Anti-inversion solutions?

[Greenheart]

The Laser Stratos was mentioned in another thread, and Googling the design, I couldn't help finding its unhappy history - two terrible drowning incidents, associated with crew being trapped by their trapezes, during inversion.

I was wondering if there's a compressed air/inflatable masthead chamber already out there, that can be retro-fitted to any dinghy whose proportions defy easy righting.

It wouldn't require an ungainly permanent masthead 'balloon', and as I think I read on the forum lately, it wouldn't have to use any more compressed air than a 'Soda-Stream'...so presumably it needn't be a costly or weighty bit of kit?

If such a thing isn't available for sale, ready to fit, I'm surprised.

Or...maybe just a large fender, roped through a masthead halyard block, with an end led to port and starboard coamings?

 

[FishyInverness]

Maybe worth investigating the RNLI's hardware that they use for the inshore RIB-type lifeboats, all have self-righting inflatable equipment attached to the A-Frame...

http://www.youtube.com/watch?v=KgLM0z1cjwo

Admittedly not as compact as something for a masthead on a dinghy, but I suspect if you investigate the hardware they use, and find the supplier, the solution may lie there...

 

[Greenheart]

Yep, that's very impressive! Not sure it wouldn't impair upwind performance, after recovery, though...

But if such a system (scaled down to the compact size that would keep a dinghy's masthead afloat) isn't available already, isn't there room in the market for such a thing?

If it saved just one life - or even just obviated an RNLI call-out - it would have been worthwhile.

 

[jwilson]

The Laser Stratos was mentioned in another thread, and Googling the design, I couldn't help finding its unhappy history - two terrible drowning incidents, associated with crew being trapped by their trapezes, during inversion.

I was wondering if there's a compressed air/inflatable masthead chamber already out there, that can be retro-fitted to any dinghy whose proportions defy easy righting.

It wouldn't require an ungainly permanent masthead 'balloon', and as I think I read on the forum lately, it wouldn't have to use any more compressed air than a 'Soda-Stream'...so presumably it needn't be a costly or weighty bit of kit?

If such a thing isn't available for sale, ready to fit, I'm surprised.

Or...maybe just a large fender, roped through a masthead halyard block, with an end led to port and starboard coamings?

I taught dinghy sailing for some years, and at times used fenders at the masthead to stop inversion. I also encountered school dinghies with a mainsail modified so that the top 18" of mainsail had one inch flotation foam sewn in for the same reason.

I don't think there is anything inherently wrong with the Stratos: there have been a few inversion-trapped drownings over the years in a fair number of different boats, ranging from monohull dinghies through cats to a 40 ft cruiser, and the RYA mounted a campaign to encourage crews to carry a safety knife to cut themselves free.

When teaching I had one inversion-trapped incident, and I had to get in the water fast to untangle the trainee. It was not clear from the MAIB report on the Stratos incident how long it took before anyone dived in to help - reading the report it looks as though possibly no-one did - they perhaps tried to recover whilst staying in the safety boat.

Much clearly depends on how confident in the water the person trapped is: when my son was racing seriously in the 49er I tried to get him to wear a safety knife, and he refused, on the grounds that a knife was a) extra weight and b) if on a string something else to tangle. He however was a very fit swimmer/diver, with years of practice in fast dinghies.

 

[Greenheart]

I like the safety-knife idea - vital for so many emergency tasks - but surely its weight need not hinder any adult...and wouldn't it be best worn, strapped above the ankle, not dangling and tangling?

I've only ever seen trapeze wires which were wire - presumably not easily sliced through with a knife. I appreciate that enough of the trapeze harness is made of webbing, to yield to a sharp blade.

Has Dyneema, or some such low-stretch cordage ever been use for trapeze-wires?

 

[Quandary]

The Laser 13 and 15 both had mainsails with closed cell foam flotation built in to the top panel of the mainsail to prevent full inversion, of course these were 'cruising' dinghies and very stable anyway. I was not aware of a substantial problem getting a satisfactory sail shape on my Laser 13 and if it was a compulsory part of the design and allowed for in the rating I have no doubt it would soon be refined by clever sailmakers to make it acceptable to hot racers.
When my kids were just learning to sail dinghies, they managed to invert their Mirror and get the top of the gunter boom stuck on the bottom, prompt action by the club rescue boat got the young one out from under and I was very grateful that they were on hand. The boat was hard to free and we suspected there was some old mooring gear at the bottom.
I tried to make sure the water they sailed in was a bit deeper (or shallower) after that.

