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Chris A

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Mar 29, 2014, 11:34:52 AM3/29/14
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A repeat of 1979, boats sinking at Putney. It was always going to be rough and I hope those boating had risk assessed their boats for the conditions.

Carl

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Mar 29, 2014, 1:58:38 PM3/29/14
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On 29/03/2014 15:34, Chris A wrote:
> A repeat of 1979, boats sinking at Putney. It was always going to be rough and I hope those boating had risk assessed their boats for the conditions.
>

Had the ARA, & later BR, Council & Executive worked through the 2000s
_with_ those advocating full shell buoyancy instead of opposing &
viciously smearing & defaming them, & had they worked with us to
establish a data-base of shell makes & what it needed to make them fully
buoyant, then fiascos like today's, & 2007's, HoRR would never have
happened.

Had BR not ducked its responsibility as an NGB by leaving it to clubs,
totally without guidance, to assess the flotation capabilities of their
fleets, then again this would not have happened.

You, Chris, were a member of Council throughout that period. Yet IIRC
you raised not a peep against the crude & thuggish official chicanery
then going on. In fact, only 1 Council member had the guts to stand &
eplain to the meeting exactly why he opposed what was going on. As he
did so, the rest of you sat on your hands like embarrassed schoolboys &
did precisely nothing. So maybe less of that self-righteous 'hope those
boating had risk assessed their boats for the conditions' stuff would be
in order?

Right now, as I'm not there myself, I'm praying that no one was hurt in
this resulting mess?

In this way rowing has made yet another very public display of its total
lack of hydrostatic savvy. These sinkings need not have happened. But
they will happen again & again until our sport wakes up & learns that
well-designed & well-retrofitted eights would neither have sunk, nor
have become so swamped as to be unrowable.

meanwhile, typifying the brain vacuum at the top, the best safety advice
that BR's Water Safety Committee was able provide in the week before
this latest fiasco was: "Remember to close your gate"! Sorry, mate, but
the stable's empty & your horse has bolted.

Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: tinyurl.com/2tqujf
Email: ca...@carldouglasrowing.com Tel: +44(0)1932-570946 Fax: -563682
URLs: carldouglasrowing.com & now on Facebook @ CarlDouglasRacingShells

simon.da...@virgin.net

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Mar 29, 2014, 4:04:29 PM3/29/14
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On Saturday, March 29, 2014 3:34:52 PM UTC, Chris A wrote:
> A repeat of 1979, boats sinking at Putney. It was always going to be rough and I hope those boating had risk assessed their boats for the conditions.

I sincerely hope that there have been no injuries or worse! I presume there was a strong Easterly blowing??

However This just about starts to explain some of the problems that Rowing in GB faces, or more to the point, what rowing in GB has not faced up to!!

For a FISA umpire to say the above raises the question immediately as to why the event went ahead in the first place. I think everyone knows the answer to that one and unfortunately until we have, god forbid, a fatality, events will continue to be run in such circumstances.

Chris, I hope the comment about crews risk assessing their boats for the conditions was tongue in cheek because both you and I know the majority of crews will have just put their boats on the water with maybe some crews adding some 'gaffer' tape between the riggers just in case!

It will be interesting to comment further when full details are known.

Simon D




stew...@gmail.com

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Mar 29, 2014, 6:04:54 PM3/29/14
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I was on the water with a College crew when the race was abandoned, and the marshalling post-abandonment was a total fiasco. More thoughts tomorrow when I've processed the rest of the London Pride in my system.

Stewie

Chris A

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Mar 29, 2014, 7:30:37 PM3/29/14
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Simon it's not. We need boats which float - some pictures doing the rounds this afternoon show boats that don't. AND we still need people to consider whether they're up to the conditions. I wouldn't have coxed a boat with no underseat buoyancy in conditions likely to be prevailing today. In 2004 we were in a wooden Empacher with no underseat buoyancy. I had already told the crew that we wouldn't be taking part before the race was called off.

cdracin...@gmail.com

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Mar 30, 2014, 7:07:07 AM3/30/14
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It's not precisely what, pray?

We're beset by pettifogging regulations, descending thru multiple sub-levels with various ways to prevent participation, yet BR still won't legislate to end the use of shells which are so plainly unfit for purpose that they become unsafe & unrowable when you get a bit of wind against tide.

