sailboat pulls to starboard under power.

[Eibeltje]

We just installed a new engine/transmission on our Pearson 323.It has a offset shaft to starboard.Before the boat steered straid,you could take you hands off the wheel and it won't very the course except for wind and current changes.It had a counterclockwise (LH) prop.
When they build-ed in a new engine and transmission they also changed our prop from left handed to a clockwise turning prop (RH)Has this change something to do with the pulling from the boat under power to starboard ?

 

[Tom J]

The offset shaft is a great thing to have when it comes time to pull the shaft. No need to remove the rudder. It can also reduce "prop walk". I would think, though, if you reverse the direction of the shaft rotation, you would actually be increasing the prop walk.

 

[centerline]

absolutely.... it has everything to do with it.
that boat with the off set shaft may have been set up that way to use a left hand prop, and when a right hand prop is installed, it could make the problem double bad because of the off set.....

because of the water pressure being greater at the deeper depth of the lower radius of the turning blades on the prop, than it is on the upper radius of the blades, the prop will "walk" or crawl towards the direction that the prop turns due to the lower blades pushing against the greater pressure as they rotate around...

if your boat was set up with an offset shaft to counter this effect while using a left hand prop as the boat moves thru the water.... the right hand prop on that particular off set will double the effect of the prop walk....

 

[Eibeltje]

Reply:sailboat Pulls To Starboard Under Power

absolutely.... it has everything to do with it.
that boat with the off set shaft may have been set up that way to use a left hand prop, and when a right hand prop is installed, it could make the problem double bad because of the off set.....

because of the water pressure being greater at the deeper depth of the lower radius of the turning blades on the prop, than it is on the upper radius of the blades, the prop will "walk" or crawl towards the direction that the prop turns due to the lower blades pushing against the greater pressure as they rotate around...

if your boat was set up with an offset shaft to counter this effect while using a left hand prop as the boat moves thru the water.... the right hand prop on that particular off set will double the effect of the prop walk.

Thank you so much for taking the time to answer.

Is there any body out there who has a Pearson 323 with a offset shaft to starboard and can advice us which engine /transmission we could build in with a left handed propeller.(Left handed under warranty !!)

 

[Eibeltje]

Tank you so much for taking the time to answer.

Is there any body out there who has a Pearson 323 with a offset shaft to starboard and can advice us which engine/transmission we could build in with a left handed propeller Left handed under warranty !!)Beta marine has 25 HP.with ZF 15 MIV transmission but they talk a big deal about using the gearbox in reverse forward and advice you also about to put in that way a Oil cooler on the transmission,but if it comes to warranty they pull back)

 

[kloudie1]

Seems a little strange.. A clockwise prop walks to starboard but the boat pivots at the keel so that would make it turn to port? shaft offset to starboard.. if parallel offset (shaft true to center line but offset to stbd) then that would also make the boat want to turn to port.. if the shaft is angled to stbd from center, then that might push the stern to port and cause the boat to turn to starboard.but that should have happened also with the CCW rotating prop.? Seems like the new pull might be the interaction of the offset clockwise propwash acting in a different way on the rudder balancing area (in front of the post).. I dunno

 

[Eibeltje]

sailboat pulls to starboard under power

I dunno,but i understand that for clockwise turning props (RH) the rudder should be to starboard of the prop center line and for for counterclockwise turning props (LH) the position of the rudder should be to port of the prop center line to counteract the bow and turn it back toward the center line.
We have a shaft that is offset to starboard,so it is to starboard of the rudder so the center line of the prop is to starboard of the rudder that means that we need a left handed prop (counterclockwise ) under our butt.Do i understand this right ???? ORRRR

 

[centerline]

it is probably as simple as re-installing the left hand prop and changing the cable to pull the other direction when you put it in gear.....

 

[kloudie1]

Well, sorta, but what determines the "hand" of the prop is the direction the transmission turns when in forward gear. A left hand prop on a right hand turning engine will pull the boat backwards when in forward gear. To go to a left hand prop would require a new/different engine/transmission.

 

[Ron20324]

Bear in mind that any shaft postion other than true fore and aft, the prop is at an angle and it starts to work like a bow thruster- moves you sideways!

 

[Eibeltje]

And there the problem starts.
I want to re-power my Pearson with a 20/30 hp. engine with a V-Drive transmission with LH prop rotation to compensate for the starboard offset shaft.
Is there any LH rotating transmission for a V_Drive on the market ? (With Warranty !!)

 

[AWalker]

I may be just ignorant on this, however, does it really matter which way the transmission turns?

 

[Eibeltje]

What is ignorant ? Just ask if your mind start to go round and round and round.

Yes,if you have a offset shaft to starboard and you want to buy a V-Drive transmission
for a counterclockwise turning prop (LH)you are on your own (for Pearson 323) All the transmissions out there are for clockwise rotating props (RH).They will tell you that you can use the reverse mode for forward (what is not a big deal) and they even advice you to putt a oil cooler on your transmission if you want to use the reverse position for forward,but if you ask them about the warranty (if you get a new engine and transmission)they will not sign that paper because they know they have a lot of problems with that reverse little wheel what seems not to be to strong.It will be OK for forward use but not for a constant reverse use in forward.This little secret they don,t tell you
when you buy a engine and if you don't know you are a kind off screwed if your boat is not reacting well on this wrong change.

