Report on Rs speed 50 failure

This is a continuation of a old thread .
A report has been done on my speedboard
That failed , this email was forwarded and no reply has
Been given after well over a month , I have since written to the ACCC

12th November 2014
Subject: Exocet speed RS 68 lit 235 x 50 cm
Date of inspection: 13/9/14
Serial No: EC13RSSPE5012070007
Nature of damage: cracked deck at tail section of board around back foot strap region

General approach: to investigate structural cracking of deck, in the region of the tail section of the board.
1. Visual observation, cracking of rails extending under rear foot pad region. Underside of board intact and not distorted by the deck cracking/bucklering (checked with straight edge as the board is reasonably flat in this area)
2. Remove rear foot straps & foot pads carefully to expose the extent of damage. The cracking extends the full circumference of the deck approximately 60mm in front of the back foot straps. At the top section of the deck the crack line has become a raised buckle profile.
3. Remove an outer laminate and core section of the deck through the cracked region to observe construction and nature of failure.
4. Looking at the section removed, it would appear that core and laminate is consistent with the general construction and manufacture of the board.
5. Personal observation: outer laminate construction double bias carbon fibre. Without further degradation to the board and an ash test I would assume the weight valve of the double bias is approximately 180 to 200gm/m2. There appears to be no other reinforcement in this area (AB & Carbon Art boards as an example have secondary carbon laminate reinforcements in all the foot strap/foot pad locations.
Consideration to the extra shock absorbing material under the foot pads would probably transfer load, thus perhaps removing some of the necessity of extra reinforcement. However due to the minimal cross sectional area of the tail and the change of outline profile relevant to the scalloped out profiles to accommodate the extra shock absorbing material, this develops a negative less structural outline profile. The other concerns would be that although double bias reinforcements provide high stiffness due to the fibre tows are stitched on top of each other so when load is applied to the laminate these filaments are already straight unlike a woven cloth. The negative to this is that without a woven cloth over double bias it has a tendency to strip or buckle and delaminate when load is applied. A good combination in this region would have been using a combination of double bias and woven cloth, they actually complement each other and the extra thickness is also a function of extra stiffness.
Another question regarding the choice of double bias at 45 degrees over the length of the board doesn?t promote longitudinal stiffness. If it was a wave board it would be less concerning, however longitudinal stiffness would be more suitable for slalom and speed boards.


6. My personal thoughts regarding the construction of the board is that it is consistently manufactured, however very on the edge regarding laminate structure. Using this board in the normally high wind conditions if you were a reasonably sized person I would expect to damage it. Using double bias at 45 degrees over the length of the board and the scalloped out profiles to accommodate the extra shock absorbing material in the minimal cross sectional area of the tail suggests that this board is less structural in this region than other production boards in the market place. There is no evidence in paint work or markings on the bottom to indicate a major running aground or hitting anything submerged. I don?t think it would have taken much force to inflict this damage as the laminate on the deck from the edge of the rails buckled and tore partially due to orientation of fibre and thickness of overall laminate. The bottom of the board would have gone into tension and was left intact.
7. I believe the board can be repaired, however due to duty of care it?s important that the repair is affective given that failure in this region of the board could inflict major personal injury.
8. Method of repair:
? Mask up board
? Grind & feather damaged laminate & prep for existing laminate repair
? Laminate prepared region
? Sand & fair repaired laminate
? Fit hi-density foam to scalloped profile & bond
? Reshape hi density foam to outer sectional profile of the tail of the board
? Prep & remove necessary paint in the tail section of the board
? Laminate 200 gm twill carbon over the hi density foam inserts & tail section
? Sand & fair & fill repaired laminate
? Re mask tail section & epoxy hi build prime
? Sand & fair & fill painted region
? Spray final primer
? Sand & fair & fill painted region
? Final gloss /match existing paint work
? Re mask foot pad region /paint with clear polyurethane & non-skid
? Remove shock absorbing material from original rear foot pad
? Mask & use contact adhesive to replace original foot pad
? Replace foot straps & general cleanup
? Include already committed time regarding accessing damage & preparing report
? Estimate materials & labour $350 to $400.00
Please find photos attached

Regards

Shipwright

I have purposely left the guys name out

What was the part about the repair in that area being able to cause major personal injury? Maybe just a little over the top don't you think?
In the time it took your "shipwright" to do that massively letigious damage report he could have just repaired the thing and had you back on the water for around $200.
Maybe the board was built too light but that all seems like a whole lot of messing around and game playing to me.
Just get it fixed and go sailing.

it's a 2013 board, how long do exocet warrant their boards ??

Firstly I obviously don't like discussions like this on a forum or in writing mostly because it leaves things open to interpretation (reason why we called the customer a number of times after exchange of emails), but I will try to give some further insight into the concerns and statements made since we were made aware of this case:

- The board is a 2012 design, grey and purple graphics
- The warranty is between the customer and us, not with Exocet
- The customer was called about 10 times since we were made aware of the issue (a bit disappointing to hear back from him today)

- Sailing in shallow waters (less than knee deep) represents risks and as such people need to be aware and accept the consequences
- The board hit bottom during a jybe which is consistent with the type of failure (compression failure under point load) and not considered normal use

- Evolution of the performance boards (slalom boards mainly) and mainly the demand of pro riders drive for less weight within an acceptable weight/strength ratio (Pro riders compete on production boards for slalom)
- As far as we are aware there is a number of these RS boards on the market since 2012 and still going strong
- Exocet is continuously learning from market feedback and its R&D and improves on previous design wherever is deemed necessary

I hope this helps with some of the concerns. If some wish to discuss further feel free to PM or call.

Thanks Remi

I've recently helped repair a board here with a similar problem. Hit a rock at speed with a delta fin. The extreme rake of the delta is great in weed, and at first thoughts, shouldn't be too bad when it hits something.
You'd think it would tend to just slide up over the obstruction, without coming to a dead stop, like a vertical fin would.
But I now realise there's a very big vertical force just behind the rider, so the chance of a compression failure around the footstrap area is very high, no matter how good the construction.