 

[prv]

wouldn't it be best worn, strapped above the ankle, not dangling and tangling?

Strapped to the calf is still pretty tangleable. A line which might have slid down your leg and off the end would now get trapped between handle and leg. Not to mention that picking something off one's ankle requires contortions that might not be easy or possible - not sure why it was the norm for divers, but even when I used to dive ten years ago there was a movement to upper arm, chest, etc.

For a dinghy sailor I'd have thought the best place would be the front of the buoyancy aid, well strapped down.

Has Dyneema, or some such low-stretch cordage ever been use for trapeze-wires?

I believe so, yes. For a few months I shared a flat with a pair of top-flight dinghy sailors (didn't sail with them though) and I remember one of them once splicing some dyneema (or similar) in the kitchen. I'm fairly sure he said it was for a new trapeze wire.

Pete

 

[TSB240]

Trapeze Wire

Most boats I have sailed or seen with trapeze wire have an adjustable multi rope purchase attached at the bottom of the wire. This allows the crew to adjust the supporting trapeze length to either suit their height and or their trapezing position fore and aft. It could easily be cut.

In my experience it was very rare to actually stay attached to the wire in a capsize situation. IMHO There is as much risk of being trapped by the various sheets and haliards on any dinghy without a trapeze. A sharp knife should be part of a dinghy sailors personal safety kit.

With reference to the tragic Stratos incident I understood that the relative experience of the helm and crew in comparison to the other regular championship competitors was also considered.

My greatest worry on a wire was about the 17 stone helm who was about to follow me around the mast as our twin wire cat nosedived.

 

[Kelpie]

Auto-inflating masthead buoyancy devices are pretty common, I think Secumar make them in at least two different sizes. Also available are the permanently inflated devices which you slip into the luff groove, they don't seem to affect performance too much.

Some dinghies are more inversion-prone than others. Generally, lots of buoyancy makes the problem worse, especially when it is under the floor, and in the side-decks. So keep all of the buoyancy in the ends of the boat.

The old wooden MkI Wayfarer was the least inversion prone of all the different types. It had a wooden mast and the only buoyancy was at the bow and stern. Newer versions have hollow aluminium masts, and side-deck (and/or underfloor) buoyancy which causes them to float much higher in the water. This also makes it much harder to climb into the centreboard.

 

[trapezeartist]

For anti-inversion, I like the idea of sealed masts but of course that is tied to class regs. Failing that, Crewsaver make a couple of airbags that are quite favoured by schools. I've also seen the foam triangles either side of the head of the sail which are certainly a lot neater than a big bag flopping about. I've tried using a small fender but the weight was counter-productive.

I'd never thought of it before, but the ability to cut a dyneema trapeze "wire" is a handy idea. It also is a slight enhancement to boat performance, unlike the various masthead float ideas.

After all that though, entrapment is a very minor risk and just as likely to occur with all the other string sloshing around in a boat. The first time I had to go under an inverted boat (because the centerboard had fully retracted during the capsize) the thing that alarmed me was all the string floating around my neck and shoulders. I hadn't foreseen that.

I should add that my interest in preventing inversion was not really a safety concern but just because a turtled boat takes a long time to right.

