Monday, April 28, 2014

Cam Rotation

In this message I will discuss the problem of cam rotation and hopefully, provide some solutions.  In the previous post I mentioned Martin Cross and the problems he experienced with his new Overdrive.  He has just upgraded his Turbo for an Overdrive and where the Turbo rotated beautifully, the Overdrive sticks on the top two cams.

To save a lot of writing here is a copy of the e-mail I sent Martin:

Hi Martin

You are right about this being a common problem and I need to write a post covering this aspect of camber induced sail rigging.  My experience in this area has taught me to follow these steps to effect proper rotation of sticky cams. (Please forgive the rambling explanation):

 1. Ensure that if the inducer is an asymmetrical one, that it has been installed the right way up.         Sometimes the factory gets this wrong.  Just look at  how the cam sits on the mast.  If it is being pulled unnaturally, try rotating it and see how that works.  If the inducer is symmetrical - no problem.

 2. Give a bit more downhaul and see if this improves things. 

 3. Ensure that the cams are not getting snagged on loose protective tape (which Severne used on older masts).  This tape is quite soft and can distort and  bunch up where the cams make contact.  If the tape is snagging things - cut loose bits off and sand the area down. 

If the above measures fail, you are going to need to file the curved section of the cam down slightly.  This is the section which comes into contact with the batten pocket (NOT THE MAST!).  You will need a circular cross sectioned file (we call them rat-tail files).  Make a mark about 1mil from the existing curve edge and file the opening down until you reach your mark.  You are aiming to bring the cam away from the mast by enlarging this space.  The concave form runs the width of the cam of course so make an identical felt tip pen mark on either side of the cam and file down carefully until you reach both marks.  This can be a fairly long process as you shave the surface down, rig the sail and test the rotation. Repeat until the cam rotates nicely.  If you get one cam working properly it may just pull the other one round as it rotates but if not, then you need to repeat the process with the other cam.

The photo attachment indicates the cam surface I am talking about.  This is what you need to file down.

Please let me know how you get on

Here is the picture I attached to the mail:

Martin says that he is not that keen to start hacking away at his pristine new sail and I have to say that I understand this.  Cam filing should only be done as a last resort.

In a follow up e-mail, Martin mentioned something which caused my ears to prick up.  He said that he noticed when he de-rigged, that the bottom of one of the cams had gouged the mast (obviously as it rotated).  This opens up a really important further measure which I had not mentioned.  When you do your final downhaul after snapping the cams onto the mast, it is possible for the upward movement of the mast and downward movement of the sail to result in one or more cams being pulled out of alignment.  When this happens it compromises the cam's performance - the rollers do not sit squarely and so cannot do their job.  This can have two effects - firstly the cam in question does not rotate, secondly the adjacent cam can be prevented from rotating because it's mate is locked.  You then assume that both cams are faulty.  Wrong diagnosis!  Further, if one of your cams does settle in a missaligned position and you then force it round by kicking, head butting or punching (we've all been there), then what you get is a weakening and stretching at the cam/batten interface.  This can cause the cam to default to the incorrect position every time you rig and you can be left labeling your sail as "that damn thing which doesn't rotate".

The upshot of all this is - please ensure that all of your cams sit squarely on the mast before you hit the water.  This is really important for new sails.  You may just need to pull the cam slightly into the correct alignment to free it up.  This is crucial if you have one of the older red Enigma masts.  The protective tape on these masts is quite tacky and can easily snag your cams.

I hope that this post is useful.
Good winds

Thursday, April 24, 2014

Session Notes and Some Reader Feedback


We had some reasonable wind a while ago and I witnessed some really good performance from what I had thought was so-so kit.  The wind was not up to full strength and was still quite gusty.  In these conditions I sometimes take out my Cross 6.4 on a big slalom board (124l).  The board is super light and planes easily so the unlikely combo works fine until the wind picks up and I can change the board for our 116 3S and have some real fun.  The significant thing about the first combination is that it is unexpectedly fast and has the ability to spank serious equipment if the other rider is not top notch.

Anyway, Julian Field - a good sailor from Cape Town was on the water with his brand new 8.5 Phantom on a 79 Speedster with Z Fin .  He seemed to be going really well so I joined him for a few runs thinking that I would be able to run away from him.  No such luck!  I could almost hang with him but he was faster.  Jules is a good sailor as I said but I have never seen him going this fast.  The new 2 cam Phantom is absolutely awesome.  He had it pulled right down almost collapsing it and the result was some proper performance.  I am ambivalent about the 2013 Phantom ( 3 Cam) - it is too hard and racy for me but this new model seems soft, easy and very, very fast.  Jules has the old gold 100% mast.  The complete rig felt pretty heavy on the beach but we know that these are heavy sails, the masts are heavy too and his Pryde X9 boom is pretty chunky so no lightness anywhere but Jules recons that once on the water the thing is feather light in the hands.

Following on from this, Martin Cross - a reader, e-mailed me about his new Severne Overdrive.  Once he managed to rotate the cams he says that the sail was fantastic - light, easy and fast.  These two instances give me hope that the manufacturers are finally getting the message and creating some properly soft but properly fast performance sails.  Next season is starting to look good on the sail front.

Martin's problem was with the rotation on the new Overdrive and he suggested that I do a post about this problem and discuss some remedies.  This is a good idea since the rotation of cammed sails gives so many of you problems.  I will discuss Martin's actual problem in the next post, what I suggested and some of my thoughts on his case and the issue in general.

