running a cat3 charter rib, skippering a 40ft race boat, building ribs for a living and manufacturing stainless gives me quite a unique perspective on vibrations on a boat, stress cracks on stainless are mostly due to this.
i'll bow to someone else experience when they can provide me with some concrete evidence rather than a load of quoted figure that have, i doubt, never been applied to a rib.
ive seen this happen so many time before in other industries and it just dies away because it's unworkable, a number of years back there was a similar thing with the guys doing the road works and the concrete breakers, they came up with load of stuff but could never find a better way to use the breakers, so it all disappeared.
like i said i'm all for safer boating but it seems to be safer you'll have to pay for the seminar, i think i'll carry on as i have done, common sense has worked for me