boat leaning under power

[spilly]

my allycraft 4.75 leans to the right (down on the helm side) but only when on the plane. The more throttle I give it the worse it lists and I don't know why. What's more confusing to me is that it only does it when heading into the current or tide. Running with the tide it remains level and behaves normally. I've had the Hydrofoils off the motor, but this makes no difference. Has anyone had the same problem? How can I fix this problem ???

[Capt_Asparagus]

What is the wind doing? A lot of people do not realise that a boat will heel over INTO the wind when you are moving along fast. If you had a bit of breeze, and it doesn't have to be much, coming from that side, then that could have been the reason.

The reason is that wind on one side of the boat causes drag, while causes lift on the other side, just like a planes wing. Something like that anyhow.
cheers, Stu.

[Spaniard_King]

Check your engine height??

When the cav plate on the engine is trimmed horizontal is it level with above or below the Bottom of the boat.
To check this use a straight edge running off the bottom of the hull back towards
the engine see if the cav plate is as mentioned above.

Typically it should be level with or 1/2inch above the bottom of the hull

cheers

Garry

[Angla]

Spilly, Look at the small fin behind the prop. On my 135 Optimax it is slightly pointing to port at the front, as this corrects what you are describing I believe.
You could loosen it and make a small adjustment then test it by trial and error. I would mark it's original position for later reference if required

Angla

[blaze]

I have only heard of the little fin (trim tab/sacrafisial annode being a problem with steering being heavy one way and not holding in the neutral position. I would first of all try balancing the boat, as in even dristrabution of weight, normally the cause in a small boat, in vessel 5.5m and above or a vessel with a lot of height above the water line you will get a problem called wind listing, unussaul I believe in smaller vessels
cheers
blaze

[spilly]

I thougt it was something to do with the wind at first, but yesterday the wind was on the opposite side and yet the boat remained level. It seems to only lean the one way. The boat is loaded evenly and it's level at rest so I don't think this is a fault, even with a much heavier person than me in the passenger side it still lists to the helm side when operating at speed into the current only ???

[Spaniard_King]

Believe it or not, your cav plate is the key ::)

Garry

[spilly]

Garry, Can you explain a bit more
Cheers Steve

[Spaniard_King]

See my post above about the engine height, your boat actually falls to one side and finds it hard to recover. You will find that if you trim up the engine a little it will reduce this problem but to fix it you will probably be changing the engine height on the transon. This is easily done at home by yourself.

Garry

[DaveSue_Fishos_Two]

I agree wholeheartly with Garry. It sounds to me that your boat is not actually 'leaning' to one side but 'falling' to one side. Your answer does lie in the trimming of your motor in relation to the height of the cavitation plate to the hull.

Dave

[Capt_Asparagus]

Either that, or......... it's POSESSED!!!!! [smiley=wreck.gif]
And, beause it is leaning to the right, possibly possessed by an ex- nazi or something.....

Oooo-OooeEeerr!

Perhaps a nice excorcism would be advisable?

Or that cav plate thing, but how mundane!
Good luck (with the haunted boat and all), cheers, Stu.

[Angla]

I reckon the wife has done something that makes the boat turn so you will come back home..............
I'd do the cav plate check too so you could keep travelling away from home.

Angla

[RobSee]

Capt Asparagus............ we need and old priest and a young priest...........

[chemmy]

how long has it been doing this whowl leaning thing???

[Dunaruna]

Spilly, do you have a doel fin/ hydrofoil/ whale tail type devise fitted?

Aldo

[gunna]

My 4.55 Ally will pull to the left when I trim out too much. Have you found it changes at all with different trim ??

[Mr_Bean]

Before adjusting anything, I would first go back to the basics.

1. Are you sure cross wind is not an issue?

2. Has the motor been installed exactly in the centre of the boat? Get out a tape, a piece of string and a pencil and check.

3. Is the hull lifting on the same side as the down stroke of the propellor? If it is you may be feeling the effect of Propellor Torque, that is, propellor going in one direction and the motor trying to turn the boat in the other direction.