 

[centerline]

I may be just ignorant on this, however, does it really matter which way the transmission turns?

this is exactly my point when I said it may be as simple as reinstalling the LH prop and then changing the direction of engagement of the shift lever.... a lot of transmissions are just a gearbox that doesnt care which way it turns, because its made to turn both ways!.....

 

[Eibeltje]

Centerline thank you,
The problem is that we invested in a Beta 25 hp with a ZF 15 MIV transmission ,advised by the marinas top engine installer by a our loan of $ ........ you know.
We had a Volvo MD 11 with a left rotating prop . The boat was steering strait like a lineal except for wind and current.After the installation with a ZF 15 MIV transmission with a clockwise rotating propeller(RH) we found the boat pulling to starboard .They said we could go back to a counter clockwise rotation with shifting the reverse to forward.They even advice / warn you to put a oil cooler on the transmission because things get more heated.Well it get all more heated if you ask them ,what about the warranty ?They don't warranty this reversed used gearbox from reverse on a forward position !!!!!!What is your feeling.Than a totally other Beta info told us that they don't advice to use reverse in forward .And the top of the guru's told us "Running a velvet drive permanently in reverse is not good,whatever the ratio." Thank you .

 

[centerline]

Centerline thank you,
The problem is that we invested in a Beta 25 hp with a ZF 15 MIV transmission ,advised by the marinas top engine installer by a our loan of $ ........ you know.
We had a Volvo MD 11 with a left rotating prop . The boat was steering strait like a lineal except for wind and current.After the installation with a ZF 15 MIV transmission with a clockwise rotating propeller(RH) we found the boat pulling to starboard .They said we could go back to a counter clockwise rotation with shifting the reverse to forward.They even advice / warn you to put a oil cooler on the transmission because things get more heated.Well it get all more heated if you ask them ,what about the warranty ?They don't warranty this reversed used gearbox from reverse on a forward position !!!!!!What is your feeling.Than a totally other Beta info told us that they don't advice to use reverse in forward .And the top of the guru's told us "Running a velvet drive permanently in reverse is not good,whatever the ratio." Thank you .

with this bit of information i would make them get it right....

BUT... i dont know the details of the deal you made so i cant advise, but my thoughts are whoever helped you choose the repower option and did the install should have also done the engineering to make sure it would work before they went forward with the project.
so with that in mind, they should stand behind the issues that have been created due to their lack of attention to detail. legal action may need to be sought to get them to understand this more clearly.

but if you showed up at their doorstep with an engine and transmission and told them to install it in your boat, and they did.... well, you must understand that they did exactly as you told them to do and no fault will be on them if it was the wrong components for the boat, that you brought to them.


also, I would think in this modern marine world, with LH and RH props, and even some engines that turn in the opposite direction, that there would be an option to somehow change the normal operating rotation of the output shaft of almost any transmission...

but maybe this simple option has became a thing of the past and is obsolete now.......

 

[kloudie1]

I would learn to live with the pull before I ran the transmission in reverse as normal. Most marine transmissions have a lower gear ratio in reverse than they do in forward. (For instance, my Kanzaki has a 2.61:1 in forward and a 3.16:1 in reverse, about a 20% difference) That would mean a different prop pitch so that you'd not be "underpropped" when going forward. Engaging reverse gear in these transmissions involves engaging an idler shaft which reverses the output direction. Most idler shafts do not have as robust thrust bearings as the forward, direct drive load path has. I wouldn't run it in reverse all the time..
EDIT: The engine direction can be reversed by changing the camshaft and the starter. The transmission can (probably) be changed by interchanging fwd/rev cone clutches so that they lock instead of unlock in the new direction of rotation. The damper plate would have to be reversed too.. This drive train reversal would be a very expensive proposition.

 

[Eibeltje]

sailboat pulls to starboard under power

Thank you again,

I start to believe that I have the only Pearson boat with a V-Drive and offset shaft to starboard and a new engine /transmission with a right handed propeller what is pulling to starboard !How the hell do all the Pearson 323 owners install new engines and don't have any problems ? Do I post on the wrong forum because I like to hear more voices about this.
If a Pearson 323 needs to be re powered now a days (2013) what are the options what engines/transmissions ,clockwise /counterclockwise rotating propellers have been installed with satisfied /not so satisfied outcome ?This is a very important topic for every old Pearson 323 out there because I don't like the salesman dictating me a wrong engine/transmission for my boat I like my own Pearson 323 "sails " man advice and opinion !

 

[kloudie1]

"usually" (again speaking generalities) when the engine and transmission is replaced as a unit, the folks ordering the power unit will try to duplicate whatever is there.. The power units "usually" can be ordered from the factory in either direction of rotation.. Sometimes a good rebuild of the existing engine/transmission is easier (and a little cheaper) than replacing the whole unit..

 

[demaris]

i don't know your purchase agreement but borg-warner velvet drives (v drives too i think) can be purchased in both right and left hand versions. may be an option?