GUNBOAT Dismasting

[GoingWalkabout]

Ok. What do we know.

1. Question now exists over the design of the mast rigging
2. Questions raised about the overall design of GB 55
3. Captain chose to sail off into a storm
4. Captain did not have a sea anchor ready
5. Captain did not have a drogue
6. Questions raised about the sailing sense of the Captains sheeting decisions
7. Questions raised about the Captains sailing decisions at the time of the event
8. Questions remain about the structural integrity of the boat in rough seas
9. Questions remain as to why the GB 55 travelled so slowly over distance prior to the dismantling
10. We do know that the automatic sheet dump did them no good
11. We do know that the GB 55 failed in a storm
12. We do know that almost every person to a sailor would not have gone out in the weather they did
13. We do know they abandoned ship without leaving any tracing device - What we don't know is why.
14. We do know they were preparing to flee the stricken boat for a life raft - What we don't know is why

This is only a short list. I am sure others could add too it.

Perhaps the Captain, crew, passengers and boat builder can answer the above questions. I do understand if these aren't answered given the bad light this could shed on the boat.

In the meantime the latest attempt by the boat builder to point the finger at a component manufacturer is pretty obnoxious in my opinion. Typical tactic in this day and age.

Finally since the boat builder has already said the Captain is going to make a full report I have one other question. What is taking so long?

[SVNeko]

Originally Posted by Dave852

I would do the same thing, that's what you do on a cat when caught in a situation with to much sail up. You never round up in a cat, just increases your speed and therefore the apparent wind speed. A cat turning up is powering up. When you turn downwind the apparent wind decreases and by keeping the main sheeted in he was in fact further de-powering it as the wind came around behind him. So to summarize he did not turn downwind to furl the jib, he did it to de-power the boat. Sadly when the story of the Atlantic 57 was recounted they were rounding up and blowing sheets prior to the capsize. This is a monohull tactic which is all to often carried over to multihulls, I believe due to the fact that the majority of sailors learned how to sail on a mono. Just replying to a specific comment, sorry to interrupt the thread as I definitely have nothing to say about the Gunboat loss.


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I'm sorry, I agree with Palarran. They were close reaching. In that situation, much easier to ease off the jib, pinch up and luff and then reef. Bringing the wind around on that trim would power up the boat just as you suggest. I would agree with you if they were sailing off the wind more.

[Jon Eisberg]

Originally Posted by SVNeko

I'm sorry, I agree with Palarran. They were close reaching. In that situation, much easier to ease off the jib, pinch up and luff and then reef. Bringing the wind around on that trim would power up the boat just as you suggest. I would agree with you if they were sailing off the wind more.

One thing I found baffling in that account from soma, was his use of the phrase "nondescript squall"...

Really? At night? How does one determine exactly whether in fact a squall will be "nondescript", at night, which proved not to be the case in that instance, anyway? Is that a prudent mindset, when sailing a high performance multihull like a Gunboat?

Similarly, in Johnstone's initial account of RAINMAKER's dismasting, he stated there was "no indication" that the squall that took the rig down would be any more than the series of 40-knot squalls they'd encountered
previously... And, that all occurred during daylight hours... Yet now, we hear it was a "total whiteout squall", perhaps even a waterspout...

One of the adages that Don Street continues to repeat, is that even after more than 60 years of sailing in the tropics, it's extremely difficult to accurately assess the amount of wind any particular squall might contain. I expect that goes double for after dark... But, of course, few people listen to an old dog like Street, anymore - that guy's a dinosaur, if there ever was one... ;-)

I still can't fathom carrying a triple reefed main thru 40-knot squalls (more likely closer to 50 knots TWS, in the cold, denser air of January), while sailing into a "large South swell"... But, sailing a Gunboat 55 is light years beyond my pay grade, anyway, I'll leave that to the Gunboat Bull Riders like soma...

[Jon Eisberg]

Originally Posted by Going Walkabout

Ok. What do we know.

