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Old 28-07-2019, 11:52   #166
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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Originally Posted by Kenomac View Post
someone will be checking the hydraulic fluid more often.
The report mentioned the lack of a remote level sensor for the hydraulic fluid reservoir tank, but I haven't really seen that kind of sophistication outside of a fancy super yacht. I know Maretron makes such sensors, but the common thinking on smaller boats seems to be that any AP will eventually throw an alarm when the course is not held, plus you should be able to see the nasty red fluid leaking if you actually take a take a look once in a while. (Too many trivial alarms on our old Simrad caused all to be ignored eventually.)

I'm curious to know if anyone has such an alarm?

Also, the report noted that the dual-ram design would completely fail if EITHER ram failed, creating the opposite of redundancy, IMO. Food for thought... not gonna upgrade in that direction.
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Old 28-07-2019, 14:17   #167
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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At the end of the day what happened is a tragedy that could have been avoided if the crew was more knowledgeable, fearful, aware of the power of the boat they were sailing.
Actually quite interested by some references to and some assertions of the crew being incapable or lacking in experience or knowledge. In fact, all five persons on board were according to the report, very experienced and knowledgeable yachtsmen/voyagers. The issue here was that each person seemingly held the view that each other person “knew what they were doing”. However, it is clear now that they did not know what each other was doing.

My principle of crew selection is I prefer to have as little knowledge on board as possible in order that any decision made is expressly mine. Instruction to the crew on watch: “keep your eyes open, watch for other ships, keep an eye on the wind direction and call me if anything needs to be done”. Crew, even if experienced, are not permitted to make unilateral decisions.

Many of my ocean crossings have been uneventfully completed with all crew members on their very first passage. Occasionally an experienced friend will be on board but the instructions above always prevail.

YMMV.
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Old 28-07-2019, 20:28   #168
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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I think in this case the thimble he uses is better than bowline loop to bowline loop, or a snap shackle jaw (for sure). Maybe a sharper turn than a larger radius block pulley, but you wouldn't want a block-pulley to reverse that line anyway. Simpler is better. I do wonder how that fitment is attached to the hull on the caprail. Is it long screwed in, or bolts and backing plates on the underside of the deck.
4 X 5/16" bolts through a 3/8" alloy backing plate under the deck. It's adequate for use as a boom brake and to keep the boom from swinging as the boat rolls.
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Old 28-07-2019, 20:49   #169
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Re: Preventer Rigging -- Lessons from the Platino Disaster

Yes, our autopilot has an off course alarm, that shuts itself off if the correct course is returned to. It also has a rudder alarm, and if the rudder draws too much current, it alarms and quits steering. This can come as a surprise the first time it happens. Now we start for the helm when the rudder angle reaches 19 deg. But, before then, it is time to balance the sails better, if it is ever getting over about 12. Another reef (we have slab reefing), or roll up the headsail some more. They had shortened sail, in anticipation of stronger winds.

It was mentioned above that the one 48 kn gust they recorded was the highest wind strength experienced, and that the average wind strength was in the 30-35 range. At 35 kn, I'd expect the 50 kn. gust occasionally, and for this boat, that's enough to be off the wind with 2 reefs and reduced headsail, and we'd be using the staysail if we were on the wind, and maybe but in the 3rd reef. For autopilots to be happy steering, on should use the minimum sail to keep the boat at speed.

Fwiw, I don't think the helmsman needs to always be behind the helm, although I do agree it is one policy that could work as a safeguard. After the 2nd and 3rd off course alarms, it would have been wise to station someone there. It would also have been a good idea to think, "Hey, I wonder if there's something wrong with the autopilot, and start checking all of it." and maybe, "Why don't we disengage the autopilot and hand steer while we do it?"

.....I just can't get the image of the overboard crew person holding up his hand, and the boat all over the place, and nothing tossed to him. I bet it bothers the survivors, too.

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Old 28-07-2019, 21:35   #170
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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.....I just can't get the image of the overboard crew person holding up his hand, and the boat all over the place, and nothing tossed to him. I bet it bothers the survivors, too.

