What Anchor? - Page 2

Daniel · 04 March 2004, 22:57

Is a grapnel anchor useful for anything? I've often considered carrying a second anchor, probably a grapnel with say 5m chain and 20m rope incase it all goes tit's up???

jwalker · 04 March 2004, 23:01

Quote:

Originally posted by Brian

I scratched my head and couldn't work out why I need nearly double the weight of anchor (for a given boat) if I was going galvanised or stainless, as against half the weight if aluminium????????

Don't know but an aluminium anchor of equivalent physical size to a steel one will be considerably lighter.

Daniel · 04 March 2004, 23:15

Brian, i think JW is trying to say (and i agree) a 10kg aluminium anchor with be much larger (therefore greater holding "power") than a 10kg galvanised one. Hence you you can use a lighter one for the same holding "power" if it aluminium.

jwalker · 04 March 2004, 23:35

Er, no, I wasn't trying to say that but that will also be the case.

Richard B · 05 March 2004, 06:29

Quote:

Originally posted by Daniel
Is a grapnel anchor useful for anything?

Yes and no - I've been out on a friend's RIB and he uses a small grapnel (same size as I used to use on my SIB) on a 6.5 m without any chain. He's never lost the boat! But they don't inspire much confidence.

Now Brian - own up, has Daniel got to the root of the matter here? What's the old anchor on Cyanide?

Bilge Rat · 05 March 2004, 08:10

I thought the more chain the better, obviously on a small rib this is going to be impractical for stowage and weight reasons ?

R

Richard B · 05 March 2004, 08:56

Yes - just highlighting the poor set-up.

Nick Hearne · 05 March 2004, 09:22

Daniel
Hi I use a Danforth style anchor for my main anchor & a large Grapnel as a second it will hold ok but I have found you do kneed more chain/weight (I have had to attach diving weights to the end of the chain to keep it down) than with other anchors! So as a back up you end up with a lot of extra weight!
If you are in to diving they are good for locating a wreck, but that dose not say much for their holding power.
Nick

Brian · 05 March 2004, 11:06

Richard
Cyanide currently has a "toothpick" folding grapnel type with 2 x 5m of chain (fixed in parallel, thus each end of a 5m length is fastened to the anchor and the other end of each length is fastened to the rope), the rope is probably 8 or 10mm and has an unknown length (my guess is 20m). Now, whichever way you look at it that is totally inadequate and certainly not up to the Irish Cruise we intend to embark on in May. Hence my request for advice here.
After taking everyone's advice, I now intend to purchase a 7.5kg aluminium Bruce with 10m of chain and 30m of good 10 or 12mm rope. I ideally want someone to "build" it for me, with shackling at the anchor and rope ends of the chain (so I can alter the anchor point fixing) and with a nice metal lined whipped loop end to the chain-end of the rope. I need to check first whether all that will go into my anchor locker through the small circular hatch.
Richard/JW
OK, now i understand that a 5kg aluminium would be "the same size" as a 10kg s/s one. And therefore offer a similar holding power.

jwalker · 05 March 2004, 11:24

Don't be frightened of chain. It is easier to grip when hauling aboard, it stows very easily, it doesn't wind up like some ropes, it doesn't carry nearly as much water aboard, it's simple to tie markers to for the purpose of measurement, it won't fray, it's very strong, you can shackle directly to it.......
The only down side, for the boat, is it's weight but it's bu**er all for a big rib to carry and it'll help keep the bow down a little into a head sea.

Tell me again why you'd want to use rope.....

John Kennett · 05 March 2004, 11:34

I have always used the folding grapnel anchors because they are easy to stow and seem to work well enough. Normally anchoring a RIB is a short term measure, so choice of gear is not quite as critical as for say a yacht that will regularly be anchoring overnight.

My setup was a 5Kg anchor with ten metres of chain and 30 metres of 10mm climbing rope that I bought cheaply at the Southampton Boat Show. This was easily sufficient for a 7.5 metre RIB and is easy to stow and deploy.

I don't coil the rope, but make it into a "daisy chain" (or caver's plait, or chain sennit) which is very easy to pay out in an emergency without tangling.

Places like Jimmy Green Marine will make up complete anchor warps including splicing, but it's not difficult to do. Splicing octoplait to chain is easier than tying your shoe laces!

John

jwalker · 05 March 2004, 11:48

You should try velcro on yer trainers if laces confuse you!

John Kennett · 05 March 2004, 12:05

OK, I'll rephrase that.

Splicing octoplait to chain is even easier than tying your shoe laces!

Marvellous as it I wouldn't recomend using velcro for that all important chain/rope join!

I'm not sure that I'd be all that keen on your all chain solution either. It would be very heavy to haul up in any real depth of water. You may just be more macho than me though

John

jwalker · 05 March 2004, 12:09

Ah, but it's not as bad as you might think because it's lighter when it's under water.

But I agree. I wouldn't want to haul up a 100mtrs.

DGR · 06 March 2004, 13:47

...so just to get it straight in my head...

Because it is the physical size of the anchor that's important, if I had a 10kg steel anchor, I could use a lighter one of the same size in Ali to do the same job.

I should use as much chain as I can, but probably at least 5 - 10 metres, the rest (20 - 25 metres) being nylon rope.

Is that right?

Oh - and although I am very good at shoelaces, and therefore ought to be able to splice my own anchor/chain etc, does anyone have instructions/pics on how to do it?

Dylan...

Richard B · 06 March 2004, 13:50

Quote:

Originally posted by DGR
splice my own anchor/chain etc, does anyone have instructions/pics on how to do it?

Try this: http://www.jimmygreen.co.uk/chandler...it_splices.htm

DGR · 06 March 2004, 15:14

Thanks Richard!! I think I can follow that.

JK - blimey, what sort of shoes do you wear?!?

John Kennett · 06 March 2004, 19:53

Quote:

Originally posted by DGR
JK - blimey, what sort of shoes do you wear?!?

Slip ons!

Actually the octoplait to chain splice is much easier than it looks in the diagram. When I first did one I had to go back to the book to check because I couldn't believe it was really that simple! The Octoplait eye splice looks a little more involved though . . .

John

Paul F · 06 March 2004, 21:11

Yep it is. I can splice most ropes but avoid that one as i keep getting lost

Jelly · 08 March 2004, 09:08

Brian
I personaly would go larger on on the Bruce and have more chain.
I have a 7.5 Bruce, 15-20m chain and 40 odd meters of octiplait for my 7.4 Redbay and I was thinking of going to a 10Kg.
I would have thought that Cyanide would have needed more and the anchor is there for than a lunch pick ( I 'm looking at a second one for that I can lift

) IMHO its there for the last resort.

If you can splice then ocitplait is possible but label every core and take your time and check as you go - its very annoying to find a fault at the begining when you have finished

on the eye splices

If I can help drop me a pm
James