IOM Buoyancy or How to Sink your IOM

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Dave Alston
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IOM Buoyancy or How to Sink your IOM

Post by Dave Alston » Fri May 11, 2018 12:13 am

IOM Buoyancy or How to Sink your IOM

I came upon a post on IOMIC forum about fitting buoyance bags into an IOM, not a new concept by any means. and as usual how the Class Rules do not specifically permit such buoyance bags and therefore are not permitted. The usual ...


I thought that it might be more interesting to discuss WHY/ HOW an IOM can take on water so quickly and sink rather than Rule Changes and to share my Near Miss experience.

I have a V9 and love it to bits, the infamous 11.

The hatch cover is a polythene re-sealable food container lid as you would find on Baby Formula Container or Gravy Granule Container.


My Near Miss

The main sheet between the Sheet Post and the Deck Pulley became snagged under the flange of lid when I spent some time head to wind with lots of sheet flapping about in the breeze.

When I sheeted in, the boat took off on a port tack but the lid was pulled off by the sheet and a tonne of water came in very quickly. I saw this happening because I was only 15 meters or so away from the boat so I freed off.

RMG winches have incredible pulling power.[ i]

Fortunately I was sailing at Bournville, a small freshwater pond and I made it back with some freeboard. The rugged RMG winch did not seem to mind running immersed in fresh water but died later today.

I have sailed this boat for 4 1/2 years or so, in at least 2450 heats and this has only happened 3 times.
I do keep a rough log of event sailed so I can understand boat and traveling cost. I have reached the point where the boat cost 70 pence in each heat.

On at least one of these occasions, the popping off lid was caused by MY not being fastidious about ensuring the lid was properly fitted and once I actually trapped the sheet under the lid.

One might suspect the other reported incidents of boat losses are related to this remote set of conditions. Many current designs have adopted the polythene Baby Formula Re-sealable Food Container lid in preference to the Honey Jar with screw on lid.

No Criticism, I much prefer this approach, it provides better access and removes the need for deck patches for access.

Deck patches can and do come off if you apply / reuse them on a wet deck , as we all have done from time to time.

What near misses have you experienced ?

Do you know the secret of which product is sold with that size of Re-sealable Food Container lid ?
I have spent ages wandering around Tesco and ASDA with a vernier calliper, they are used to me - its a small town thing

Dave

Nigel Winkley
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Re: IOM Buoyancy or How to Sink your IOM

Post by Nigel Winkley » Mon May 14, 2018 12:49 pm

I have never come close to loosing a boat but have seen an IOM go down to be never found again and in the last six months have seen divers recover a couple of Marblehead.

As the V9 was built in NZL, the chance of finding the replacement lid is virtually zero. Send Ian an email and have him drop a replacement in the post. I had a similar issue with my AUS built Marblehead and had a couple of snap on lids sent as I couldn't source a replacement.

I would like to know under what rule buoyancy bags would be prohibited in an IOM!?! Yes they are closed class rules but a buoyancy bag is not an integral part of the boat so I don't see how these would be causing a class rule breach.

Dave Alston
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Re: IOM Buoyancy or How to Sink your IOM

Post by Dave Alston » Mon May 14, 2018 6:00 pm

Replacement lid.

As you say replacement lids are not a problem. I was simply wondering if anybody had cracked the code .

The major export of NZ is Milk products Anchor being the brand name. These polyethylene lids are made by the million and all you have to do is find out what product it is used in .
But that was a bit of a teaser to see what response I got.

AUZ is a different mater, as not much by way of food stuff is imported to UK.

Interestingly I am sitting in Turkey at the moment noshing a can of Nuts and .... the lid is the correct size so it is coming home with me to join my collection.

Rules
Well I was wondering the same thing but to be honest it is of no interest to me because you cannot get 4.5 litres of air in a bags into the bow of a V9 , well I could not, there is no access.

And as I said there is always the ubiquitous Class Rule discussion. As far as I am concerned any bag inserted into the Hull becomes part of the Hull and polythene is a permitted material so ...

Foaming might be a stretch

Val Provoost
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Re: IOM Buoyancy or How to Sink your IOM

Post by Val Provoost » Mon May 14, 2018 9:38 pm

As any measurer would tellyou a closed rule is a closed rule. In simple terms, unless the rule specifically says you can, you cant. Now show me where in the IOM rules buoyance bags are allowed....................

Dave Alston
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Re: IOM Buoyancy or How to Sink your IOM

Post by Dave Alston » Wed May 16, 2018 3:14 pm

See, I told you so
The old Rule thing comes up

As a Measurer in/ of good standing
Any bit that you affix to a HULL becomes part of the HULL unless it is an Appendage. Something that pokes out from the hull
As such the materials the bit is made off is controlled by Class Rules.

So is a plastic bag made of:-

(8) Thermoplastic, which may be moulded, containing only permitted materials.

The answer is YES

You CANNOT foam fill the boat or make a boat out of foam because - This is NOT a permitted Material


On this basis a Honey Jar or a Polythene Food container Lid is affixed to the hull and becomes part of the HULL.

So you cannot have a carbon fibre lid or container.
But since they are Thermoplastic there is no issue

Similarly there is NO mention in the class rules that a Bracket MAY be installed to support the permitted Rudder Servo and or Winch is there.

These brackets are part of the HULL and only restricted by the rules governing the HULL


Agree ??

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