Every effort I & others have made over many years to get BR to cooperate on flotation standards has been insolently ignored by the same officers who in each case strove to nail blame for causing their own deaths onto the last 2 rowers drowned by defective equipment & defective safety advice. What is it about the sort of people who so much want to be "in charge" of things they don't understand, & why do their egos & self-importance matter so much more to them than doing the right & proper thing?

Who in British Rowing will now have the wit & integrity to buckle down & engage with those of us who do understand the science of flotation & have been awaiting their invitation to work to sort this out. It won't hurt in the least, chaps, so why not give it a try?

Carl
(from his phone)

rowin...@hotmail.com

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Mar 30, 2014, 4:08:58 PM3/30/14
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On Saturday, 29 March 2014 15:34:52 UTC, Chris A wrote:
> A repeat of 1979, boats sinking at Putney. It was always going to be rough and I hope those boating had risk assessed their boats for the conditions.

http://www.youtube.com/watch?v=Y3WJw33dhAE I'm sure one would expect all of these boats to be bouyant.

Henry Law

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Mar 30, 2014, 6:52:11 PM3/30/14
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I've seen that before, but not really watched it with attention. It's
terrifying.

* Crews swimming to the bank (despite someone intoning "stay with the
boat" over the PA);

* boats being made to capsize (the black boat at about 0:36, presumably
as the result of those idiots standing up in it);

* a rescue launch nearly having a collision with a racing crew, still
unbelievably being allowed to continue, and which comes close to ramming
the black boat

... and as far as one can see the only "rescue launches" to be seen are
tin fish with space for one-third the complement of a single eight. Who
was in control and why was this carnage allowed to continue for as long
as it was?

In reponse, Ric, to your direct point, I think I can see a difference
between the boats. The yellow (Vespoli?) eight is rowable, and so is
the second black boat, the one that appears at about 1:40 or so.
Whereas the first black boat seemed to just go under. (But that may
just have been the result of the crew's mad standing-up capers).

--

Henry Law Manchester, England

Carl

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Mar 31, 2014, 6:50:14 AM3/31/14
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For a spot of "deja vu all over again", let's return to 2007:
http://londonist.com/2007/04/horr_sink_or_sw.php

According to Einstein, insanity is "doing the same thing over & over
again & expecting different results".

It's worth studying this short PDF:
http://tinyurl.com/mrrj58g
(Why does Google make the original URL inaccessible, I wonder. Nothing
to do with wanting to control everything, of course)

In that document is a telling headline:
"The primary motivator of decisions to invest in protection is the size
of experienced losses — not losses that are avoided. The more effective
an investment is in preventing harm, the more difficult it is for
decision makers to remember the need for the investments"

Have we, or will we get, any figures for:
1. how many boats (& of which makes) a)sank, b)were swamped & retained
their seated crews?
2. how many boats lacking under-seat compartments took part?
3. how much damage was done?
4. how many crews had to be rescued?

And have we any reactions from the PLA & RNLI?

coach

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Mar 31, 2014, 7:46:53 AM3/31/14
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On Saturday, 29 March 2014 15:34:52 UTC, Chris A wrote:
> A repeat of 1979, boats sinking at Putney. It was always going to be rough and I hope those boating had risk assessed their boats for the conditions.

I was on the water in a launch and provided reports to the race management on the conditions around the Fulham Bend.

There is no doubt that they were rough and unpleasant. But, in my sector of view, they were not impossible for a properly buoyant boat with the technical skills to handle rough water.

I understand that the closer to the finish and beyond, conditions were somewhat worse and, whilst remaining buoyant, many of the leading crews were taking much longer turn beyond Putney Rail Bridge. This was leading to a backlog of crews. It then takes only one or two boats, that are not as buoyant as they should be, t get into trouble, and the problems begin to escalate.

Most of the leading crews raced from Hammersmith to Barn Elms in the "In-shore" zone. This was not going to be an option once crews wanted to return up-stream.

Yes, in ideal world, Control Commission could check each boat for its buoyancy before boating. In real world with 400 crews boating from a dozen locations, this is not going to be possible. We simply do not have enough officials/volunteers over and above those on the water to undertake this role. Even if we could find these extra bodies, how are they supposed to check that the boat has the correct buoyancy for the weight of the crew.

Phil

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Mar 31, 2014, 8:18:10 AM3/31/14
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Does not every boat already have a serial number (e.g./ CBR001)?
Phil.

Carl

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Mar 31, 2014, 9:30:16 AM3/31/14
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I agree that it shouldn't, indeed it can't, be for event organisers to
check shells for flotation.