1. Question now exists over the design of the mast rigging
2. Questions raised about the overall design of GB 55
3. Captain chose to sail off into a storm
4. Captain did not have a sea anchor ready
5. Captain did not have a drogue
6. Questions raised about the sailing sense of the Captains sheeting decisions
7. Questions raised about the Captains sailing decisions at the time of the event
8. Questions remain about the structural integrity of the boat in rough seas
9. Questions remain as to why the GB 55 travelled so slowly over distance prior to the dismantling
10. We do know that the automatic sheet dump did them no good
11. We do know that the GB 55 failed in a storm
12. We do know that almost every person to a sailor would not have gone out in the weather they did
13. We do know they abandoned ship without leaving any tracing device - What we don't know is why.
14. We do know they were preparing to flee the stricken boat for a life raft - What we don't know is why

This is only a short list. I am sure others could add too it.

Perhaps the Captain, crew, passengers and boat builder can answer the above questions. I do understand if these aren't answered given the bad light this could shed on the boat.

In the meantime the latest attempt by the boat builder to point the finger at a component manufacturer is pretty obnoxious in my opinion. Typical tactic in this day and age.

Well, I've certainly done my share of "speculating" about this incident, but I would suggest we still do not "know" many of those things on your list...

"Questions raised", or "questions remaining" about certain aspects of this story, for example, hardly rise to the level of something "known"...

And, things like sea anchors and drogues, for instance... How do you know at this point, whether such gear was, or was not, being carried aboard RAINMAKER, or whether their use might have been considered, or ruled out for any possible number of reasons?

Originally Posted by Going Walkabout

Finally since the boat builder has already said the Captain is going to make a full report I have one other question. What is taking so long?

As already noted by others, waiting for the check from the insurers of RAINMAKER to clear, would seem to be as good a guess as any...

[GoingWalkabout]

Originally Posted by Jon Eisberg

Well, I've certainly done my share of "speculating" about this incident, but I would suggest we still do not "know" many of those things on your list...

"Questions raised", or "questions remaining" about certain aspects of this story, for example, hardly rise to the level of something "known"...

And, things like sea anchors and drogues, for instance... How do you know at this point, whether such gear was, or was not, being carried aboard RAINMAKER, or whether their use might have been considered, or ruled out for any possible number of reasons?



As already noted by others, waiting for the check from the insurers of RAINMAKER to clear, would seem to be as good a guess as any...

I agree. So lets ask the Captain.

[Delancey]

Originally Posted by Polux

Regarding the mast hall spars makes masts with different specifications. The ones that choose the mast and the specifications were the boat designer and eventually Gunboat shipyard. The rigging of the mast has not to do with all spars but with the ones that designed the rigging on Gunboat shipyard. It could have been made in association with hall spars or independently.

I will be interested to see where the how the cookie crumbles on this one as I doubt either the boat's designer or builder were telling a specialty sub contractor with more than twenty years of experience building carbon spars how they should build their masts.

Maybe what you suggest is true with when dealing with stock alloy extrusions but I am not so certain when it comes to mass-customized carbon spars.

My relevant experience comes from working for a specialty sub-contractor designing and fabricating highly creative architectural ornamentation and public art projects. We did a lot of crazy things that hadn't been done before and the end of the day it all came down to the stamp of our P.E. to ensure these things didn't tip over or fall off a wall a kill somebody, not the architect or the designer.

I imagine there is a fair amount of back and forth between the designer, GB, and Hall Spars when working on a project like this. There has to be. The mast on this boat wasn't just lying around in a shed somewhere when they designed the boat and somebody said "oh, maybe we can make this one work?"

This mast was designed for this boat and it was designed by Hall Spars, not by the boats designer or GB.

Sure the designer "spec'd" it and the builder accepted it. But both relied on the unique expertise of the manufacturer to develop the specifications. They didn't tell the spar maker how to tailor their lay-up, how to design the sheaves, or whatever. All they did was give Hall Spars a sail plan and a bunch of numbers and said give me a mast. Hall Spars did the rest.

Trust me when I say scuppers drain on the low side.

For clarity, I'm not Hall Spars bashing. I think they are a great company with nice people and quality product. Things happen when you push the performance envelope. In this case the rig failed. The boat and crew survived an event that might have otherwise ended much worse. Life goes on.