Ann
Yep, that's the part which bothers me most Ann. You can rationalize all the other stuff one way or another but whilst sympathetic to their situation one cannot help be uncomfortable with the outcome of the MOB situation.

The person in the water was still conscious as indicated by them signalling. A boat that size which departed NZ, with their safety regulations, should have a number of devices to provide a person in the water with bouyancy and light signalling after dark and from the track diagram the boat did not continue directly down wind after the incident but reached backward and forward a number of times..
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Old 28-07-2019, 22:03   #171
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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Actually quite interested by some references to and some assertions of the crew being incapable or lacking in experience or knowledge. In fact, all five persons on board were according to the report, very experienced and knowledgeable yachtsmen/voyagers.
Sorry for not including some of your quote. You are correct.

From the report regarding crew qualifications:

Appendix 1 – Overview of crew qualifications and experience
This section provides a brief overview of the experience held by Platino’s crew members. It is by no means complete and only serves to demonstrate that the yacht was adequately crewed for the intended voyage.

The skipper (co-owner)

The skipper was an experienced seafarer who indicated that her sailing experience spanned 30 years. She estimated she had sailed sixty to seventy thousand nautical miles including an 8 year period spent living aboard a yacht while sailing around the world. The skipper had obtained Boat Master and Coastal Yacht Master certificates and had completed ocean navigation, marine radio and radar operator’s courses. She completed sea survival and marine 1st Aid courses while preparing to sail Platino offshore.

The owner

The owner was an experienced seafarer who stated his sailing experience spanned more than 45 years. His experience included crewing on yachts during races and delivery voyages in the inshore, coastal and offshore arenas. The owner had no formal sailing qualifications but was an experienced marine electrician.

The surviving crewmember

The surviving crewmember was an experienced seafarer who stated he became very involved sailing after an earlier focus on rowing. He owned his own boat and had gained extensive experience sailing as crew on yachts of up to one hundred feet in length. His extensive experience included crewing during races and delivery voyages in the inshore, coastal and offshore arenas. The surviving crewmember had no formal sailing qualifications.

The crewmember fatally injured on deck

The crewmember fatally injured on deck was an experienced seafarer who had been involved with boats and the sea since a young age. He was also an experienced boat builder who served an apprenticeship beginning at the age of sixteen. He was heavily involved in the New Zealand yacht racing circuits on both a local and national level. He built and raced his own yacht and sailed as skipper, watch captain, navigator and crew on many others. He competed in shorthanded and fully crewed races in the inshore, coastal and offshore arenas. He held a Boat Master certificate.

The crewmember lost overboard

The crewmember lost overboard was an experienced seafarer who had been involved with boats and the sea since a young age. He was also an experienced engineer and had owned and operated a small engineering business for 32 years. His boating experience included owning his own boats and being crew for yacht deliveries between various international ports. He sailed regularly for many years on yachts competing in the Auckland Club racing circuit, and numerous times on prestigious yacht races including the Coastal Classic, Sydney to Mooloolaba, Sydney Hobart and the Kenwood Cup. He held a Boat Masters Certificate.
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Old 28-07-2019, 22:50   #172
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Re: Preventer Rigging -- Lessons from the Platino Disaster

I’ve sailed on a boat with a similar crew problem. Everyone is experienced, but many of them might well be deferring to someone they think is more experienced than them. The crew presumably thought the owner was the skipper. The skipper might well have been thinking the guy that had done Sydney/Hobart was more experienced and was reluctant to bark out orders to him.

It’s vital that the chain of command is made clear, particularly when it isn’t obvious.

I believe that we should be thinking more of this than some of the other issues raised. Sure, the autopilot should have been checked, and the preventer should have been properly rigged. But autopilots give up, however well they’re checked, and preventers can let go however they’re rigged.

If you’re sailing downwind in any kind of significant wind and sea state, it isn’t seamanlike not to be ready for the autopilot to throw a fit, gybe, and take the preventer with it. The question is whether you are ready for it, and what you do when it happens.
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Old 29-07-2019, 09:09   #173
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Re: Preventer Rigging -- Lessons from the Platino Disaster

sure, but the preventer rigged as it was is clearly not ok and chain of command does not enter into it.. a competent sailor would make this clear wouldn’t they!
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Old 29-07-2019, 11:53   #174
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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It’s vital that the chain of command is made clear, particularly when it isn’t obvious.

