fair wind hammering from the starboard quarter under way. The mechanic's explanation was that the particular shape of the Stacer evo advance hull, which flattens out from keel to chines at the rear quarter of the boat, whilst enhancing at rest stability, exentuates the steering torque under way and thus can cause a list?.

stang69
04-05-2014, 08:57 PM
Most deep V hulls experience prop torque. And most lean into the wind. Happens when the boat is on the plane with not alot of the hull in the water. Even though the Stacer isnt a deep V, it sounds like prop torque, especially with a Yamaha 70 4 stroke on the back. This same problem happens with alot of Suzuki powered deep V fibreglass boats because they swing big props. (oops, I'm not allowed to say anything bad about Suzukis around here haha)
The leaning into the wind phenomenon happens mainly in bay situations with short chop and windy conditions. Happens port and starboard sides.
As for North QLD chop, that shit is real. When you get the massive tides, in conjunction with a stiff South Easterly inside the reef, the chop is nasty. Much much worse than experienced in Port Phillip or Moreton bays because they dont have the big tides working against the wind.

Austin
04-05-2014, 09:06 PM
After a full refit/resto where i kept a complete track of any weight changes left/right/fwd/aft and had an F70A put on the back..the very first water test gave me...guess what...a slight lean to port when i was planing above about 35-40kph (4.8m glass rig) I was a bit disappointed thinking i had the weights somehow wrong, but later that day i assumed it was prop torque and wasnt overly concerned...mainly coz i had the 60l moveable livey tank i made up onboard and when i moved some ballast the lean went away....when i was solo..nothing..with one passenger i noticed the slight lean...when he moved to stand centre rather than in pass seat it corrected. So it was simply an easy fix for me with ballast...when alone 50ltrs of water is carried in centre down back.....when 1 other onboard 50ltrs water carried under or behind helm seat to compensate. I have never even bothered to actually seek out the real reason coz it simply isnt an issue. I thought i could correct by moving one of the batteries...i.e. take 30kg off port side and add the 30kg to stbd = 60kg shift...but havent even bothered doing that. To me just about all boats have little irks and quirks u simply compensate for and rapidly becomes a habit. I'm left thinking its probably just a bit of a torque/prop thing coz they do seem a largish prop. Luv the donk and performance and this simply wasnt an issue for me...BUT i'm damn curious now what others are thinking.

One more thing i would check on though...do you find the effect is more when u are up on the plane ? rather than any effect getting out of the hole ?

A lean to port is a very common issue with many well known brands and seems almost a random thing....especially around the 4.7-5.5m size. There is an effect (i forget the exact name of it) involving the wind (hope someone out there knows it and what its called)...and it inevitably causes a lean to port...VERY common and well known to the guys with trailer rigs on Port Phillip Bay for instance but doesnt often get mentioned in the usual "ramp talk" here in Sydney or up in Qld.

It involves the wind hitting on the Port side of the boat whilst up on the plane...has the effect of forcing the port side down somehow. When it was mentioned to me i suddenly noticed any slight lean WAS actually increased when heading slightly into wind whilst on the plane with it hitting the port side. Sounds a bit bizzarre but i;m hoping someone else in here knows what i;m talking about so i dont sound like a bit of a goose for even mentioning it.

I'd also guess its a bit of prop torque...my F70A does have a fairly sizeable prop so i assume thats all it is...but at least have a think...does it seem to happen mainly whilst up on the plane or getting out of the hole ? I'd investigate other issues and not restrict it to the prop. Check if particular wind directions seem to reduce it or make it noticeable. Just a thought.

I'd also add to the list the thought it might be a poor job mounting the engine. Just another possible worth checking out,.

Weird though...these modern tinnies around 4.7-5m are so incredibly beamy/stable, and dont have much side profile exposed to the wind that its hard to imagine what else it could be other than a bit of prop effect or at worst..an uneven/hook hull. They dont draw much and have little bite into the water, so i just thought i;d at east raise that wind effect to port as a "down the list" possibility that we know DOES happen to at least some rigs.

if it was me..i;d take her down at a non busy time and hammer it out of the hole with the steering dead centre and hands only resting lightly on the wheel...experiment with weight...experiment to see if trimming in and out changes anything...and take note of conditions such as breeze and chop direction to try to narrow it down to WHEN it seems most noticeable..otherwise can be a time consuming process. i.e. gather a few clues first.
Either way i wouldnt let it sour any thoughts on your new rig...pretty common thing and you'll get to the bottom of it.

Thanks Deckie. Much thought in that reply with plenty of possibilities. The lean does happen when up on the plane and not getting out of the hole. Don't get me wrong...I'm more than happy with the rig and it's performance it's just a little quirk that is quite noticable to all who have been in the boat and I was curious to find opinions on what could be causing it. I'll experiment with ballast "shifting" next time I'm out.