| Author | Message |
|---|
| tv tom | Post subject: Re: Canoexpo | |
| Posts: 1139 |
|
 | That does look good but as said before, attaching a pulley and rope to a boat ain't that easy and that method uses alot of rope. I suppose if it is a pinned kayak close by it would be more appropriate...? |
Posted:
Mon 18th Feb, 2008
3:39pm |
| Andy | Post subject: Re: Canoexpo | |
| Posts: 578 |
|
 | Is is possible to have a system with no knots? The knot at 3 in your picture will still have 2 x pull force on it. |
Posted:
Mon 18th Feb, 2008
3:46pm |
| Where Am I | Post subject: Re: Canoexpo | |
| Posts: 757 |
|
 | it is not a knot!! just wrapped round the crab twice.
The whole system has 4 to 1 pull on it (i think).
Yeah I mean it seems most appropriate close by but saying that if you have a 20m rope you can use that method easily if you are within 6m of the bank... usually you would be. perhaps what you can do with this is put a sling round the boat (this probably means you will need another crab though) getting anything on a boat is difficult... |
Posted:
Mon 18th Feb, 2008
4:12pm |
| Chris | Post subject: Re: Canoexpo | |
| Posts: 820 |
|
 | 3 pulleys or more friction that makes is worth while, I'm going to give it a go in the garden in a minte... not convinced yet I'm afraid especially with the extra 2 turns around the karb |
Posted:
Mon 18th Feb, 2008
4:29pm |
| Chris | Post subject: Re: Canoexpo | |
| Posts: 820 |
|
 | yeah... |
Posted:
Mon 18th Feb, 2008
5:31pm |
| tv tom | Post subject: Re: Canoexpo | |
| Posts: 1139 |
|
 | yea....what? did it work? |
Posted:
Mon 18th Feb, 2008
5:33pm |
| Chris | Post subject: Re: Canoexpo | |
| Posts: 820 |
|
| I won't be using it on the river, I think the friction is far to great and I carry a couple of pulleys, a good hauling rope (Alpine bag) and good prussics.
Its worth noting that I very rarely use anything like 3:1 advantage.
The latest example being Nicky's boating completely underwater, Emma, Nicky & I attached a rope to her boat and pulled. It didn't come at first so we tried a different position and it came free.
If that had failed I would have used a vector pull before any serious gear came out, and then failing that a 3:1 pulley. With wet rope and cheap pulley the friction in a 4:1 is pretty high, so would go through the circle again, change postion, vector and then around this point the rope will snap.
|
Posted:
Mon 18th Feb, 2008
5:39pm |
| Where Am I | Post subject: Re: Canoexpo | |
| Posts: 757 |
|
| 1.5 turns, basically it is fixing that point so the rope doesn't slip through crab 2 (unless you need to reset the system) so rope only needs to go through (friction is only created by) crabs 1 and 3...
make sense?
I can't help thinking...4-1 is massive and if you need anything that big, it probably ain't gonna be big enough!
(My alpine bag snaps at a tonne... probably something else will go before then!)
it could well be I was misinformed (but it was from a rescue 3 assessor), I will bring it up next (first) wwsr course I do. |
Posted:
Mon 18th Feb, 2008
5:56pm |
| Where Am I | Post subject: Re: Canoexpo | |
| Posts: 757 |
|
| CHEAP CAGS? link |
Posted:
Mon 18th Feb, 2008
6:35pm |
| Paul Smith | Post subject: Re: Canoexpo | |
| Posts: 208 |
|
| Before even looking at the systems the following information is important.
The really question is why do you need to use prussics in the first place?
Prussics, more importantly their diameter, do need to matched the size of rope that you are using. As a rule of thumb, halve the diameter of your throwline and add a little bit. So if you are using a 10mm Alpine line, you should be using 5.5mm or 6mm diameter piece of prussic cord. There is plenty of research around mainly rope access related stuff to show the reasons why.
Also you need to think about the line that you are using, those cheap nookie lines and the like, are in my view useless for anything other than a throwline rescue and even then can be questionable. If you are to consider the need to pull boats (or bodies) out of a pin or similiar you need to be using something with a core. - HF Alpine bag or the better Palm bags. |
Posted:
Tue 19th Feb, 2008
9:51am |
and