 

[William_H]

Dinghy Inversion

I think before you go for inflatable bags etc you should ensure the mast is water tight so it will have buoyancy. Next is to ensure the CB is locked down at all times. Next is to fit if necessary something that the toes can grip onto under the gunwhale. Many boats have a lip anyway.
When I was teaching dinghy sailing it was standard procedure to get them to invert the dinghy. I got the kids to swim under the hull to enjoy the air space. With both crew "standing" on the under gunwhale ledge they pull the CB to get it up to 90 degrees. Then righted in normal manner.
Of course we did not have trapeze harnesses in training.
However we did have an incident where one kid was trapped under a 10ft Skiff by trapeze harness. He was unconscious when pulled out so it was a near thing. The boat was righted with help from a passing sailor. As an aside that kid never went back to sailing. he went to USA as a gridiron player (now about 1metre across the shoulders) and is now seen on our tele as a sports commentator. I don't think he has forgotten though. olewill

 

[blackbeard]

There is a Stratos variant, the Stratos Keel, which has a 70 kg weight at the bottom of the dagger board. Makes it a lot more stable, obviously; I expect a capsize is still possible, if unlikely. In my view it's quite a nice boat (but, by dinghy standards, a bit heavy of course, and the Stratos is a big heavy boat to begin with). I expect it would be easy to right (assuming you have remembered to make sure board is secured in down position).
Comet Trio has, I understand, a sealed mast which discourages total inversion (although this can still happen I expect). Stable boat which is easy to right.
Dinghy sailing courses don't always give practical experience in righting a total inversion. I could wish they did, but there are obvious practical problems with this.
Some dinghies are very prone to invert and I expect the theory is that they are sailed by expert crew who can right it before it inverts, or at least deal with an inversion. If you have one such, a masthead float makes sense until competent and confident.

 

[Kelpie]

A couple of additional points:

- masthead buoyancy is all well and good until you start to reef, when the leverage goes down- just when you are most at risk of capsizing!

- righting lines can make a huge difference to your ability to right a capsized or inverted boat. I now have permanently rigged righting lines stowed along the gunwales of my Wayfarer. Many people advocate just using a jib sheet instead but in my experience reaching these means leaning into the boat which will just turn a capsize into an inversion. You will also be trying to right the boat with a backed headsail, which is lots of windage in a very unhelpful place. The boat will want to swing downwind and start sailing herself whilst you are still hanging off the side.

 

[Signed Out]

QR Trapeze

Maybe I missed it, but saw no mention of quick-release harness clips, which seem to be the majority now.

My harness has one, although I've not used it yet (still got tags on)- sold dart to buy engine for the bigger bucket before I'd tried it out, and haven't got the contender I dream of yet...

 

[Iain C]

There's some interesting "advice" on here!

You cannot reasonably expect any kind of "seal" to work to make a mast bouyant. By nature it will have all kinds of holes in it for running and standing rigging. I once saw a Fireball mast filled with foam. It was a waterlogged abomination, and ignoring weight in terms of a minimum weight/performance thing, but looking at it purely as heel inducing weight aloft, it also sucked. And did'nt work.

Next, you cannot lock a centreboard down at all times. Any dinghy sailor fresh off an RYA level 1 course will know that it should not even be down at all times, and should be trimmed for the conditions. I've never sailed a boat that allows you to lock it...some daggerboards may have a bungee to overcome the flotation of the board if there is no load on it but that tends to be it.

The modern standard for trapeze wires is 2.5mm-3mm Vectran or similar. Easily cut, and I would think very hard about sailing a boat these days with stainless wires.

Knives...great idea. Many skiff classes will carry them on the gantry (some have class rules as such) and many people will also carry a knife tucked into their BA, or a small hook cutter on thier trap harness. However, to avoid entanglements, it's better to use a non-strappy, non adjustable nappy harness, preferably with a rash vest over the top. Stray string just brushes over you then but you have the knife just in case.

Entrapment...the issue with many modern dinghies is the lack of traditional aft tank, or in skiff classes, the lack of any form of "cockpit". As such, they sit much lower when inverted and there's no air pocket.

QR trapeze hooks...had two, binned them both and just have a standard hook now. One version had a habit of not releasing under test unless you were leaning one way, another version I have come across fired with such force that you were in danger of taking someone's eye out! My crew "fired" it once, and then could not get it back together (experienced skiff sailor too) so we had to get home in a F5 with him hanging off the trapeze handle.