[Dave852]

Originally Posted by SVNeko

I'm sorry, I agree with Palarran. They were close reaching. In that situation, much easier to ease off the jib, pinch up and luff and then reef. Bringing the wind around on that trim would power up the boat just as you suggest. I would agree with you if they were sailing off the wind more.

Ok, if it was a slow enough cat and or the squall came with a wind shift favorable to your argument I could see your method working. But let me be more descriptive. Let's say close reaching means sailing 45 degrees off the apparent wind. And let's also say we are discussing fast catamarans. Now let's say we are close reaching in the fast cat in 18 knots of true wind. At what angle do you suppose the true wind is at? Well I am sure someone with some math smarts will be able to calculate that if they had all the data needed but for the sake of this visual let's say the true wind is at 85 degrees when a 50 knot squall hits with no direction change. For a second until the boat speed increases the apparent angle will increase. If your instinct is to bear off you will only have to turn though 10 degrees or so before she starts to de-power but if you decide to head up you have a long way to go and in fact will power up before ever getting there.
Your boat, while not a gunboat and depending how much weight you are carrying should be able to mimic this scenario as she is capable of a turn of speed. Next time you are sailing fast enough to bring the apparent wind forward try bearing off and then bearing up. See which one gets you to a calm place faster!


Sent from my iPad using Cruisers Sailing Forum

[Sand crab]

Originally Posted by 44'cruisingcat

Fair enough, as I said, I haven't seen one. Although now I think of it, I have seen a completely unstayed carbon mast.

There was a recent link to a cat with a (rotating?) unstayed mast that was for sale in OZ in one of these forums. It was a large custom build. It was setup and possibly designed with only the main so there were no head sails but then that would be a stayed mast. I can't remember if it was a carbon mast though and can't find it now. It seems like it was on a local FSBO site and not a brokerage but I could be wrong on that. Maybe you guys downunder will know where to look.

[neilpride]

The big concern to me is why Hall Spar design the mast without lowers!! and just a single set of sweep back spreaders.... just wonder?

[Southern Star]

Bearing off while letting out/releasing the sheets is the best way of avoiding capsize/strain on the rig when suddenly overpowered while sailing a cat on a close reach/beating. There are three reasons:

1. As has been pointed out, if you head up the apparent wind increases, thereby effectively increasing the force of the wind on the sails. Conversely, if you bear off, the apparent wind decreases, thereby effectively reducing the the force of the wind on the sails.
2. The force generated by a sail is typically about 15 degrees forward of perpendicular to the boom, or foot of the sail. That is why boats heel more when sheeted in and sailing close to the wind (more of the force generated goes to the side -i.e., towards heeling, than forward). Conversely, when reaching/the sails are let out, more of the force generated by the sails is directed forward, rather than to the side. This results in less heeling even with equivalent force of wind on the sails. Until you are luffing, heading up will only move more of the force on the sails to the side and increase heeling.
3. As you turn up, the centripetal force will tend to increase the roll to leeward, further increasing the risk of capsize (think of the sway/roll of a car away from the apex of a tight turn). If you were in a jeep which started to lift its inside wheels in a tight turn, would you continue to turn up, or turn away in order to bring the inside wheels down? Same thing with a cat.

Therfore, when suddenly and dramatically overpowered when sailing on a close reach or beat, in order to avoid capsize one should let off on the sails while steering to leeward. This, of course, may make reefing/dropping the sails more difficult in the short term than successfully heading up into the wind. However, if the boat capsizes while heading up, you will no longer have the opportunity to reef or drop the sails at all!

Brad

[Stumble]

I have read pretty much all the speculation available at this point, and the very little amount of actual facts. But have tried to stay out of it.

However I have come to a preliminary conclusion that the most likely failure method is just a simple design error in the mast. My internal story is pretty much the following...

The boat was fast reaching under tripple reefed main and jib when it crashed at high speed into the back of the steep short waves found in this area. This placed a huge bending load on the mast at exactly the weakest point of the construction. Specifically the unstayed area at the spreaders. This rapid deceleration combined with high bend loads was beyond the capability of the mast and it snapped.