4. Does the underside of the boat have any irregularities? Look for dings or buckles that may be upsetting the boat balance.

Please, let us know what you find (if anything).

- Darren

[spilly]

Thanks for the advise everyone. I still haven"t sorted the problem yet but I think some things can be ruled out. Firstly I've only had the boat for 3 months and I only noticed the problem after i bought it, not in the water test (maybe it is possessed). It's got two piece hydrofoils fitted but I took them off and it didn't make any difference.

The listing seems to be slightly less if the motor is trimmed out slightly but I assume this is because there is less hull in the water. I checked the height of the cav plate in relation to the hull, it's about level with the centre point. Motor can't go any lower anyway!! There are a couple of small dings in the underside of the hull on the side it leans to about 3 feet from the stern but I've had bigger dints in previous boats with no apparent problems.

Not sure if the motor is mounted perpendicular to the centreline down the stern. Could a slight angle cause hassles? If so how do I check it (would only be oput a flyshi...)

[frankj]

If the motor is not perpendicular, the boat will list over.
I know this because mine suffers from the same thing. One day I'm gonna fix it.

[qcr]

I have exactly the same problem with my 455 coastrunner and havent found the cause . I will now look at some of the suggestions put forward here.

[Barrymundi]

I changed the transducer MOUNTING bracket on my 6 metre boat.

The boat leaned over. Raised the transducer, problem fixed. I was surprised how a little mounting bracket dragging through the water could cause my boat to lean over.

Al

[DaveSue_Fishos_Two]

If your motor is sitting down hard on the transom, which it probably is if it can't go any lower, then it would be reasonable to assume that it is perpendicular. However, is centred? You could try measuring the EXACT width of the transom across the top, make a mark on the transom, and then measure etc your motor brackets to centre it. If all else fails, I would ring the manufacturer and ask them. :-/

Hope you sort it out mate

Dave

[gofishin]

Spilly,

One obvious question that hasn’t been asked (as far as I can see) – is it a new boat & still under warranty? If it is then take it back to your dealer & let us know what the outcome is. Otherwise you can check as follows (& I assume the helm is on the stb side)…

FYI ‘Leaning’ in pressed tinnies is not that uncommon, & mostly is a result of non symmetrical planning surfaces generating different lift/drag ratios either side of the keel. There are/can be numerous contributing factors/causes, from construction faults thru to trailer problems, but at this stage it is best to concentrate on the common ones.

As others have mentioned, check that the motor is central on the transom, and plum to the keel and stem/centre line of the boat, but also check the transom is not offset on the boat (believe it or not I have seen a transom on a tinnie 30mm off centre!).

From the stern, crouch down & look along the bottom sheets & compare the curvature between port & stb. Generally tinnies are made with a ‘rocker’ (bow/belly or downward bulge) in both the bottom sheets & a slight rocker in the keel. Look for a rocker in the stb side bottom sheet and a lack of, or even a ‘hog’ in the port side sheet. A hog would be like an upward hollow or dent. Also check that the boat has not been made with a twist in – not so hard to do if the correct construction methods are not adhered to.

Prop torque in this case can be discounted as the boat is leaning the wrong way, & in fact prop torque will actually be helping to correct the lean!

Your boat will have an external keel. Look along it & check that it does not have a slight hook or bend in it to the port. If it does, the motor will need to be slightly turned to stb to keep the boat going ahead in a straight line, thus giving you a slight list to stb.

Check your trailer is adjusted properly, with most of the weight on the keel & not on the bottom sheets. Hopefully it has side skids & not rollers, as these are a no-no with pressed tinnies. If it does have rollers, check that the port aft roller has not dented the bottom sheet just forward of the transom, creating a ‘trim tab’.

On smaller tinnies, ‘on-the-piss’ biminies & canopies can cause leaning, but should not be a problem in a 4.75m.

Hope this helps.