That's why we used to offer a shell flotation certification service:
1. Measure & weigh the 3-D hull form, shell thickness, fittings & its
existing sealed compartments.
2. Compute its crewed flotation characteristics when swamped.
3. Define the required additional flotation required to meet the FISA
Flotation Standard, crewed & floating with level trim.
4. Where required, install or extend closed buoyancy chambers.
5. Certify the shell for the safe crew weight.

But, with Hammersmith opposed to & obstructing any rational shell
flotation policy, we had to discontinue the service. Yet another
opportunity for safety cooperation spurned.

Yes, there could be a certification process which would ensure that
Saturday's fiasco could not happen again, with only properly certified
shells being permitted to race. And I am concerned that too many shells
presently claimed to meet the FISA standard actually do not do so.

All would take is BR's cooperation.

rowin...@hotmail.com

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Mar 31, 2014, 9:36:57 AM3/31/14
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Carl, would that mean weighing every crew to make sure they weren't in too small a boat?

Carl

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Mar 31, 2014, 10:45:59 AM3/31/14
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On 31/03/2014 14:36, rowin...@hotmail.com wrote:
> Carl, would that mean weighing every crew to make sure they weren't in too small a boat?
>

I think not. There has to be a sense of proportion here & it's rather
like insurance - the policy defines the terms under which it will
provide cover & if you go beyond those terms it may not cover you.

A flotation certificate guarantees that, with that crew weight properly
distributed, no seat in the swamped boat would go more than 5cm below
the water (that's the FISA standard).

The FISA standard (a slightly more permissive version of the flotation
standard which I had developed some 10 years ago) has 2 specific objectives:
1. Keep the crew torsos out of cold water
2. Ensure the boat remains rowable when swamped.

What is not so well appreciated is that the crew's legs & body make
modest but useful contributions to flotation. By displacing water,in
addition to that displaced by the hull & its enclosed compartments, they
increase that displacement as the boat sits lower, conferring a safety
margin over & above the flotation provided by the boat.

Cheers -

rowin...@hotmail.com

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Mar 31, 2014, 11:39:49 AM3/31/14
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Hmmm, so certification wouldn't actually ensure that 'Saturday's fiasco couldn't happen again' because it relies on all 420 crews not being under boated and having their crew weights distributed as certified. Sadly most clubs don't have the luxury of being able to provide boats that necessarily fit these criteria for every race/ crew/ squad season.


Peter Ford

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Mar 31, 2014, 1:36:59 PM3/31/14
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> of experienced losses -- not losses that are avoided. The more effective
>
> an investment is in preventing harm, the more difficult it is for
>
> decision makers to remember the need for the investments"
>
>
>
> Have we, or will we get, any figures for:
>
> 1. how many boats (& of which makes) a)sank, b)were swamped & retained
>
> their seated crews?
>
> 2. how many boats lacking under-seat compartments took part?
>
> 3. how much damage was done?
>
> 4. how many crews had to be rescued?
>
>
>
> And have we any reactions from the PLA & RNLI?
>
>
>
> Carl
>
>

None of this should be taken as particularly accurate (we were sitting above Barnes Bridge in relative calm waiting to be told what to do while all this was going on), but from chatting to people in Putney afterwards:

1) I think the first crew to swamp was crew 42, Karlsruhe Wiking from Germany; however, I would imagine they were borrowing a local shell, so that their overseas status was potentially only relevant if their cox was unused to the river. We spoke to one of their rowers (who seemed fine once he'd had a shower), and I believe they swamped somewhere near the Black Buoy, continued moving slowly down the line of moored boats, and got back ashore under their own steam.

2) I believe possibly one more boat swamped while still racing?

3) I believe a UL crew managed to end up broadsided on the Black Buoy, but were fortunate enough that the wind helped them get clear of it before their shell had been snapped in the tide.

As others have said, even by the time we (crew 228) eventually were allowed to paddle back down to Putney (by which time, on the racing line at rate 20, we only took on perhaps an inch of water in the footwells), the difficulty was controlling the flow of boats into the spinning zone. The marshals were attempting, with little success, to get crews to stay back and keep boats from piling up in an out of control queue along the line of boats at Putney, and the ensuing mass of boats by Putney Pier made the spinning less efficient and the queue even worse.

As for the marshal up on the Chiswick stretch who was telling crew 280-something to "move to Surrey", his assumptions about the levels of local knowledge amongst club lower boats were quite remarkable...

