RS400 proposed changes

Hi all

I just want to clarify on a couple of points and get back to the main topic.

The original concept of having a tapered spinnaker pole was to aid the launch system  on a single line hoist. The original new spec spinnaker pole which we tested significantly,  had a ration of 40% carbon against glass. The reason why we went  down this route was to keep costs sensible as we had to retain a similar weight to the aluminum pole. 

This pole was very much designed purely for the RS400 and we tested it over many  months of sailing in all sorts of conditions and got feedback through many sailors without any problems.  All the static load tests compared to the aluminum pole made us happy to put this into production.

The problem occurred when we under estimated the uniform  shape of existing pole mouths on existing boats when swapping over from aluminum to carbon poles. Most of the breakages occurred when the pole was set in the middle of the pole mouth during certain  high wind conditions where the spinnaker was allowed to flog, the inertia of the pole bending around the mouth led to point loading where the pole exits, and this was enough to break the pole.  

I agree with Kev M comments -  May be by  a trial  on a few boats over the  year,  this problem might of been more apparent.  As i said before the static load tests showed great results and we didn't have a reason to doubt this along side the information we gained by  the sailing we had done. I guess thats hindsight for you.. and  we should learn on this.

We went through many  ideas and options to sort the problem, but  felt the best way forward  was to replace the poles we had delivered,  with a higher content carbon tube,  to increase the strength  add we added a nylon internal bulkhead to reduce the compression, the simulations which we did saw a dramatic improvement.

This  bulkhead was positioned internally at the point where the pole exited the bow when the sprit was fully launched.  We felt this was the better option than trying to retro fit all the boats with a tube enlarging the  bearing surface, as we were concerned about introducing a further problem as the pole needs to gype from side to side.

Since then we have had unfortunately a  further problem. There was an issue with a  bad batch of glue which was used to hold in the nylon bulkheads. In some very few instances the glue has failed and the bulkhead has been able to slide back  effecting the lack of support around the pole exit once again. 

I just want to stress at this point - The movement of the internal bulkhead has only happened on a small number of sprits and I'm confident it does not effect the majority of them. 

We are not taking any chances on this matter,  and we are just about to start a program  with CA in checking all bowsprits as we really want this problem to reach a complete conclusion before the start of next sailing season. Since introducing the bonded in bulkhead the problem has been resolved.

Could we of done things differently, for sure..... but we are actively sorting it out.

Please contact me directly if you have any concerns on the Spinnaker pole on :-  alex@rssailing.com

many thanks

Alex