You might have read my previous article and thus realize that I´ve finally made it to bring GEKKO back to the water: season 2 has started and I am excited! The first sailing weekend with my kids hasn´t been that intensive since I didn´t want to overstress the boys with too much sailing, but nevertheless, the season´s start was a real success. Besides checking the whole boat, er rigging and the sails (except for the Gennaker) I also tested the anchor setup and there was another item on my list to be crossed off: The rudders.
Thinking back to the big maiden voyage on GEKKO a year ago I remember that there was a tiny detail really annoying me, well, more than that, really making me worry about. That´s the vibrations in the rudder blades, especially within the starboard one. Starting at around 6-7 knots boat speed, the noise became louder and higher pitched. Up at 10 knots boat speed it became unbearable and so loud, up to a point where I really feared it would hit resonance frequency and explode …
Seascape yard and the guys told me to simply sand off the trailing edges of the blades, which we did. Well, it was done by Finn, our skilled master-rigger and boat builder, who took one hour or so to really elaborately sand down the edges – as sharp as a knife! – and sealed it again with Epoxy and antifouling protection. You might read the full article on the rudder blade treatment here. Now it was time to see if the work was worth it and if sharpening the edges did the trick.
Like a warm knife cutting butter …
First things first: It worked not just fine, it was a miracle! We´ve had winds with up to 15 knots TWS, not all too much but fairly okay for a shakedown cruise after winter season with kids aboard. The boat sped up to 8.5 knots SOG upwind and hit 10 knots downwind (with first reef in the main, for the kids). But we became fast enough t provoke rudder noise – starting at 6 knots boatspeed the rudders became loud in the past. But now? Nothing!
I heard absolutely nothing! No groaning, no moaning, no screeching – the blades just did what they are supposed to do, cutting through the water, correcting the course of the boat and holding on to the direction through the waves I chose them to go. It really works! Trying to provoke some vibrations by manually changing course a bit rougher, harder, the rudders worked absolutely noiseless. No sound anymore!
So I´d say, Finn, your work is spotless. Along with the sanding tips I received from Andraz Mihelin this little thing did do the trick. I was happy: The noise was really annoying and besides Seascape assured me that the rudders won´t ever break due to “resonance”, I remember going faster than 14 knots SOG and the sound was absolutely unbearable. I couldn´t stand it, it kind of coked up the fun of sailing GEKKO. Now I am just happy: Sailing silently, effortless – perfect!
Should everybody sharpen the trailing edges?
Now, is this the trick everyone should apply to their rudder blades? Well, certainly yes if the blades vibrate and make loud noises. You should consider to sand down and sharpen the edges of your rudder too, take out the boat of the water and have it done. But – consult a pro who is familiar with your type of boat and ask first. Also, be careful not to take off too much and thus alter the shape of your rudder. Its form has been deliberately constructed to have a certain form, any grinder works amazingly fast in taking away substance. Also, seal it tightly and elaborately since you don´t want to have a soaked rudder blade full of water.
I can only say that I am happy: Sailing GEKKO is so much more fun without that noise! I look forward to my next dash out, preferably alone, when I hopefully will have some more wind to check the higher speeds. There are some minor things to check, but this was the one big item that was grinding my gears over winter and I am really relieved to see it worked out so fine. Thanks Andraz, thanks Finn!
You might as well be interested to read these related articles:
Rudder blades tuning
Single rudder configurations: Still valid?
Appendages iterations on sailboats: Matteo Polli