[peterreb]

Could it be prop pull,ie rotation of the prop
Cheers Peter

[blaze]

People talk about poor bottom sides of tinnies creating problems, I have an OLD ROUGH AS GUTS tinnie that was orginally a tender on a cray boat, dented rather baddly and still gives a good ride for what it is. I just through a main motor and an auxilly on when I want to use it and away I go, no measuring hieght or if the motors even. Its an old brooker 14', so I wonder why these problems dont occur with that one.
cheers
blaze

[spilly]

Can't find any hollows in the hull, but after measuring for centre of motor I've found it's mounted slightly off centre. Maybe this is it!!!

[Swerve]

Before adjusting anything, I would first go back to the basics.<br><br>1. #Are you sure cross wind is not an issue?<br><br>2. #Has the motor been installed exactly in the centre of the boat? Get out a tape, a piece of string and a pencil and check.<br><br>3. #Is the hull lifting on the same side as the down stroke of the propellor? If it is you #may be feeling the effect of Propellor Torque, that is, propellor going in one direction and the motor trying to turn the boat in the other direction.<br><br>4. #Does the underside of the boat have any irregularities? Look for dings or buckles that may be upsetting the boat balance.<br><br>Please, let us know what you find (if anything).<br><br>- Darren

This is a really usefull thread. My new Quintrex 480 Freedomsport (70hp 2 stroke yammie) is suffering from a lean to Port (more so under load). I have confirmed it is not the wind or a weight distribution. It takes a whole person (80kg) on the starboard side to counter balance the lean.

On the weekend I noticed it was more evident with the extra load, so I'm starting to think it is Propellor Torque. If it is prop tourqe can I reduce the lean with the tab thingo behind he prop ? I'm going to check all the other things noted above also. It is really starting to annoy me as its a big lean with 4 adults and dog in boat. When only 2 people its only slight lean. Also when towing with two people in boat and ski rope on the right tow hook it still leans at a large angle.

Steve

[Swerve]

OK, Looked at my cavitation plate height and I think its to low. I have trimmed it to about 3 wear I normaly use it. What do you all think

Steve

[Swerve]

and

[Swerve]

and again

[Just_One_More_Cast]

Hi Swerve

I acn sympathise with you as I have recently spent quite some time fixing the same problem on my older model 3.8m Stacer with 30HP Johnson.

Like you, I was driven to search long dead threads about the problem and tried several things to fix it, mine was leaning so baddly to port when on the plane that it was downright scary and dangerous in any sort of chop.

Also like you, I found there are about 100 possible reasons for it, however, I narrowed them down to the ones that kept coming up and last weekend I lifted the motor and made sure it was dead centre. Guess what, we went fishing for half a day and only picked up one decent 2lb Yellowbelly, but it was one of the best trips of my life because the damn bot finally sat level on the plane. Only those who have had a similar problem for some time can understand the elation.

I will not offer comment on whether your cav plate is at the right height or not, because after lengthy late night research I found that the recommendation varied from about 1.5 inches above keel to about 1 inch below. Presumably it varies depending on the style of hull, the power of the motor and god knows what else.

I finally decided that it is not that hard to lift it an inch, stick a block of wood under it, and take it out for a blast. I would imagine you will have to notice some change, be it for better or worse. at least then you have a starting point.
For me it was an instant fix. Give it a go and see.

[Angla]

It does look a little low

Heres mine

Angla

[Swerve]

Thanks Just_One_More_Cast and Angla,

I do have one more bolt hole the engine can be rasied up a inch or so. This would be reasonable simple and only involve unbolting and bolting.

To make sure te engine is perpendicular how do you do this with the engine on ? If I take the engine off and mark directly in the centre of the current engine position, and map out on the transom the correct centre, perpendiclaur position. With the engine in the way its quite difficult ? Does someone know if the four bolt holes on a yammie 70 2 stroke are evenly spaced from teh centre etc !!!

Also with the I-Bean keel thingo, does this count as the bottom of the hull or the flat alloy 1" above ???

