DRAGONFLY Trimarans User Forum

What a mess!

http://www.knrm.nl/30waar_wij_zijn/10re ... icle=13979

Anyone have an inside report? Looks like the forward beam is connected to the hull but no longer to the float. (Part of) the rear beam is still attached to the float.

Article is in Dutch I believe.
The translation wasn't that great on Google.
If I was to bet on what went wrong, I would guess the water stay broke.
The article did say that the two people on the boat were ok.

Ted

I do speak Dutch.

Force 6, not too much. Article states one float broke off/loose and boat capsized. Rescue teams were out already looking for missing racer which they had just located, no emergency there, so they quickly went to the tri. They tried to right it, but in that process it dismasted. (we know why). It was towed in all but submerged after which it was pumped out.

No further details.

Rumour has it that there was a structural failure other than broken waterstay or forgotten safety strut. Possibly a broken beam or hinge.

Last wednesday a friend saw it passing by on a truck heading north on the A7 so i'm guessing its headed for Denmark for investigation.

Hey Ipe, jij in Medemblik? Vriendje van mij is havenmeester daar....

Welke haven? Ik lig in het regattacenter.

Hij was havenmeester in de Pekelharing haven, maar de gemeente heeft die aangelsoten bij de andere gemeente havens, dus hij zit nu in het torentje tussen de Westerhaven en de Oosterhaven.

Dear Ipe and Oscar.

I'm lucky enough do understand what your discussion is about but I still think if would be better to stick to English so all members understand the messages.
Thank you for your understanding in this matter.

Roger that.

There's a report of the incident by the owner of the unfortunate ship in our dutch multihull club magazine 'CTC nieuws'.
He was sailing at a speed of 11 knots in wind about 20 knots, 1 reef, slight to modest wave action. Suddenly a spontaneous breakage occured in the front starboard beam, shortly followed by the rear beam and capsize follows. Total timespan about 5 seconds.
Investigation afterwards reveals that both waterstays are still intact and mounted properly. So primary failure seems to be fracture of the beam. Very remarkable fact: this was a new beam, mounted at the start of this season! Story doesn't tell why a new beam was necessary.

...other sources tell me they doubt this story. They think that the primary failure was the swing wing line. Folding occured, then fracture and total collapse. Let's hope that investigation will clear this up!

Hi !
The story is very similar to the df35 that broke last year here in Denmark - in this case it was the front line which should prevent folding that wasn't in the right place !
/anders.

There is no such frontline on a 'common' 920 - you will only find it on the Extreme.
I wrote Jens Q mid October but he were not able to tell anything until the cause is fully determined and cleared with the owner.
We hopefully can look forward to an explanation from Jen Q soon

//Henrik

Ipe Piccardt Brouwer wrote:...other sources tell me they doubt this story. They think that the primary failure was the swing wing line. Folding occured, then fracture and total collapse. Let's hope that investigation will clear this up!

If this is the case I have got one solution to prevent this:
http://www.dragonfly-trimarans.org/phpB ... =1161#1161

Hi Mika - the drawings were not attached - please send them to me on henrik@voldsgaard.com
Thanks

//Henrik

Why would failure of the swing wing line cause the float to fold back? Surely the point of the pin in the tube brace between the main hull stern and the aft beam should stop the folding??

Hopefully you are right, but the truth is, that we can produce hypotheses from now on to christmas evening.
I think it's time for Quorning to comment on this issue!

Another way to go is contacting the 920-owner directly. Is there anyone who has contact details? What about our Dutch friends? Maybe it is possible to get a copy of the survey report.

I'm curious

//Henrik

I've now attached the drawing to Mika's message (see above).
An interesting and simple idea!

Mal wrote:Why would failure of the swing wing line cause the float to fold back? Surely the point of the pin in the tube brace between the main hull stern and the aft beam should stop the folding??

This is bigger problem with DF1000, because the tube length/diameter/thickness ratio is worse.
If DF1000 is flying two hulls and the SwingWing line breaks down I would like to be somewhere else without a backup system .
From engineering point of view the original tube might not be robust enough.
DF920 has shorter tubes so the problem might be smaller, but anyhow DF920X has similar system as backup.

Looks OK, but isn't a line from the end of the front crossbeam to the mooring cleat each side of the bow easier? There's too much friction via lines in the folding system anyway, wouldn't want to add any more dragging lines and blocks.

I sail across Swansea Bay on my way back to port, passing all the monohulls. I enter the river ready to lock in, and whilst I am winching in the floats and folding, all the monohulls catch up, pass me, and go in the lock before me! Ce la vie!

Mal wrote:Looks OK, but isn't a line from the end of the front crossbeam to the mooring cleat each side of the bow easier? There's too much friction via lines in the folding system anyway, wouldn't want to add any more dragging lines and blocks.

I sail across Swansea Bay on my way back to port, passing all the monohulls. I enter the river ready to lock in, and whilst I am winching in the floats and folding, all the monohulls catch up, pass me, and go in the lock before me! Ce la vie!

My backup system is completely independent. It is not using the original SwinWing lines or blocks anyhow. The direction of the rope (and force) is better in my system to hold the floats open if something goes wrong.

Ipe Piccardt Brouwer wrote:Rumour has it that there was a structural failure other than broken waterstay or forgotten safety strut. Possibly a broken beam or hinge.

Last wednesday a friend saw it passing by on a truck heading north on the A7 so i'm guessing its headed for Denmark for investigation.

Hope we shall have a complete report of what happened from Qorning!