Anchor Chums

[robbieg]

I'm thinking of making an anchor chum up. Idea so far is get a small plastic bucket, put a few links of chain to fastern a shackle to and then fill with concrete.

Any other ideas for making on of these and any thoughts on weight of the chum for a 34ft lightish displacement sail boat-I was thinking about 15kg.

 

[bilbobaggins]

It's my view that the best way to put more weight down is to carry and use a bigger anchor and more anchor chain - or use chain considerably thicker/heavier than standard over the first 20 metres or so.

A 'chum' or 'angel', if used, needs to made of very dense stuff. Have you an idea of the effective mass of this bucket of concrete ( mass in air MINUS displaced mass of water )? D'you believe it will be effective in its role?

If you're really intent on making a light displacement boat into a heavy-D hull, I have a couple of 56lb steel weights you could use. You could also take a small-diameter car wheel and wrap old chain around its circumference a dozen times.....

/forums/images/graemlins/wink.gif

 

[Poignard]

Buy a sash window lead weight. The supplier will cut you off a piece as heavy as you need.

I bought one from;

Wimbledon Sash Weights
020 8417 1112
Riverside Business Park
Lyon Road
London SW192RL

 

[smudge837]

hi all,

an effecitve way is to locate a small ammunition container, known as a H83. when filled with lead this will weight in at around 45kg. also being metal and a tough little box, they last a long time and can take knocks and bumps well. the handle on top is not suited to the job but a sturdy U bolt fitted through the end works a treat. this also alows for connection point while letting you retrive if needed. if your pass this way i can let you have one no probs, (minus the lead, lol). of course you can vary the content till you get the required weight for your boat.
cheers. /forums/images/graemlins/smirk.gif

 

[jcmmarine]

Addons more problem than they are worth.
What you need is a sufficiently sized/weighed anchor and chain for your boat.
My boat had a build fit 15kg anchor and 6mm chain, and I had problems. Upgraded to 25Kg anchor and 10mm chain and problems went away.

 

[FrancisRutter]

I used to sail on the Broads and there one uses a mud weight instead of an anchor. I kept mine and now it makes a good chum with a large shackle attached which will go over the anchor chain. Worked well on the few occasions that I have needed it.
These are standard items at all Broads chandleries.

 

[jimbaerselman]

[ QUOTE ]
carry and use a bigger anchor

[/ QUOTE ] Endorse that. There's little concrete evidence (groan) that chums do anything to improve ultimate holding power - chains are usually bar taut at anchor pullout forces, with or without chums.

In lighter anchoring conditions where you are only using part of the anchor's holding ability, chums/heavier chain will reduce your swinging room by enabling you to use less scope.

But that won't work if the wind gets up! Less than 4:1 scope will reduce the holding power of most anchors, and pull many out, chum or no.

You can test all these statements yourself. Put aside an 'anchoring day', see what reverse power your anchor will hold at various scopes, and see whether a chum makes any difference. I couldn't find any, except at short scopes when a slightly higher power was needed to pull the hook out (wouldn't hold half power though).

 

[Danny]

So what's the intention with having a chum or angel? Is it to:

1/ make sure that the pull on the anchor is horizontal along the seabed.

2/ provide some shock absorbtion (in addition to the chain catenary).

It seems to me that you can't effectively do both at the same time as, with 1, the chum needs to stay on the seabed and with 2 it needs to be some way up the chain and off the seabed. I, for one, would like to hear how people have deployed them as well as how they've constructed them and how effective they believe them to be.

 

[bbg]

Having used a relatively light weight chum (10 kg), I would not do it again, and would suggest that anyone hoping to use if for shock absorption is misguided.

If the chum is not very close to the anchor, all it will do is promote the boat to surge forward in a lull (as the chum, which has been lifted off the seabed) falls back to the seabed. Next time a gust comes, the boat will be blown back farther before it is stopped by the anchor. The chum will not really slow the boat down, and consequently the boat will be moving faster, and therefore imparting a greater snatch load on all components, than if there had been no chum.

In my opinion the only way a chum will have any value is if it is VERY heavy, and very close (say within 5 meters) to the anchor. Better to invest in a heavier anchor.

 

[BrickSailor]

I use a chum regularly to reduce the swinging room in crowded anchorages. I need to reduce the swinging room because I'm relying on my 25kg CQR and 60m of 10mm chain to make sure my beer-induced slumber isn't disturbed /forums/images/graemlins/smirk.gif

 

[Abigail]

A chum is very useful for reducing swinging room and worth keeping if you are in that situation much. We have one we acquired from a guy who was swallowing the hook, which he made himself. He lived on a cat and said he'd used it a lot.

He set a strong ring bolt into a saucepan and poured led around it till the saucepan was full. The lead set and lo and behold a dead handy and heavy little chum. The ring bolt of course needs to be big enough to hold a shackle that will go over your chain.

 

[saltwater_gypsy]

I have found a chum or angel to be indespensable where you need a long scope with restricted swinging room. I have a 25 kg weight which I geneally lower until it touches the bottom.
Here is an interesting site on the subject:
http://www.johnsboatstuff.com/Articles/anchor.htm

 

[jimbaerselman]

Your quoted article reflects a very simple view of what puts strain on the anchor. He looks solely at the static case, and talks about maximum tensions on the rode of around 680 lbs.

The reality is that, in winds above 25kts, many types of boat sail from side to side of their anchors, snatching at their rodes as they tack. In these conditions tensions of up to 5,000 lb can be generated in all-chain rodes. At this tension, chains, chums or whatever are quite irrelevant; your rode will be a virtually straight line, lifting the anchor shank off the bottom. Only scope will keep it dug in, ensuring that the lift angle is not too steep.

And only a substantial length of nylon snubber (20m plus) will give the elasticity needed to reduce the snubbing forces.

I'm talking here in the context of a 14m sailboat which may have to remain safely at anchor with from 25 to 35kts blowing off shore in flat water. If your anchorages never have these winds, fair enough. Chums may do something for you.

But check it out. If you're a sail boat, make sure your rode/anchor can hold full reverse. Some motor boats, of course, may have too much power for this test!