Dart 15 Forums

The rudder blades keep popping up especially to windward.
Have tried filing the slot a bit to let the rollers drop down further and tightened it all.
A little better.
It has only started since replacing the old aluminium pivots, washers etc.
Could it be the springs getting a bit soft.
Any help appreciated.
Chris

Sounds like you've done all the right things. If you haven't already, its worth removing, cleaning and lubricating all the moving parts in the rudder lock (strop, sheave, rollers, pin, stock grooves). While doing that, make sure there are no parts missing - for example (if I recall correctly) the grooves in the rudder stock along which the rollers move have stainless inserts - I did once notice one of mine starting to work loose from the stock.

I'm surprised that the rudders are mainly tripping upwind, so I wonder if that is a pointer - though I'm not sure at what. When I've had this problem in the past it was worse reaching and downwind when speeds are higher (more backward pressure on the blades) and lateral forces are lower (blades are more free to move).

I think the best bet is to put your boat up on the trolley bows down next to another 15. Raise and lower the blades on both boats, comparing the blade movement and locking action closely to see what is different about yours. For example, does the roller drop back into the blade by the same amount - if not maybe the strop is too short/stiff or (as you suggest) the spring is not providing enough force. Also check for excessive play of the blade within the stock when locked down (front/back and side/side). 15 rudders are not the most refined in this regard so some play is unavoidable, but excessive movement might be a factor. Sorry I can't suggest anything more definitive than that.

Update, thanks David, we have come up with a theory, or should I say Erling has. Over time the spring holding the rollers in position might have become soft. We are going to fit them with break fluid tubing, a bit thicker, hence hopefully putting a bit more pressure on the rollers.
Then hey presto it may work otherwise try new springs.
Perhaps you might know why quite a lot of rudder anvils get groves worn in them.
Obviously in the down position.
My theory is that the bushes etc are not tight enough, or badly worn allowing sideways movement on the foil against the stationary rollers.
Cheers Chris

Fingers crossed you find a solution.

Regarding the springs - someone once suggested to me a long time ago that it is better to store your rudders in the down position because the springs will then spend most of their life extended, not compressed, and so retain strength. I've done it with mine ever since though I don't know how much difference it makes. If your boat gear storage space is sufficient it would be a good habit to adopt if you don't already.

Sounds like a plan.
I bet if you went around our boat park 95% would be in the up position, that is the way they will be taken off and thrown under the cover. I know I do it.
Cheers Chris

Hadn't thought about that the rudders when hung up in the sail loft are not up or down so the spring is at maximum compression. They were actually worse on the reach and run but even came up upwind occasionally.