Peter

Richard du P

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Mar 31, 2014, 1:50:16 PM3/31/14
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On Monday, March 31, 2014 12:46:53 PM UTC+1, coach wrote: [in part]

> Most of the leading crews raced from Hammersmith to Barn Elms in the "In-shore" zone. This was not going to be an option once crews wanted to return up-stream.
>

Richard, can I be sure that I understand you?
Leading crews were racing well to starboard of where one would expect them to be?
- in the water that returning crews would later be using?
- possibly inside a red buoy or two?
- which race officials were unable or unwilling to prevent?
- and which would have made conditions seriously unfair for later-starting crews, who would have been obstructed in such a manoeuvre by returning crews???

Regardless of the arguments above about buoyancy and certification - which I wish the sport had taken on board long ago - surely, as soon as a few competent masters of vessels do something which later competitors would be unable to do

..... there's a strongish case to suspend racing, for unfairness?

Or have I misunderstood?

Richard du P

Carl

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Mar 31, 2014, 1:58:11 PM3/31/14
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On 31/03/2014 16:39, rowin...@hotmail.com wrote:
> Hmmm, so certification wouldn't actually ensure that 'Saturday's fiasco couldn't happen again' because it relies on all 420 crews not being under boated and having their crew weights distributed as certified. Sadly most clubs don't have the luxury of being able to provide boats that necessarily fit these criteria for every race/ crew/ squad season.
>
>

Actually, no.

First of all, it is normal engineering to build a safety margin into any
provision, just as your shell should be stronger than the biggest
service load it's likely to encounter.

And then: If you do choose to overload your boat, I've already
explained that the slight increase in depth of immersion results in a
bit more of the crew's bodies going below the waterline, thus enhancing
the computed flotation capacity.

If a vessel descends to the point where it has no further above-water
reserve volume, then it sinks. That's never going to happen with a
crewed & adequately buoyant rowing shell since part of the bodies (below
the 5cm above the seat level specified in the standard will be already
immersed & any increase in depth of immersion continues to increase the
displacement by immersing more of each crew member, more of the boat, etc.

One reasons why many shells filled rapidly on Saturday was that most
wing-rigged boats have cut-down saxboards. The pictures taken that day
from Hammersmith Bridge show waves running along the sides of the hulls
with crests at, or over, the sax tops. It is these waves brimming over
the edge, not the showy but really rather insignificant spray flying off
oars & riggers, which cause rapid swamping. And lowered saxboards
greatly increase this problem.

Any wave field has a wave height spectrum (there are no "rogue waves",
just fewer, bigger ones at that edge of the spectrum). Water flow over a
lip is easily calculated & depends strongly on the height of the wave
above the lip. Until the first few big waves reach the sax top, almost
nothing comes in. Then a quite small increase in average wave height
starts a sudden influx - as the waves rise the flow per unit length of
wave escalates & the length of sax over-topped by waves increases, so
with just a small increase in wave height the water just gushes in.
That's how an eight can go, in just a few strokes, from seeming secure
to taking on a tonne of water within 10 strokes.

One bonus from full shell buoyancy is it greatly reduces surging of
water inside the boat. This helps in 2 ways: first, it greatly reduces
energy dissipation by friction & impact of sloshing water; second, it
stops masses of water from flowing to one end. Thus it makes a more
effective (& stiffer) racing shell while reducing the tendency to get
bow or stern heavy. Remember how small differences in wave heights
above the sax hugely increase influx? Every lump of water you take on
lowers the boat in the water & rapidly increases how fast you fill up -
it's a 1-way trip, especially if 1 end goes down first.

This isn't a simple concept, but any club wanting to do well in racing,
be safe in training & finish high in the HoRR & other stormy heads is at
best ill-advised to use under-buoyant shells. And - wing-rigged shells
will always take on water faster than boats with higher saxes.

robin_d...@hotmail.com

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Mar 31, 2014, 4:51:37 PM3/31/14
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After all the debate 7 years ago about the introduction of the buoyancy retrofit rules in Scotland, we as a small club on a Tideway-like river instigated a 2 month-long retrofit programme that resulted in all of our admittedly (mostly 1978-1982-built) Carbocraft fleet being enclosed. 4 of our VIIIs thus modified are essentially similar to the boat that sank in the 1978 Boat Race with additional sealed bulkheads and hatches under the seats.

Sadly, lack of willing volunteers and cooperative weather at the appropriate time of year in the past seasons have precluded swamped rowing tests on video on the Tay. This year in the aftermath of the Tideway shenanigans would probably be as good a time as any to try to perform this test to update the Blockley campaign website information pages. As we have otherwise identical boats rated at 65, 75, 85 and 95kg it would be possible to compare the effect of 'underboating' the same crew with a 30mm difference in enclosed deck volume, for instance.

