GGR 22

[savageseadog]

Would you consider re-rigging an old wooden pilot boat with modern stainless wire and bottle screws etc. Maybe you would but IMO you would be asking for trouble doing that on a basic structure that had already see 60 years of use. This could well be the same thing - a grp hull that wouldnt have been built to modern high strength standards now subject to high rigging loads and whats more being pushed in a race. And as for testing the basic structure there is not much more available than the surveyors experience and NDT tools like moisture meters.

Like you I dont know what has happened and I might well be miles off the mark but if modern high tec hulls can be overstressed whilst racing how much more likely a 60 year old hull.

I think a full scale structural failure is unlikely. Those old boats are built like brick outhouses from solid glass. Unless those mods weakened the hull somehow. The rig size was decreased, this will reduce rig loading despite the increase in wire size.

 

[zoidberg]

There's only about 21 nm between Abilash and Kirsten at 2000hrs tonight/Thursday,. and he is closing on her track from the north.

That 'DTG' is calculated simplistically using Great Circle calculations - not, as far as I undertstand, corrected for the Modified Great Circle routes they are following to avoid ice zones...... so, they may be closer to neck-and-neck.

Edit: Just noticed a 'letter' from Tapio on board his rescue ship, on the GGR news page. Not a word about 'why/how'.

 

[Sandy]

I was thinking self steering was a good candidate for something which could rip a big hole in the stern area.

Then I read this. Interesting analysis - still conjecture though, as everything will be!

Thanks for posting that link to the blog @jlavery .

Peter Foerthmann makes some really good points. While I am not a structural engineer or nautical architect I can cast an ''engineer's eye' over most things and have a liberal dose of common sense, but who thought that transom would be big enough to support a Hydrovane with two attachment points, the lower one at the join between the transom and the hull? Why no tripod to support the Hydrovane, this is Year 10 physics. The answer is in the photographs, there is no space to fit a tripod.

Tapio has taken the lessons of the 2018 event, Hydrovanes work, but failed to implement them correctly for his boat. I have spoken at length at two boat shows with Will Curry about fitting a Hydrovane on my boat and know he is extremely knowledgeable about his product. It would be interesting to see what discussions were had with the company on this set up.

 

[capnsensible]

Another retirement. Been coming for a while, Arnaud has rigging problems and barnacle drag. Heading north to St. Helena then homeward bounders to France. Good effort though.

 

[Paulfireblade]

I think all the entrants are totally bonkers but incredibly brave. I have been following the GGR this year and only just stumbled across this thread but fascinated by all the theories of what caused the sad loss of Tapio’s boat

 

[Frank Holden]

Another retirement. Been coming for a while, Arnaud has rigging problems and barnacle drag. Heading north to St. Helena then homeward bounders to France. Good effort though.

Barnacle Drag??? Aren't they allowed to use antifouling??????
I've done extended passages - both in time and distance - and never had 'barnacle drag'.

 

[Birdseye]

I think a full scale structural failure is unlikely. Those old boats are built like brick outhouses from solid glass. Unless those mods weakened the hull somehow. The rig size was decreased, this will reduce rig loading despite the increase in wire size.

I agree. But dont be deceived by "brick outhouses from solid glass" - in the early days of grp, much of the thickness was down to fillers like talc, the resins werent that good and neither were the glass matts. Plus grp like everything else has a fatigue life. How much has been used in the intervening years.
Sandy makes a good point.

 

[capnsensible]

Barnacle Drag??? Aren't they allowed to use antifouling??????
I've done extended passages - both in time and distance - and never had 'barnacle drag'.

You were lucky. ?

Lots of the fleet are having big problems with goose barnacles. Happened last race too. Lots of online stuff in the GGR history.

Mebbe it's climate change? Who knows. I had a big problem with them on a yacht in the Pacific. We had the usual inspection in The Galapagos, quite clean. A week or so further west, they were growing. By the time we got to Tahiti, infested. Was 5 years ago.

 

[Sandy]

Barnacle Drag??? Aren't they allowed to use antifouling??????
I've done extended passages - both in time and distance - and never had 'barnacle drag'.

Antifoul is only a recent invention, in the McIntyre world.

My prize for the 'comical requirement' of the circus is you can only use music cassettes! As if a MP3 player is going to give you an advantage.

 

[Frogmogman]

We will never know what happened to Tapio's boat, but please indulge me while I explained my diagnosis.

Here are the background facts:
The boat was manufactured sometime in the late 1960s or early 1970s. It was designed by Sparkman and Stephens similar to the Swan 36. Note the counter stern.
Tapio's boat had heavily upgraded rigging, including a shortened mast and much heavier stays. It also had multiple headstays.
The boat sank rapidly after a bang, with no mention of collision shock.
View attachment 146538
Now for my theory.
One of the first engineering principles I learned as a teenager building model aeroplanes, was that reinforcing a structure can throw extra load onto other parts of the structure. It also taught me about stress concentrations.
Creating stronger rigging and a stronger mast allows for much greater tension forces in the rigging. These tension forces create a bending moment on the hull, with upward loads at the bow and stern. Now look at the drawing of the similar Swan 36. Note the potential stress concentration at the end of the counter and the rudder post. The counter is also small and narrow.
The Southern Ocean is cooler than the late summer temperatures that would have been experienced at the start of the race. Lower temperatures would result in rigging contraction and even higher tensions. It is unlikely that Tapio had a chance to retention his rigging at sea. So much higher loads were placed on an old hull, not designed for them.

So my theory is that the increased tensions on the rigging due to all the above factors, and the age of the boat, led to a fatal crack in the hull, probably at or near the rudder post.

So that's my theory, and as Donald Trump would say, "only saying"....

