Swordfish elliptical rudder...

8 years 1 week ago #13699 by coldwater
Am keen on fitting an elliptical rudder to my Swordfish.
To other guys who have done this, are there any issues with the Fenn rudder shafts not being completely in line with the rudder axis?
ie. where the shaft enters the rudder.

Just wondering if I order an elliptical rudder, if it too would have to be an exact match of the Fenn rudder, whether it's skew or straight comparing the shaft to the rudder axis.
Does it even matter??!!

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13700 by robin.mousley
I'm not sure I understand the question 100% but I fitted an elliptical rudder to my SF.

The rudder as delivered didn't fit perfectly; the section in front of the pin would impact with hull as I swung it from side to side. So I had to file the material down a bit. Took a couple of minutes and then it worked perfectly.

I have two elliptical rudders - one is similar to but a little smaller than the Epic V10 rudder. This one I find a little too powerful for the SF - when traveling at speed down the face of a wave, if you kick the rudder too hard, the boat almost leaps out of the water!

The second is from Fenn themselves. It's a lot smaller and narrower in profile. In my opinion the profile is too narrow and leads to the rudder stalling.

So I'm looking for a compromise - something of the same shape as the bigger rudder (which I got from Orka paddles here in Cape Town) but cut down a little so that it's slightly bigger than the Fenn rudder (and has a meatier profile).

Rob

Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...
The following user(s) said Thank You: coldwater

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13707 by STEWART
I have done this, twice. Both times i ordered and received the elliptical rudder from Carbonolgy Sport. Simply took the fenn surf rudder off of the SF, replaced with the new elliptical rudder and was on the water.
When i spoke to Carbonology i asked for an eliptical rudder for a SF, not sure of any size differences.. but the fit was solid on both occassions and never had a problem after fitting.
The elliptical rudder, for me, made a world of difference. Not only downwind but also training paddles, the ski felt more 'secure' on the water.
Paddle Hard
The following user(s) said Thank You: coldwater

Please Log in or Create an account to join the conversation.

8 years 1 week ago - 8 years 1 week ago #13709 by Dicko
The other thing you can try, is removing the shaft from the rudder and resetting it further back. It sounds difficult but isn't that hard to do. Moving the shaft back a cm makes the rudder behave like an elptical rudder.

Before you start draw an outline on a piece of paper so you get the length and angle right when you reinsert the shaft. Mark around the shaft with a marking pen so you get the length right.

Drill out as much epoxy as you can from around the shaft...sometimes this is easy, sometimes hard, depends on the type of shaft. When you think you have cleared enough, stick the shaft in a vice and start twisting the rudder until it loosens.

Clear out a hole with a drill where the shaft is to be reinserted.

Replace the shaft and use a little 5 minute epoxy to get the angles and depth right. When its set put it in the vice and pour 24 hour epoxy in. In the morning fill the gap with a bit more 5 minute epoxy to make it flush.

Moving the rudder post back will make the rudder way more responsive and less likely to broach. Conversely if your rudder is too responsive you could move the post forward.

I have moved the post on my standard rudder back almost 2cm. It now behaves like my eliptical surf rudder, but without the drag from a larger surf rudder. Really good in medium sized downwinders.
The following user(s) said Thank You: coldwater

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13764 by GlenRusky
Coldwater, in my experience, ensure that you get all the dimensions correct before you purchase, particularly if buying from overseas. It will save the hassles of shipping back and forth.
I fitted an elliptical rudder to my Swordfish earlier this year. I am based in Australia and ordered it from South Africa. It is an Orka one which is very nicely made! Even though I specifically mentioned it was for a Swordfish, when it arrived, it didn't fit. The problem was that the diameter of the shaft was too wide by a couple of mm so it would not fit my boat. I then took my original rudder, photocopied it to exact size and also wrote down the dimensions and returned it all. This helped because the next one that came fitted perfectly. The angle where the rudder meets the boat is a little different but I don't notice anything in the performance. My mistake was that I assumed that it would be a standard shaft diameter on all Swordfishes so make sure this is clear when purchasing!
It definitely offers more control as well when offshore and surfing waves but as Rob mentioned, you do need to be careful that you don’t apply too much kick as it will throw you off the wave.
Anyway, hope this helps and good luck!

Current Ski: Nelo 550 ML (4 WWR)
Previous Skis: Fenn Spark - carbon, Vajda Hawx elite, Fenn Swordfish - carbon, Fenn Elite - carbon

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13772 by Rightarmbad
I have been told that Think rudders can easily be made to fit a Fenn?
Both 8mm shafts, but you need to use a think tiller arm.

Don't know if this is true, but I sure hope so.
More fun things to mess around with.

Follow the path of the independent thinker. Expose your ideas to the dangers of controversy. Speak your mind and fear less the label of 'crackpot' than the stigma of conformity. And on issues that are important to you, stand up and be counted at any cost.--- Thomas J. Watson

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13774 by Kayaker Greg
Here you go, this was done by one of my fellow club members.

www.surfski.info/getting-started/tips-ot...udder-to-a-fenn.html

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13780 by gixer
Replied by gixer on topic Re: Swordfish elliptical rudder...
I fitted an elliptical rudder to my SF to help prevent stalling in big water. Unfortunately since then I have done limited paddling in rough water and have since switched back to the Dolphin rudder due to limited use. I did find that the elliptical rudder has a lot more drag than the standard dolphin rudder.
I purchased it from Carbonolgy SA (i'm in Australia), the guys were very helpful and dispatched the rudder asap. They only needed to know that it was to suit a SF and the rudder pin length. Apparently there are two different lengths in production.
I will put it back in for certain days as it only takes a few minutes to swap out.
Hope it helps.

Please Log in or Create an account to join the conversation.

8 years 1 week ago #13781 by Coffeephix
I too purchased a an elliptical rudder from Carbonolgy in SA. The guys there were great & really good to deal with. Unfortunately, I've switched back to the original shark fin rudder that was on the Swordfish when I got it. I recon the ski performs better with it.

Please Log in or Create an account to join the conversation.

Latest Forum Topics

New Allwave Skis (4 Posts)

1 day 1 hour ago
sarzelopez's Avatar

Video thread (453 Posts)

2 days 4 hours ago
kwolfe's Avatar

Installing Andersen bailer? (5 Posts)

3 days 13 hours ago
Protected by R Antispam