Just need to try to persuade the students to participate - wish me luck!

As a technical question - as regards the problem with overflow, why could the saxboards not feature cut-outs (with bolt-in pieces to plug unoccupied space) where the wing riggers are bolted onto the boat and retain at least the thickness of the rigger frame in additional height? I know there would be some issues to do with clearance of the oar handle end, but if the sax is flared laterally (ie similar to recent Pococks) this could be avoided.

mruscoe

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Mar 31, 2014, 5:09:52 PM3/31/14
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Here's a video that I saw linked to on Facebook.

https://www.youtube.com/watch?v=sVHQeXRb7iE&feature=youtube_gdata_player

Nereus go inside the of one of the red buoys at 15:14. I don't know
whether they bailed any water out before picking the boat up near the
end, but if they didn't they wouldn't be the only (Empacher-equipped)
crew that I know of who got through it without picking up a lot of water.

Chris A

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Mar 31, 2014, 6:54:03 PM3/31/14
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That looks very rough but not unrowable.

Carl

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Mar 31, 2014, 7:32:00 PM3/31/14
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What I don't understand, Robin, is the reluctance of students to do
practical experiments. Should they even be students if they lack that
enquiring zeal? It's almost as if they fear either over-exertion,
getting feet wet, or that something might come up from the Tay to bite
them. Perhaps the reality is that they fear looking silly? But real
adventures (even rather mild ones like this) can be fun. Tsk!

Yes, of course wings could poke out through holes in the saxboard - just
supposing the makers gave the influence of water uptake on boat speed
any thought. And it'd make for a stiffer, as well as a drier, boat by
deepening the hull section. And there are other ways of keeping water out.

rowin...@hotmail.com

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Apr 1, 2014, 1:28:03 AM4/1/14
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The stretch of tidal river that Robin rows on makes the Tideway look hospitable! I wouldn't willingly sink their either ;)

Richard du P

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Apr 1, 2014, 3:39:14 AM4/1/14
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On Tuesday, April 1, 2014 6:28:03 AM UTC+1, rowin...@hotmail.com wrote:
> The stretch of tidal river that Robin rows on makes the Tideway look hospitable! I wouldn't willingly sink their either ;)

My friend William McGonagall tells me it's Silv'ry; maybe that's not good?

Carl

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Apr 1, 2014, 5:30:30 AM4/1/14
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Alas! I am very sorry to say that William McGonagall has been taken away.

Re Ric's cautious comment:
I don't advocate testing flotation in mid-river on a windy day. But
Robin has shown us some idyllic Tayside spots where, in shallow water, a
flotation test would be so easily conducted with all necessary
safeguards present.

Rather better than discovering your shell's inadequate buoyancy by
sinking it on the Tideway on a breezy day in a Head race with eights
going every which way?

If we fear the inhospitable waters on which we row, all the more reason
to first check that our equipment does its job.

coach

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Apr 1, 2014, 7:30:25 AM4/1/14
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Yes, they came down the inshore zone.

Yes, they would have clashed with returning crews, had there been any.

Yes, Fairness would have been an issue.

Richard du P

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Apr 1, 2014, 10:42:39 AM4/1/14
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On Tuesday, April 1, 2014 12:30:25 PM UTC+1, coach wrote:
>
> Yes, they came down the inshore zone.
> Yes, they would have clashed with returning crews, had there been any.
> Yes, Fairness would have been an issue.

Thanks for the confirmation; seems more believable now I've seen the video of Nereus, with its nice close view of the Black Buoy.

You'll understand that I raised my rather fastidious question about fairness BEFORE I enjoyed the experience of reading the Vets sorry Masters Head results ..... which take the sport to a surreal new level.

I wonder, should the Vet Head get away for ever more, from the last Sunday morning in March, and the change of the UK clocks? Not the first time those pesky clocks have made trouble for mature rowers.

Richard du P

robin_d...@hotmail.com

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Apr 1, 2014, 10:46:16 AM4/1/14
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>
1) Alas! I am very sorry to say that William McGonagall has been taken away.
>
2) Re Ric's cautious comment:
>
3) I don't advocate testing flotation in mid-river on a windy day. ..(But
> Robin has shown us some idyllic Tayside spots where, in shallow water,) a
> flotation test would be so easily conducted with all necessary
> safeguards present.
>
4) Rather better than discovering your shell's inadequate buoyancy by
> sinking it on the Tideway on a breezy day in a Head race with eights
> going every which way?
>
Carl,

If you have deliberately written that in the style of a 4-line McGonagall (rhyming the last word of the middle two lines and those of the first and last despite a slightly tenuous meter in the middle), firstly, - my hearty if somewhat terrified congratulations.

