Genoa car moving backwards under load

[LongRange]

My Dufour 455GL has genoa cars with simple plungers that are supposed to lock into place and prevent movement. Trouble is, they don't, and both genoa cars tend to move backwards even under moderate load (say 15kn winds).

The gear is Lewmar, but presumably an older model as the boat is a 2005 vintage. The cars look very similar to this, except the plungers are anodised black:



The track and cars look fine, at least for their age. There is no obvious pitting of alloy or erosion around the holes in the track. There seems to be little play. I have carefully cleaned the holes in the track, lubricated the plunger, and once in place I cannot move the car by force.

However, under sailing loads the cars almost always tend to migrate backwards.

Is this just par for the course with these types of plunger systems? I like the simplicity of moving the car where I want it, and I would rather not introduce the complexity of an additional rope tackle to pull the car forward and keep it in place.

Is it likely that the cars or plungers or tracks are simply worn, and can the relevant bits be replaced?

Thanks in advance for all info and suggestions.

[dfelsent]

The car is not supposed to move when locked in place.
The plunger pin is supposed to go into one of the small holes in the track.
It is easy to get the plunger in one of the track fastening screw holes instead.
Double check that. Also check that the pin is going all the way into the hole.
Check that there are no foreign objects at the bottom of the hole. Make sure that nothing is catching the pin and pulling it up when tacking or curling the sail.
Lastly inspect the holes and plunger pin for excessive wear.

[travellerw]

We have those same Lewmar cars and we have the exact same problem you describe.

I have been pondering how to solve it but haven't come up with anything yet.

[Sailmonkey]

Is the plunger spring intact?

[LongRange]

(Both cars do this, to one extent or another.)

I am definitely using the locking holes, not the (shallower) screw holes in the track.

The springs are intact but seemingly not very strong. I am able to manually work the plunger a bit deeper than what the spring manages on its own. Even then, with the plunger all the way down as far as it'll go, the car still migrates backwards under load.

It seems telling that the plunger never seems to engage again. I have watched the cars slowly moving back, at say a centimetre per second, and the plungers never re-engage.

It is almost as if the back 'n' forth forces of sailing loads cause the plunger pin to slowly walk up the sides of the hole, and then... usually it's all the way back to the endstop. I cannot spot anything wrong with the track that would enable that "climbing" behaviour.

Interesting to hear of the same problem on another boat with the same gear. Perhaps it is a design defect.

[Suijin]

Are they installed facing the right direction? Stranger things have happened...

[LongRange]

Originally Posted by Suijin

Are they installed facing the right direction? Stranger things have happened...

Yes. Plunger-forward, toward the genoa, which lets the smaller secondary rollers deal with side loading.

In the photo I linked to, the genoa clew would be to the right of the car.

[meirriba]

We do have similar issue with Lewmar track, but only intermittently. Depends how aggresdively I push the plunger.
On racing boats there is usually a system that both keeps car in position and allows to move it under load. No plunger, lines attached to both sides of the car that go to the cocpit where they are secured with clamcleats.
If you google it you will probably find pictures.

[john2445]

Per Suijin's idea, turn them around. The sheave should face the sail, the plunger at the rear. At least mine have always been that way, but then I've never had a car with side rollers either. Can't hurt to try.

[amiller]

I've had the same problem, and it's not user error.

My solution was to use a piece of 2mm dyneema threaded through the hole at the front of the car, looped through a little gap between the front of the track and the end cap. That way I could tie the car in place.

Of course...the right thing to do is admit that the system is old and replace the track and cars with a newer system, one that allows you to adjust the cars from the helm.

[Seighlor]

Here's another guy that's had the same problem. This was some years ago and, as I recall, the blocks were made by Schaefer. Schaefer replaced the bases with screw-down type locks and the problem was resolved. Another possibility is to use "stoppers" behind your blocks. I had a pair of these that I used as a safety backup. Don't recall who made them and in checking current catalogs I do not see any listed.

[Stu Jackson]

Why keep fighting the same issue.


Either buy fixed pin stop cars or the adjustable cars.


Garhauer is a great source.

[robregje]

Just asked the producer

[Jannie Radiance]

The force of the genoa sheet on the car is upward. The genoa car lifts up and that lift is enough to unclip the pin. Tie a line behind the car onto a stanchion base. Feed the line through the car ( like your sheet would.) make a loop on the end and attach it to a halyard. Wind the halyard a little until you feel you have a bit of tension. For heavens sake, dont rip it out of the deck. Now tap the car with a rubber mallet. Gently... see .... there it moves...
You’re welcome!!!

[jmschmidt]

I've never seen one of these where the plunger/pin on a track mounted genoa block is forward toward the sail. The plunger/pin normally is aft so the it can be adjusted under load by one or two beefy guys stepping on the loaded sheet just forward of the car to momentarily hold the sheet parallel with the deck. Then the pin can be pulled and the car adjusted forward or aft to allow for differing points of sail. If the plunger/pin were forward it would be underneath the sheet when stepped on making it difficult to release and reset to make the adjustment.