The question is whether you are ready for it, and what you do when it happens.
Yea, you are getting closer to root causes here.

My sense is that, yes, the crew had experience, a couple of them even had some competence (which is different than experience), but there was something stopping/blocking them executing the preparation and then the actual voyage well and seriously, and that “something” was probably in the “leadership” realm.

The various technical issue are consequences, and proximate causes. Even if the autopilot had been 100% there are still many non-trivial probability events which could have still backed the mainsail and broken the preventer (like a wind shift under a cloud band or a kinked isobar, or getting a net around the rudder, or someone accidentally flipping off the autopilot, or a dozen other possibilities). And even if the preventer had been 100%, there are several ways that boom could have ripped the traveler out of the deck and acted as a flail and be extremely hard to control. So, yes, those are all problems which should have been clear to competent people and been seriously addressed (and fixing them would have progressively reduced the risk of the voyage) but they appear to be consequences of an overall lack of seriousness and leadership.

I have gone back and looked at the weather forecasts, and it appears to have been stronger conditions than was called for. This may have been a factor in them being reluctant to go to the effort to reduce sail enough to settle the boat down. But I am puzzled by their lack of realization of the autopilot issue. The report suggests there were enough red flags of several different types, that these folks should have realized. There is a feeling that the crew were just on autopilot also and not alert.

It is not clear to me from the resumes whether anyone on the crew had past significant experience with “the burden and loneliness of command’. That is a distinct skill, which really cannot be polished except OJT
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Old 29-07-2019, 13:51   #175
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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You missed:

Traveller moved to dangerous position without sufficient engineering input.
Traveller stops held by just one (!) M10 bolt of uncertain material and specification and source. Even so it held until the second crash gybe, but a traveller stop properly built for such a large rig could well have lasted a few more gybes, enough time to get the boat back under control. The failure of that bolt was the proximate cause of a bad situation turning into total loss of control and a dismasting.
That's an excellent point.

When the owners purchased the boat, the main sheet block was attached to a FIXED position on the arch that was then removed and replaced by the new traveller, in a different position.

Any decent engineer should have questioned the size of that hardware (including the SINGLE M10 SS stopping block bolt of unknown quality) that was destined one day to see the shock load of a ton and a half of boom whose end was moving at an estimated 20 knots. Gonna need LARGER hardware for those forces.

The newly installed, obviously undersized padeyes on the toe rail beg the same question: Who did the math on this boat's re-fit??
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Old 29-07-2019, 14:04   #176
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Preventer Rigging -- Lessons from the Platino Disaster

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I'm thinking the same thing and wonder why a boom broke can't be rigged pretty much the same as a preventer.


I was gone for three days to a funeral and missed a lot of this, but it doesn’t look like you were answered.
In my admittedly low experience opinion, they aren’t the same at all, a preventer is well, a preventer, it has to be able to absorb any load that can be imparted to it and one reason I feel sure that people say rig them to the end of the boom is to lessen loads on the preventer, but also I’d think even the boom. The loads can be enormous.

A brake I believe differs significantly, the loads a brake will see should be much less than the max a preventer can, because a brake will allow the boom or move, and as the boom moves, the loads should lessen, preventer has it held fast and has to absorb any possible load.

So I don’t think a brake can be rigged to actually be a preventer, it’s not nearly strong enough, it’s not anchored well enough geometry wise, and the boom isn’t strong enough either where the brake is, so I believe a brake once forces get high enough has to allow the boom to move to off load the forces.

Now all this is pure supposition and not from years per experience, I went with a brake largely because the boat had one, that had never been used obviously.
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Old 29-07-2019, 15:57   #177
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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I was gone for three days to a funeral and missed a lot of this, but it doesn’t look like you were answered.
In my admittedly low experience opinion, they aren’t the same at all, a preventer is well, a preventer, it has to be able to absorb any load that can be imparted to it and one reason I feel sure that people say rig them to the end of the boom is to lessen loads on the preventer, but also I’d think even the boom. The loads can be enormous.