Secondly - Please, please, for God's sake can someone in the vicinity of Chertsey please go and throw a plate of peas at the CDRS premises to put him off 'ere he starts doing this on a regular basis?

robin_d...@hotmail.com

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Apr 1, 2014, 11:02:47 AM4/1/14
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Incidentally - on a point of order : could I suggest changing the last line to :

"If in these inhospitable waters we do not wish to bob, all the more reason
to first check that our equipment does its job. "

Somewhat more pertinently - McGonagall has already considered the health and safety aspects of life in the following jolly ode brought to us by Messrs. Claims & Direct Esq.

"Accidents will happen by land and by sea,
therefore to save ourselves from accidents, we needn't try to flee,
for whatsoever God ordained will come to pass
for instance, ye may be killed by a stone or a piece of glass"

Sorry for the off-topic ramblings - I genuinely take the buoyancy issue very seriously.

robin_d...@hotmail.com

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Apr 2, 2014, 2:18:47 PM4/2/14
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Being sensible again for a minute - Vespoli have just posted this advert which at least indicates that they are aware of what is going on on our side of the pond and should be commended. Whether this has any effect west of the Atlantic will be interesting to see.

"Is Your Boat Safe?

Rowing is a "flat" water sport that rarely takes place on placid waters. Dangerous situations can lead to serious and sadly, fatal accidents. Rowing is a sport for all and we at Vespoli believe every rower should be safe on the water. Safety starts with the boat you row. Vespoli USA is the first, and only, US boat builder to voluntarily adopt the FISA Flotation Standards. These standards are the outgrowth of a fatal swamping accident several years ago in the UK. The FISA standards are a complement to good judgment and having a safety plan/equipment readily available. Please review the complete FISA flotation standards to become familiar with the minimum safety requirements. Read more to learn how Vespoli is exceeding these standards."

SingleMinded

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Apr 2, 2014, 2:40:37 PM4/2/14
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Back on this side of the Atlantic, I noticed a plate on a 2004 Burgashell single in the boathouse yesterday. It gave the "average" and "maximum" crew weights, and said that the boat would support a crew of the average weight with a 16cm freeboard when swamped.

Carl: Do you know if this is based on testing? Is this the sort of thing you're advocating?

I also don't know when Burgashell brought it in. I have rowed older Burgashells that didn't have such a plate. I have never seen another boat, from any manufacturer, that has one. I imagine some of those boats, especially singles, do already meet such a requirement...

Carl

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Apr 2, 2014, 3:18:31 PM4/2/14
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Good questions.

No one was plating boats for supposedly safe crew weight before the date
which you indicate, AFAIK. And I don't know what if any testing was done.

However, singles are the one class of boat with really large excess
flotation capacity. When swamped they'll generally hold less than 20kg
of water in the footwell, yet they have a larger ratio of enclosed
volume to all-up weight than any other shell class. So a typical single
has the buoyant capacity to support a crew of ~3 when swamped, making
certification redundant. Doubles also have abundant buoyancy & can
easily carry one extra person. The problems arise with fours and, even
more so, with eights - the ratio of enclosed & enclosable volume to
all-up weight decreases markedly as you move to boats with more crew.

For anyone competent in hydrostatics the calculation of flotation
potential for a shell has always been a relatively straightforward
matter. In recent years it has become easier, given the good
hydrostatics software now available. However, you need an accurate 3D
CAD model of the shell, which means careful & expert measurement, & you
need to know its rigged weight. Then you can accurately calculate how
it will float when swamped with a seated crew of known weight by
computing its external waterline (in depth & fore-aft trim).

What real life testing does, or should do, is to verify the analysis &,
perhaps, expose defects in construction not detected in the measurement
process. But good practice gives highly accurate results: no one
expects a new vessel to have to be tested afloat before marking the
waterline, or a new aircraft to have to be built before its performance
and carrying capacity can be calculated.

craigr...@googlemail.com

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Apr 3, 2014, 5:31:28 AM4/3/14
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I caught the BBC's trailer for the Boat Race this morning - an animation more akin to Surfboat Racing!

Craig.
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