Steve

[dinky]

Spilly,I also have a 4.75 allycraft cuddy.mine does the same thing going into current but,had a 15-20 knotts SE so the weather man said.I will check this cav plate thing too! Will get back to u all :)

[catchy_fishy]

[quote author=Mr_Bean link=1117331888/15#16 date=1117506535]
This is a really usefull thread. My new Quintrex 480 Freedomsport (70hp 2 stroke yammie) is suffering from a lean to Port


Is this how you came to choose your Ausfish name ? [smiley=angel.gif]

[predator]

What do you all think


Motor seems too low to me. I would be lifting it up by 1 hole for a start, and see if there is any improvement..

[ahoj]

Crazy idea-- is you hull even? one side more proud then the other--- I didn't say that......... I didn't -- ;D ;D ;D ;DI didn't ;D ;D ;D ;D

Ahoj

[Swerve]

[quote author=Mr_Bean link=1117331888/15#16 date=1117506535]
This is a really usefull thread. My new Quintrex 480 Freedomsport (70hp 2 stroke yammie) is suffering from a lean to Port


Is this how you came to choose your Ausfish name ? [smiley=angel.gif]


Have had it for a long time as a nickname. Used to ice speed skate and I would SWERVE all over the place. Hence I got the name Swerve. On all forums I use this so you will see me around

www.careel.com
www.outerlimits4x4.com

My last boat was a Careel 18 Traileryacht. Got tired of raising a mast all the time and my Mrs wouldnt help that much. Life much more comftable in the motorboat now. Mrs is coming out all the time now.

Plus I can fish more !

Steve

[Swerve]

What do you all think


Motor seems too low to me. I would be lifting it up by 1 hole for a start, and see if there is any improvement..

I have one hole left to move it up. The boat is getting serviced in 18 hours so might wait till then. How hard is it to do yourself ? recommended ? trick to it ?


[quote]Crazy idea-- is you hull even? #one side more proud then the other--- I didn't say that......... I didn't -- # #I didn't # #

Ahoj

I was looking at the hull for hours last night. Trying to work out how to measure it. Still cant work out a simple method to measure if the engine is straight or crooked, centered or not, or hull even both sides ???? Somedays I just hate boats !

Steve

[Just_One_More_Cast]

Hi Swerve, I believe most motors on your sized boat can be easily lifted by puting a block under bottom of leg, winding up jocky wheel until it motor is firmon block, then undo pinsbolts or whatever holds it in position. It is then simply a matter of winding jockey wheel up until motor is over the hole you want, replace pin and windi jockey wheel down.

You should do this with at least one or preferably two assistants. One in charge of jockey, one to juggle motor and one to remove/replace pins or bolts.

[Swerve]

Hi Swerve, I believe most motors on your sized boat can be easily lifted by puting a block under bottom of leg, winding up jocky wheel until it motor is firmon block, then undo pinsbolts or whatever holds it in position. It is then simply a matter of winding jockey wheel up until motor is over the hole you want, replace pin and windi jockey wheel down.

You should do this with at least one or preferably two assistants. One in charge of jockey, one to juggle motor and one to remove/replace pins or bolts.

Excellant !!

It sounds so simple, why didnt I think of it (Brain still has cogs and gears ticking over) Will arrange some mates this weekend and bingo.

Cant wait to try it, but it does piss me off when you buy a boat new from a dealer and the bugger dont know shite about setting them up. They always try and shrug it off as normal.

Thanks

Steve

[bassbasher]

You will find that the listing is more pronounced when the motor is trimmed in. The cause is the combined effect of engine torque and engine trim angle. As you trim the motor out, the listing will disappear. All boats do it. If you can't trim out because you want a bow-down ride for the sea conditions, you will just have to redistribute weight, i.e stand to the left of the console. Trim tabs are designed to correct this problem. If you change the adjustable fin on the leg, you will cause steering imbalance and the motor will turn hard one way or the other.

[dinky]

my cav plate is about 1/2 inch above also. :-/