Masthead flotation, in my mind, is actually not a good idea at all. Ignoring any performance issues/windage, it sits there like a pair of stabilisers on a child's bike. I can sort of see the entrapment reduction benefits, however it pains me deeply to see students on a "performance sailing" course with masthead flotation. That's an oxymoron in my eyes. More to the point, the thing that everyone conveniently forgets, is that a turtled boat sits there, going nowhere. You can sit on it and watch the world go by with your rig pointing straight down. A boat held forcebaly on it's side in a blow will often drift downwind faster than you can swim. That is incredibly dangerous in itself...not forgetting that it's drifting with 20 odd foot of jousting pole! Add to the fact that if the wind gets under the rig after a windward capsize the whole lot can easily just be flipped 180 degrees at a huge speed just underlines the fact that masthead flotation is the devil's work!!

It may surprise people that when I was racing 18 foot skiffs, no-one wore bouyancy aids. The thought of getting pinned against the rig or racks by 50N of flotation in the event of a big crash was not a pleasant one in a boat like that. Far better to be able to dive down away from danger if it required. And that's not bravado...the Aussies came up with that one, the same guys who imposed the knife rule, and the same guys who tend to wear ridiculous suncream and sometimes ladies tights over thier sailing gear so they don't get stung by jellyfish!

I hate to say it but when it comes to masthead flotation there's usually a very good reason why it's very rarely seen!

 

[Kelpie]

Interesting post, Iain, thanks.
To present an alternative viewpoint, in Wayfarer circles masthead buoyancy is generally accepted as a sensible safety precaution, and inversions are to be avoided if at all possible. This is perhaps due to the size of the boat, and that righting from inverted can be really difficult. It is said that a good, fit, crew will only have one or two attempts at righting from inversion before they run out of energy.

I accept that smaller, lighter, and less beamy boats will have different requirements.

 

[blackbeard]

There's some interesting "advice" on here!

.......
Next, you cannot lock a centreboard down at all times. Any dinghy sailor fresh off an RYA level 1 course will know that it should not even be down at all times, and should be trimmed for the conditions. I've never sailed a boat that allows you to lock it...some daggerboards may have a bungee to overcome the flotation of the board if there is no load on it but that tends to be it.

.......

I assume you haven't sailed the Stratos Keel, there is a strap fitted specifically to keep board down all the time when sailing.
Possibly you might, if you wish, regard it as a keelboat rather than a dinghy, although it's retrieved and launched with a trolley dinghy-style.

 

[Seajet]

When I had a Contender I found it had a nasty habit of inverting and staying like it ( sometimes because the masthead was in the mud ) a pig to get back up - I have sailed all sorts of fast dinghies since 1970 and am about 12 stone.

I filled the mast with closed cell foam, then tried a capsize test; I wouldn't say it completely cured the problem, but it helped a lot.

Re. earlier negative comments on foam in masts, there was no waterlogging or any noticeable weight penalty; I suspect that Fireball chap had used the wrong foam !

I do think foam heads on mainsails should be wider used, no performance snag if it's in the class rules.

 

[Iain C]

Blackbeard-the Stratos keel is as much a dinghy as a Flying Fifteen or a Jaguar 21. Anything that has 120kgs of lead locked in position is most certainly NOT a dinghy!!

Seajet...a Contender is a pig to get upright. Mine would almost immeadiately go mast upwind and then the only solution was the "eskimo roll" (going under the boat hanging onto the board) and then popping up on the correct side ready for a swift recovery.

 

[jwilson]

There's some interesting "advice" on here!
It may surprise people that when I was racing 18 foot skiffs, no-one wore bouyancy aids. The thought of getting pinned against the rig or racks by 50N of flotation in the event of a big crash was not a pleasant one in a boat like that. Far better to be able to dive down away from danger if it required. And that's not bravado...the Aussies came up with that one, the same guys who imposed the knife rule, and the same guys who tend to wear ridiculous suncream and sometimes ladies tights over thier sailing gear so they don't get stung by jellyfish!

I hate to say it but when it comes to masthead flotation there's usually a very good reason why it's very rarely seen!

A lot of what you say I agree with entirely. In a sailing school context there is however a place for masthead buoyancy, especially in hard to right dinghies. I always made sure every student experienced a turtle though. Sometimes you got those who were just not big/fit/strong enough to right from 180 on their own. Needn't stop them sailing, but they had to be aware that they ALWAYS needed safety cover.