The major alternate story is that the mast could have been designed for this but there was a failure in the layup. It wouldn't have taken much contamination in the pre-peg to result in a bad section, and it happened at exactly the right spot the mast would have been under design spec. However I find this an unlikely failure mode without some evidence to support it.

The solution of course is that GB will need to replace the masts on the rest of the GB55's and likely do some destruction testing of the mast sections. But I really don't think this dooms the entire line. It is a teething issue (albeit a major one) that can be worked out.


Finally as to the silence from the principles. As an attorney I can promise you no matter what happened the first thing to do in this type of case (actually almost all cases) is to prevent any disclosure of information until you have a good picture of what happened. It doesn't even matter if the speculation is in your favor or not at the beginning because even baseless supposition from a principle can be deadly in front of a jury.

keep in mind that no matter what, someone is likely to loose their job over this. If it was the rig designer that under specced the mast then he will be gone. If it was the project engineer that gave the mast designer the wrong numbers the PE is gone. If it was someone at Hall that messed up they are likely to be fired. These are all high value positions and if they are fired wrongly that may also come back to bite someone.

[44'cruisingcat]

Originally Posted by Stumble

I have read pretty much all the speculation available at this point, and the very little amount of actual facts. But have tried to stay out of it.

However I have come to a preliminary conclusion that the most likely failure method is just a simple design error in the mast. My internal story is pretty much the following...

The boat was fast reaching under tripple reefed main and jib when it crashed at high speed into the back of the steep short waves found in this area. This placed a huge bending load on the mast at exactly the weakest point of the construction. Specifically the unstayed area at the spreaders. This rapid deceleration combined with high bend loads was beyond the capability of the mast and it snapped.

The major alternate story is that the mast could have been designed for this but there was a failure in the layup. It wouldn't have taken much contamination in the pre-peg to result in a bad section, and it happened at exactly the right spot the mast would have been under design spec. However I find this an unlikely failure mode without some evidence to support it.

The solution of course is that GB will need to replace the masts on the rest of the GB55's and likely do some destruction testing of the mast sections. But I really don't think this dooms the entire line. It is a teething issue (albeit a major one) that can be worked out.

Sounds reasonable to me. But the solution could be lot simpler than replacing all the masts. A set of lower shrouds would fix it.

[44'cruisingcat]

Originally Posted by Sand crab

There was a recent link to a cat with a (rotating?) unstayed mast that was for sale in OZ in one of these forums. It was a large custom build. It was setup and possibly designed with only the main so there were no head sails but then that would be a stayed mast. I can't remember if it was a carbon mast though and can't find it now. It seems like it was on a local FSBO site and not a brokerage but I could be wrong on that. Maybe you guys downunder will know where to look.

Yeah I know, it's actually one of Bob's (Oram) boats. It was on the hardstand at the Boatworks last year when I was there doing some work on another boat.

Talked briefly to the owner, he reeled off some pretty impressive performance numbers, even though a back injury has preventing him from sailing it much.

[SailingMum]

That's sort of right Greg, but actually they haven't avoided all disclosure. GB has made a few posts on SA and the skipper has given his account to them (yet to be published).

I agree that the mast going doesn't condemn the design. But to me it looks like the marketing of it could be condemned. The impression is that it's sufficiently flighty that you either need good expert crew and very careful weather routing, or to use a delivery rig with cut down sails, castrating the supposedly incredible passage times boasted of.

Either way, it's not quite the boat that inexperienced but rich buyers would have expected from the marketing.

I'd like one though! But I think the average family cruising, with the typical risk profile of family cruisers, will likely post faster passage times in an old outremer 55light, which will also be safer in a storm. You can get a decent one of those for about 300k, which for me personally would be in the ballpark of what the GB55 is worth. Still, all that carbon goes well with the Breitling and the pacemaker.

[Delancey]

FWIW nothing disruptive about rotating wing masts, they've been around for prolly thirty years now. As far as single spreader goes, something to be said for KISS most of the time.