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Posted: 17 Jan 2018, 18:20
by Hiljoball
I just read on the UK forum of another IOM sinking - it nose-dived and probably blew off a deck patch - filled and sank immediately. the boat was 'lost'.

It strikes me that it would be a good idea if we were allowed to put flotation inside the hull - eg ping pong balls, or those inflated plastic packaging pouches.

Such internal flotation would not be a performance factor, but may save a boat now and again.

The closed nature of the class rules prevent adding such flotation as is is not expressly allowed.

Anyone else have any thoughts on this?


Re: floatation

Posted: 31 Jan 2018, 21:29
by Bruce Andersen
I guess that one could use some sort of a sealed bag that, if pressurized, could potentially stiffen the hull and give a miniscule performance advantage

This is a good one to present to the general membership - having seen a brand new V9 go to the bottom recently, I believe the ability to add some protective flotation is a good option

Whether or not a turgid airbag in the bow of the boat gives unfair advantage - doubt that we will get hard data to prove or disprove (but I bet we get a bunch of opinions!)

Re: floatation

Posted: 14 Mar 2018, 19:49
by Jerry Brower
How about leave the rule as is, fix your bubble wrap in your boat and call it a corrector weight. This may need to go to the class secretary for interpretation validation. But way simpler than a political 2/3rds international vote. JWB

Re: floatation

Posted: 10 May 2018, 04:06
by David Alston
I am intrigued.

What / Which Rule. ?

The problem is getting 4.5 litres of air into the bow. ( 4 kg displacement ) in a V9

Try measuring the Volume of the Bow, put the boat stern up and add water.


Re: floatation

Posted: 10 May 2018, 09:09
by David Alston
It is probably more interesting to understand WHY/ HOW an IOM can take on water so quickly and sink rather than Rule Changes.

I have a V9 and love it to bits. But....

The hatch cover is a plastic food container lid. probably for powdered milk sold in New Zealand, but not in the UK

I witnessed my own near miss. with sinking from about 15 metres away from the boat.

1/ The main sheet between the sheet post and the deck pulley became snagged under the flange of lid when I went head to wind with lots of sheet out flapping about.

2/ When I sheeted in, the lid popped off, The boat took off on port tack, same side as the sheet and a tonne of water came in very quickly.

3/ I saw this so I freed off. The RMG winch has incredible pulling power.

Fortunately we were sailing on a small inland pond and I made it back with some freeboard.
RMG winches seem to tolerate being immersed in fresh water

I have sailed this boat for 4 years in about 2000 heats and this has happened only 3 times.

At least one of the occasions was as a result of ME not being fastidious about ensuring the lid was fitted properly.

One might suggest that some of these boat losses are related to this remote possibility.
Many designs have adopted the plastic food container lid in preference to the screw on pot lid because it is abetter arrangement and easier to manufacture giving good access.

This is NO criticism of this , I in fact prefer this arrangement but it would useful to drop the flange into a recess so it is flush with the deck


Re: floatation

Posted: 30 Dec 2018, 17:02
by Bruce Andersen
Bob Wells and I did an experiment using in-hull flotation bags. The text and underwater photos can be found on the IOMUSA.ORG website: ... riment.pdf