Safety Warning... Securing of retractable keels/weighted centreboards.

Andy Dingle · 27 Jun 2019, 22:23

This was sent to our club from the Marine Accident Investigation Branch after the tragic loss of a fellow sailor and I thought it relevant to Swallow Yachts owners.

https://www.gov.uk/maib-reports/safety-warning-about-the-securing-of-retractable-keels-or-retractable-weighted-centreboards

Regards

Andy - Etap 34s 'Swallow'

Sea Simon · 02 Jul 2019, 10:01

Very sad.
Interesting and thought provoking stuff; worth a read. Not "new news" (in the technical discovery sense)?
And a rather different setup to ours? This boat relying on the weight of the keel bulb, rather than water ballast and some "form stability" for righting.

It was not clear to me from the safety bulletin if the disabled victim was strapped in to the boat, or if they were trapped under the boat by buoyancy aid/Life jacket? Guess this would probably not be a message that the establishment want to broadcast? I know several people who don't wear 150N automatic LJs for this sort of reason.
There is a little more info if you follow the link on the .gov page, thru to the actual MAIB safety bulletin. This indicates that the info issued so far is only preliminary.

My understanding is that my BRE has the (slightly) weighted board, only so as to sink it?
A retracted board might hinder any righting/recovery by the crew, or outside assistance?

I had last year looked at my board " down haul", and pondered maybe fitting some sort of cleat or similar? However, I have done nothing. Mainly because I am often sailing in a river, or close to rocks, and so want the board/boat to self-protect on impact.

Has anyone here already done this sort of mod?

Michael Rogers · 02 Jul 2019, 14:09

Not that it directly affects you big boat boys, but it's not only weighted centreboards which mustn't retract with potentially dire consequences if they do. Those of you forum-ing in 2014 will recall my 'no wrecks and nobody drownded' experience off Durdle Door (see Gen Discussion in July 2014) when my absolutely non-weighted dagger board retracted after the boat turtled - 45 minutes in the water and a visit to Dorset General A and E for multiple cups of hot tea....

It absolutely can't happen again after an effective mod (as far as I know - I DON"T intend to put it to the test), one of a string I made after that adventure, now makes it impossible for the DB to fall into the boat in that way.

Michael Rogers PS was it really 5 years ago??!!

Martijn · 02 Jul 2019, 15:44

Usually weighted centerboards provide just a very small part of a boat's stability at best. The weight is just meant to keep the plate down, although it lowers the overall center of gravity as well thus improving stability slightly. The simple fact that the centerboard retracts seems to suggest the heeling angle is beyond 90-95 degrees at which point the righting lever for most small boats is (almost) non existing and she's about to turn over.
The boat in question is very wide and has very little freeboard making it near impossible to get back up again. It should have plenty of initial stability but once capsized the situation would have become dramatic quickly. In fact judging from the hull shape I would be surprised if the range of positive stability exceeds 80 degrees.

@Michael Rogers:
Can you tell us what happened in your case, and what you did to prevent this from happening again?

Michael Rogers · 02 Jul 2019, 18:37

Hallo Martijn

It's all there on the forum in 2014. I wrote about it at some length, partly because I'm a bit of a dramatist I suppose, but also because I learned a lot from the experience and thought I'd pass it on (one of the useful things about a forum I suppose).

My Trouper is 12 ft and very stable, but I managed to capsize her! I was on my own in a F4-5 (one reef down). Before I could right her she turtled. Initially the dagger board was sticking up helpfully, but as I reached for it, it slid down into the hull. Even if I'd dived under the boat (I'm not a super swimmer) and got it up (it would have been up) into the DB case, there was nothing to keep it there.

The most interesting part of it all was that I was about 200 yards from the shore. I waved, people waved back!! It was 45 minutes before it occurred to someone to dial 999. I got mild hypothermia, but no damage to me or the boat (recovered by RNLI).

My modification was simple - a series of deep notches in the after side of the (wooden) DB, and a stout taut shock cord loop round the after end of the DB case, with an extra loose loop to make it easy to adjust it. It's also made adjustments during sailing much better. I'm sure the DB couldn't slide back into the upturned boat now.

Peter Taylor · 05 Jul 2019, 13:37

Quote from: Sea Simon on 02 Jul 2019, 10:01
I had last year looked at my board " down haul", and pondered maybe fitting some sort of cleat or similar? However, I have done nothing. Mainly because I am often sailing in a river, or close to rocks, and so want the board/boat to self-protect on impact.

The centreboard downhaul on Seatern has a Clamcleat of the sort that releases if there is a sharp tug on it (CL257). This was fitted as standard by SY when Seatern was built. I'm ashamed to say that I have indeed tested it by sailing into too shallow water and it does work!

Peter

Graham W · 05 Jul 2019, 14:37

I think the CL257 is standard on BR's too.

The black plastic release catch can be removed by unscrewing it. Make sure that you reassemble the catch the right way up. I didn't, rode over an anchor chain and shredded my downhaul string in spectacular fashion.

Sea Simon · 07 Jul 2019, 08:27

Thanks for that.

My BRe has a cl257 cleat on the rudder (which has been proven to be very effective) but nothing on the centre board down haul.
I might try the breakaway cleat on the board. Any suggestions on securing the cleat to the trunking?

Talking of cam cleat products...I carry a couple of power grip cleat 261, and very usefu they are too.
Having looked at my issue during the week, I see I could use one of these as a line lock on my board downhaul.
However, the breakaway has obvious, significant advantages. Especially for only £12 or so.

Peter T · 09 Jul 2019, 21:31

I was wondering if the CL257 could support the weight of the centreboard sticking out from an upturned BRE hull without popping the release disk thing so I asked Matt at Swallow yesterday when I was talking to him about something else. Matt thought it probably would, so it sounds like quite a good idea, which I guess is why Peter Taylor has one on Seatern (presumably a similar sized centreboard).

We also discussed the possibility of the line falling out of the cleat in the event of an inversion but thought it might not because it would by then be under tension. Having thought about it since, I suppose you would in practice have it under tension all the time, working against the force of the cleated down-haul.

What I didn't do is ask Matt where might be the best place to mount the cleat (sorry Simon)!

Graham W · 11 Jul 2019, 08:18

Here's an account of a full turtle in my BR20 in which the centreboard stayed upright for a while, held up by the downhaul and CL257, but eventually let go under significant provocation https://www.swallowyachtsassociation.org/smf/index.php/topic,1170.msg8287.html#msg8287

On BR20's, the CL257 is mounted on the aft top end of the centreboard case, within reach of the helmsman.

Peter Taylor · 29 Jul 2019, 05:24

Quote from: Peter T on 09 Jul 2019, 21:31
I was wondering if the CL257 could support the weight of the centreboard sticking out from an upturned BRE hull

It's worth noting that the load at which the CL257 gives way is adjustable, it is set by rotating a small cam. However, how you calibrate the setting I've no idea! Alternately capsizing and running aground until you get the best compromise, I suppose!

Peter