Rudder Modifications

Hi Phil,

I was especially interested in this part of your "Introduce Yourself" post, especially after viewing the videos you mention, and seeing the "Look No Hands" caption part way through the second one:

dusksailor wrote

I have made a straighter and deeper rudder to overcome stalling and rounding up. It's also much better balanced. See the vids below.
Before with old rudder
After with new rudder

The new blade was one I made and fitted to a Prelude for a few weeks, which explains the lighter patch at the top.

Do, please, explain the thinking/science behind it.

Up till now the only changes to the standard rudder that I recall being reported have been to allow the rudder blade to lift with the purpose of prevent grounding of the rudder on launch or recovery from the trailer.

Although some of these rudders, most notably:
https://www.seahawk17.org.uk/boat-gallery-uk-lastresort.php
show similarities to your enlarged blade, no one has described this as being an important feature of the change, so I think I tended to assume that it was just a case of making use of what happened to be hanging around in their shed.

I also now realise that there is nothing in the Boat Shed section of the site on rudder modifications, so what you tell me could be the foundation of the page.

Do explain about the angles labelled "1" and "2" in your photographs (shown below). I can see that "2" follows the line of the pintles and hence the transom. Does, "1" represent the vertical? or some other angle?

Quite right Greg. Line 1 is the vertical and Line 2 the pintle pivot line. There is no science involved. I tried it on the Line 1 first and it worked a treat so I haven’t even bothered trying it on Line 2. I would imagine it would be more balanced (but I have next to no weather-helm anyway) but I think it would give a poor entry to the leading edge when the tiller is put over as the boat is heeled.
I don’t find there is much chance on Windermere of grounding so the few extra inches are not a worry. Similarly a pivoting blade would save the rudder in the event of striking a rogue rock, but the way I have done it is more stable and if I did hit a rock the pintle brackets would break before the rudder or transom damaged. I consider that a reasonable risk. I’ve only graunched over a rock once in 8 years here.

On another matter, I replaced my baggy original mainsail with a used one from an Osprey dinghy, which is a perfect fit. I think the luff was about 3” longer.

Phil