Your theory reminds me of the time we installed a new hydraulic system on FCF Challenger when it had been converted to a masthead rig after its first Whitbread. We really cranked up the backstay tension, then could hear a banging noise from below.

It was Les Williams who was stuck in the heads, banging on the door whose frame had been compressed at the top by the boat banana-ing.

Longitudinal composite I beams were then glassed in under the deck…..

 

[Yara]

The more I think about Tapios boat the more I believe the deck hatch holes created the conditions for compression failure.

 

[boomerangben]

Just dipped into this and read some of the supporting threads re Tapio’s tragic exit from the race. I doubt there is a single failure here, rather the chain reaction that normally accompanies such a catastrophic loss. Perhaps the lower hydrovane attachment failed, weakening the hull structure, and higher rigging loads compounded by heavier mast and rigging (increased inertia loads through vessel movement) combining so that stresses within the hull shell are higher, causing at some point a crack that propagates rapidly and extensively beyond the two new bulkheads….. who knows. But I admire the competitors for their pioneering spirit (yes I know it’s been done before but there is no rule book as far as I know on designing these boats so they are all prototypes) and of course grateful to his rescuers.

 

[RunAgroundHard]

The more I think about Tapios boat the more I believe the deck hatch holes created the conditions for compression failure.

Can you explain what the "deck hatch holes" are and why you think they were subject to excessive compression loads? The reason I ask, is that i may cut two holes in my aft deck, for gas bottles storage, so interested in why you think that.

 

[Yara]

Can you explain what the "deck hatch holes" are and why you think they were subject to excessive compression loads? The reason I ask, is that i may cut two holes in my aft deck, for gas bottles storage, so interested in why you think that.

High rigging loads place the hull in tension, and the deck in compression. Take a look at this link Tapio Lehtinen | Windpilot Blog EN
Tapio was concerned with leaks from through-hulls, so he made multiple bulkheads, with access from big hatches cut in the deck. Solved one problem, created another. You can see the hatches in the above link. If holes are small, and reinforced by strong flanges, usually not a problem. However, whenever you cut a hole in a structure you are going to weaken it. There are modern CAD stress programmes to analyze the structure, but us old engineers use the Mk1 eyeball.

 

[RunAgroundHard]

High rigging loads place the hull in tension, and the deck in compression. Take a look at this link Tapio Lehtinen | Windpilot Blog EN
Tapio was concerned with leaks from through-hulls, so he made multiple bulkheads, with access from big hatches cut in the deck. Solved one problem, created another. You can see the hatches in the above link. If holes are small, and reinforced by strong flanges, usually not a problem. However, whenever you cut a hole in a structure you are going to weaken it. There are modern CAD stress programmes to analyze the structure, but us old engineers use the Mk1 eyeball.

Interesting link. I notice that the original hull flange and deck flange that runs right around the hull has been cut right through to remove the deck (only way it could be removed). You can see the original deck to hull join remains in place and is still bonded on the pictures. On my boat, that hull flange is 12" wide, running right around the boat, about 3" below the gunwale and is a minimum of 25mm thick (larger boat at 41'). The deck was bonded onto it, like the original deck in the link, with the outside deck edge turned up to form the inside of the gunwale. I originally rejected the holes in my aft deck as they would cut through this flange.

It would be interesting to understand how he bonded the deck back to the hull. If that was not done properly, or was lightened, then perhaps the hull actually separated from the deck due to a join that was not strong enough. Maybe there was big lap joint that bridged the two sections, deck and hull joint, some of the bulkheads don't look as if they have been cut out to allow a lap joint to be added, maybe later this was done, also see the most forward bulk head has shelf on it. Certainly the boat was not built that way originally, as the deck edge and hull both contributed the final gunwale and would have been glued together to give a degree of form stiffness, in addition to the hull flange and deck flange being glued together. The stress raisers from the shrouds and running back stays, are all on the original deck / hull flange that was not cut out. Hence, the new hull to deck joint, somewhere inboard, would now have to manage these stresses. I would imagine that any new join would be a critical design feature to resist the strain.

I doubt that we will ever know. That amount of alteration and adjustment I assume would be signed off by a naval architect and the reinstatement verified through a QA/QC process, to ensure hull integrity was at least as good as the original design. I don't think that "Mk1 eyeball" would cut the mustard on this. Anyway, glad ws rescued and was safe, which is the most important point. I do hope that there is a thorough review into the refurbishment of the boat and a causal analysis method applied to try and understand what actually happened. I think you would not need to boat to get to the bottom of the failure if the refurbishment facts are known.

 

[zoidberg]

Interesting that Simon Curwen's 'Biscay 36' is doing so well in the GGR.

Here's an interesting review of some of its characteristics: Biscay 36

 

[flaming]

Interesting that Simon Curwen's 'Biscay 36' is doing so well in the GGR.

Here's an interesting review of some of its characteristics: Biscay 36

Having raced against Simon in the J105 fleet for a while I would posit that anything Simon was sailing would be doing just as well.....

 

[zoidberg]

Kirsten has just put in a 179nm day.... if the Tracker is to be believed.
That's an average of 7.45kts..... which is remarkable. She has ~826 nm to make up.

 

[jlavery]

Having raced against Simon in the J105 fleet for a while I would posit that anything Simon was sailing would be doing just as well.....

I agree - his pedigree of 2nd in the Mini Transat and 2nd in class in the Fastnet (among other results) show that he knows how to race a boat efficiently - a skill which I think others in this race lack (apart from Damien Guillou).

 

[r_h]

I agree - his pedigree of 2nd in the Mini Transat and 2nd in class in the Fastnet (among other results) show that he knows how to race a boat efficiently - a skill which I think others in this race lack (apart from Damien Guillou).

+1 especially when you look at who he shared the Mini Transat podium with - Yannick Bestaven and Arnaud Boissieres