Checking potential collision course?

Nah, this guy's from Mars , said he with a Snicker!

Sorry not intended to be aimed at anyone .. just an infantile puny response to Fireball!
 
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Angele said:
End of ferry pier: 50deg 45.9min N, 01deg 17.5min W
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The position of the pier doesn't matter one iota. All that matters is that the other boat, at the time you look, appears to be moving past it. If that's the case there will be no crunch as long as your speed and course, and his, don't change after that. But because you're being careful you'll look at him again a bit later and see whether he's moving against the RYS and a bit later still to see if he's moving against Egypt Point. If he continues to appear to be moving ahead against the land, you will go behind him (except you or he would probably have tacked by then!)

When I get the boat out sailing next, I'll try and take a video to demonstrate.
 
Actually Ken, it is possible to collide if both boats each perceive each other to be moving very slowly forward agains the background (thats why I apologised earlier) but practically we would see that as to be so slow as to indicate risk of collision. So Rule of Thumb to guide the wise not an absolute law.
 
Twister_Ken said:
The position of the pier doesn't matter one iota. All that matters is that the other boat, at the time you look, appears to be moving past it. If that's the case there will be no crunch as long as your speed and course, and his, don't change after that. But because you're being careful you'll look at him again a bit later and see whether he's moving against the RYS and a bit later still to see if he's moving against Egypt Point. If he continues to appear to be moving ahead against the land, you will go behind him (except you or he would probably have tacked by then!)

When I get the boat out sailing next, I'll try and take a video to demonstrate.
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Ah - I think I get you - you're looking at a snapshot of say 5 or 10 seconds at a time and seeing if the target vessel is moving forward of a transit against the shore for that specific period - then next time you look you pick a new object as the transit ...

I'll have to try it next time I'm out.... but I'm sceptical that it'll work ...
 
Not eeven that complicated FB, your just cheching if the vessel is moving forward or backward relative to the background land
 
jimi said:
Not eeven that complicated FB, your just cheching if the vessel is moving forward or backward relative to the background land
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yup - I can see what you're saying - I may have done it myself - but I don't recall and thinking too hard about it is telling me logically that it shouldn't work - but I'm probably missing something - hence I'll try it next time I get a chance. (no point checking against ChrisE - he's too slow!! ;) )
 
jimi said:
Maybe Tk's boat, with the additional ballast, holds a steadier course than FB's light and flighty dinghy?
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Probably - no steady course downwind in an RS400 if it's breezy .... :) Not as good as the 800 though ... that was fun!!
 
jimi said:
In this case , I suspect most people would have worked out that risk of collision existed sometime before Crunch
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Not if they are relying on a fatally flawed "rule of thumb" picked up from some website somewhere ;)
 
Twister_Ken said:
Just one more thing (sorry)...

...if you're in the middle of a fleet of boats like, let's say, tacking out of the Solent in the Round the Island race, HTF are you going to keep track of which one of them is a collision risk with a hand-bearing compass?
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You throw it at them and if it bounces back, you probably are?
 
Oh - I wouldn't ... I'd just shout 'Starboard' and let the others worry about it .... ;)




ok - I've not tacked out of the solent in the RTI race - but I have raced in large fleets both as helm and crew - I've always used visual bearings to the target .. ie no compass - but judging by eye - pretty much how everyone does whilst walking/cycling/driving ... and it is much easier for the crew to do this and leave the helm to concentrate on sailing fast - which contributed to Dad and I winning the open series one year (I crewed - or as I like to tell it - I helmed from the front of the boat - it requires a lot of trust both ways - but as he taught me to sail it was his fault really!).
 
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