A brake I believe differs significantly, the loads a brake will see should be much less than the max a preventer can, because a brake will allow the boom or move, and as the boom moves, the loads should lessen, preventer has it held fast and has to absorb any possible load.

So I don’t think a brake can be rigged to actually be a preventer, it’s not nearly strong enough, it’s not anchored well enough geometry wise, and the boom isn’t strong enough either where the brake is, so I believe a brake once forces get high enough has to allow the boom to move to off load the forces.

Now all this is pure supposition and not from years per experience, I went with a brake largely because the boat had one, that had never been used obviously.
I think of the boom as a 20 foot (~) beam, supported on one end by the gooseneck/pin (strong but not infallible). Then comes where to support the other end of the beam. If supporting at the extreme other end, that divides the bending forces in half, if the sail attached to it where 90 degrees to the wind and square. But the sail is a triangle, so there is more sideways force towards the mast, and if reefed, even more force on the gooseneck side (upwards of 70% of total). In that case, the preventer (or even boom brake) should also be biased forward to get it under the sails side load as well as possible. The benefits are that the beam itself is less stressed along the span (compared to an end and end attachment only). Also, much less preventer line to handle.

On the other hand, with the preventer on the end of the boom (beam), tension loads on it will be less, and if there is a concern about lifting a pad eye or chain plate out, or parting the preventer itself, then end boom attachment would be best. Force has to go somewhere, and in this case the side loads on the goose neck pivot pin will be proportionally higher with the preventer on the boom end.
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Old 29-07-2019, 19:44   #178
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Re: Preventer Rigging -- Lessons from the Platino Disaster

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I think of the boom as a 20 foot (~) beam, supported on one end by the gooseneck/pin (strong but not infallible). Then comes where to support the other end of the beam. If supporting at the extreme other end, that divides the bending forces in half, if the sail attached to it where 90 degrees to the wind and square. But the sail is a triangle, so there is more sideways force towards the mast, and if reefed, even more force on the gooseneck side (upwards of 70% of total). In that case, the preventer (or even boom brake) should also be biased forward to get it under the sails side load as well as possible. The benefits are that the beam itself is less stressed along the span (compared to an end and end attachment only). Also, much less preventer line to handle.

On the other hand, with the preventer on the end of the boom (beam), tension loads on it will be less, and if there is a concern about lifting a pad eye or chain plate out, or parting the preventer itself, then end boom attachment would be best. Force has to go somewhere, and in this case the side loads on the goose neck pivot pin will be proportionally higher with the preventer on the boom end.
You're on the right track but a bit off in some of the detail:

To keep matters from getting to complicated we will assume a loose footed main sail.

When the preventer is fixed to the outer end of the boom and the sail is back winded thereby loading up the preventer line the boom is acting almost purely as a column which is subjected to compressive loading only.

When the preventer is fastened to the boom towards the gooseneck the boom becomes a cantilevered beam with bending moments applied at the preventer fastening.

Most booms are not symmetrical being deeper than broad and consequently weaker for laterally applied bending loads.

One of the reasons a lot of folk don't like to take a preventer from the end of the boom to a forward cleat is rhat if the main becomes back winded and the boom swings anyway because of rope stretch it then goes across the shrouds subjecting them to enormous lateral loads, possibly sufficient to result in a lost rig.
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Old 29-07-2019, 20:29   #179
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Re: Preventer Rigging -- Lessons from the Platino Disaster

If a partially furled, loose footed mail sail was to backwind in 35 knot winds, the force of the sail on the boom would not be exerted on the outermost end of the boom, it would be somewhere near the middle.
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Old 29-07-2019, 21:48   #180
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Re: Preventer Rigging -- Lessons from the Platino Disaster

No affiliation but did personally use one of these during an oops gybe on a large vessel. It slows down the boom speed travel when a bow - boom end preventer is rigged. Simple, inexpensive and works.

https://dreamgreen.org/boom-brake

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