Welcome to TH-cam, so excited to see how the boat projects come along. Also a bit of feedback. Your music is much louder than the speaking in the videos, so something to adjust and look out for when editing.
Yes, the winglets will be similar to what the Dazcat guys are doing but much smaller. The primary purpose for the winglets on the set up Im intending is drag reduction. The second function is reducing pitching a little. As the rudders I built as a temporary fix are quite big I dont need the winglets, so its a project that has gone to the bottom of the list. IT is one that Im super keen to pick up on as it will have some cool benefits.
I am currently building an 11.6m cat and am almost finished buiilding the rudders very much along the same lines as you did with SS stock and tangs and foam blade. My question is should I be concerned about the 10-20mm of SS that will be permanently exposed to salt water and is there anything I should do to protect it? Also if the rudder is not electrically connected to anything else on the boat does it need any galvanic protection etc.
If the SS stock is completely isolated it does not need galvanic protection. I am not following the first part of your question: there should not be a 10-20mm gap between the rudder and your hull. It should be taken up with a thrust washer and ideally you want the rudder to be within a few mm of the hull. This makes makes a MASSIVE!!! difference to the efficiency of the rudder.
@@youngbarnacles Yes the gap between rudder and hull will only be about 10mm but the shaft will still be exposed for about 20mm. I have built everything from scratch using a graphite lined fibreglass tube and the "washers" consist a stainless ring partially inside the hull and a hand cut UHMW-PE washer between that and the rudder blade. There are no production components involved. The "washers" do not seal the shaft from the water however, but you have answered my main question, thank you. I have another question. I am considering adding winglets. How aerodynamic do these have to be? Would a simple flat wing stuck on the flat bottom of the rudder be OK or do they have to have an aerofoil section?
Why wouldn't you drop the rudder posts and do this horizontally on a table? It seems like it would be easier. I'm sure there are reasons you did it this way but I'd like to know why. I built an F-9A in the early 90's (carbon over Duracore) and I'm thinking about a transom extension and new daggerboard/cassette style rudder.
Hi Steve, we would have loved to have removed the rudder stocks from the boat. The reason that we did not is due to the tiller fitting in the boat not being able to be removed at the moment. Also due to the boat being low to the ground and not being able to get it in and out. Well done with building the F-9A they are a cool little boat. Having a rudder cassette and blade makes life much easier when dealing with shallow water and launching.
The Stainless stock failed from fatigue. It was a risk I knew we would take putting the blade on to an existing stock, but that was what we could afford and manage at the time. It was a temporary solution in the long run, but I was hoping to make it all the way across the Atlantic ;)
Try using box section for the rudder that tapers to tumbler that fits into boat
awesome work, be interesting to see how the winglets go on the bottom of the rudders, supposed to damp hobby horsing quite substantially
Thanks! Yes we hope to reduce hobby horsing with the winglets. Having the rudders bolt on means that we can play with settings a bit too.
Welcome to TH-cam, so excited to see how the boat projects come along. Also a bit of feedback. Your music is much louder than the speaking in the videos, so something to adjust and look out for when editing.
Good feedback thanks 👍
I also echo the desire for a follow-up on the winglets!! Will this be similar to the Dazcat design??
Yes, the winglets will be similar to what the Dazcat guys are doing but much smaller. The primary purpose for the winglets on the set up Im intending is drag reduction. The second function is reducing pitching a little.
As the rudders I built as a temporary fix are quite big I dont need the winglets, so its a project that has gone to the bottom of the list. IT is one that Im super keen to pick up on as it will have some cool benefits.
I am currently building an 11.6m cat and am almost finished buiilding the rudders very much along the same lines as you did with SS stock and tangs and foam blade. My question is should I be concerned about the 10-20mm of SS that will be permanently exposed to salt water and is there anything I should do to protect it? Also if the rudder is not electrically connected to anything else on the boat does it need any galvanic protection etc.
If the SS stock is completely isolated it does not need galvanic protection. I am not following the first part of your question: there should not be a 10-20mm gap between the rudder and your hull. It should be taken up with a thrust washer and ideally you want the rudder to be within a few mm of the hull. This makes makes a MASSIVE!!! difference to the efficiency of the rudder.
@@youngbarnacles Yes the gap between rudder and hull will only be about 10mm but the shaft will still be exposed for about 20mm. I have built everything from scratch using a graphite lined fibreglass tube and the "washers" consist a stainless ring partially inside the hull and a hand cut UHMW-PE washer between that and the rudder blade. There are no production components involved. The "washers" do not seal the shaft from the water however, but you have answered my main question, thank you.
I have another question. I am considering adding winglets. How aerodynamic do these have to be? Would a simple flat wing stuck on the flat bottom of the rudder be OK or do they have to have an aerofoil section?
Why wouldn't you drop the rudder posts and do this horizontally on a table? It seems like it would be easier. I'm sure there are reasons you did it this way but I'd like to know why.
I built an F-9A in the early 90's (carbon over Duracore) and I'm thinking about a transom extension and new daggerboard/cassette style rudder.
Hi Steve, we would have loved to have removed the rudder stocks from the boat. The reason that we did not is due to the tiller fitting in the boat not being able to be removed at the moment. Also due to the boat being low to the ground and not being able to get it in and out.
Well done with building the F-9A they are a cool little boat. Having a rudder cassette and blade makes life much easier when dealing with shallow water and launching.
How on earth did a rudder like that get lost? Did you guys hit something..?
The Stainless stock failed from fatigue. It was a risk I knew we would take putting the blade on to an existing stock, but that was what we could afford and manage at the time. It was a temporary solution in the long run, but I was hoping to make it all the way across the Atlantic ;)