Talk to you soon  


Monday, April 14, 2014

The 7.8m Sail Question and Some Reader Feedback

Sorry for the long break.  A while ago Joos asked me for some suggestions about what to replace his 7.8m Severne Reflex with.  My current view is that for most of us, pure race sails are the wrong thing.  Depending on your brand loyalties, availability in your country, what your favorite supplier stocks etc - here are the models I would choose from:

  • Ezzy Lion 7.5  
  • North S-Type 7.8
  • Hot Sails Maui GP2 8.0
  • Maui Sails Titan GSX 7.5
  • Severne Turbo 7.5
  • Severne Overdrive 7.8
  • Avanti Condor 8.2
  • Ka Koncept 7.5
Since Joos is a Severne man through and through, my suggestion to him was the Turbo or the Overdrive.  Joos is not overly concerned with being the fastest guy on the water so he has opted for the Turbo 7.5.  A fine choice which will provide the low end power he needs on light days but also give a fairly wide window for when the wind picks up.  All of this comes in a super light package which should be light in the hands and easy on the body!  Personally I would have opted for the Overdrive for its extra performance.  I have always been against the Overdrive for being too racy but the latest pictures and the video of Sean blasting so easily along has changed my mind.  Severne has also made the sail compatible with both SDM and RDM masts showing that they understand the need most of us have for a softer performance sail.

I'm not too keen on the overhanging batten at the boom on both of these sails.  I'm also not keen on the fancy batten tensioners on the Overdrive but these things would not stop me buying either of these machines.  I await Joos's new sails (he has also ordered a Turbo 6.5) and will report back if I can scrounge a ride.

Reader Feedback

Kevin Do tells me that he rode one of the new Hot Sails Maui GPX sails and he recons that this thing smokes.  Kevin is a Ka Koncept rider so he knows what a fast sail is.  I have to say that when the GPX was announced it just looked right to me - simple, light and beautifully made.  I'm not sure how it would stand up against the Crosses in high wind but I think that it would do just fine.

Davide Verotta, a sailor from San Francisco commenting on the post regarding safety, says that a few of the San Francisco locals sail with VHF radios.  This is a really good idea because it enables you to communicate immediately with your mates and let everyone know what the problem is.  They can then organize among themselves what is to be done, who will do what etc.  Everyone is immediately and constantly in the loop and the situation can be resolved quickly.  The new water resistant radios are small and powerful.  What a great precaution!

On the new equipment front, I note that the new GA (Gaastra) masts are about to break cover.  The 100% carbon masts are dark blue now.  Look out for them soon.  We need to know whether the bend characteristics have changed.

OK - talk to you soon.  The wind outside looks quite good for this time of year so I am off for a sail. 


Sunday, April 6, 2014

Some Thoughts About Manufacture in Windsurfing

Before I deal with the 7.8m sail question, here is a technical post looking at the future of manufacture in our sport.  

The way boards and fins are manufactured has not changed since modern surf boards were made back in the 60’s.  Anyone looking around at modern developments in manufacture has to be questioning the way our industry continues to operate.  Despite the appearance of high tech scanners, 3D printing, unbelievably strong and light composites, we continue to design and manufacture fins, boards, masts and sails using the same methods used at the birth of windsurfing.

The business model has also become obsolete.  Take boards for example – a model is designed, tested and finalised.  The dimensions and material specs are then given to a central factory where the board starts off as a milled foam blank, composite and carbon fibre layers are applied using vacuum packing, heat, pressure and finally, labour intensive hand blocking to approximate specified shapes and dimensions.  The finished board is then shipped to a foreign country to be sold.
What should happen in a modern world is that the approved design is scanned into a file which can be e-mailed anywhere.  The file is used to produce the board where it is needed.  3D printing makes this possible.  The sticking point for me has always been that you cannot print with carbon fibre.  Without carbon fibre I am not happy.  Well a guy called Greg Mark has invented a method of printing with carbon fibre and with his team, has produced a printer to do this.  Yay!
Control/Click on the link below:

Their initial printer looks too small to print a whole board but the technology has been nailed so upscaling should be easy.  Just imagine being able to print off a few fins from your desk.  With this technology each fin will be exactly the same as the original, providing the recipe used is exactly the same.  You could have one shape with a few recipes - each giving a range of bend/twist/stiffness ratings.  Download the file and print the fins of your choice.  Awesome!

The moral dilemma around all of this is ensuring that designers get paid for their designs.  We have to retain the great designers and developers of our sport and will only do so if they can prosper within a new order.   Windsurfing without the likes of Kashy, Fagerholm, Vollenweider, Green, Zajicek, Spannier, Ezzy, Wentzel  etc, etc, etc would be very sad indeed.

Some food for thought

Talk to you soon         

Friday, April 4, 2014

"Rocket" Advert


This is a very short post.

Kevin Do drew my attention to a page on Starboard's site which refers to two tests on two of their models - Futura and Carve.  The wording on the picture refers to the Futura being a "real rocket" and this is simply a quote from the test result.  The way they have structured the illustration though, is definitely a dig at Tabou's Rocket and one can easily understand the thing to mean "The Real Rocket".

Very subversive, very clever and good for a chuckle.  Nice one Starboard!

Our season seems to be officially ending today.  Windguru shows no more sailable wind for the forseeable future.  Very bad

The next post will either be a piece on gybing or some commentary about the 7.8m sail dilemma for the normal sailor and how Joos has addressed this when choosing a replacement for his Severne Reflex.

Good winds