Anchor Cables

[j.sabourn]

Just a query to those who spent a lot of time on the really big tonnage. The average 10,000 ton Tramp used to have about 7 or 8 shackles on each anchor. Offshore vessels due to the special type of work was not unusual to have 22 shackles or even more on each anchor. Did the really big ships carry any extra cable lengths as against the older type of cargo vessel. To those not off the deck a shackle (cable length was 15 fathoms = 90 feet) therefore 8 shackles = 120 fathoms = 720 feet. Anchoring a vessel a rough estimate on cable used was 3 times the depth of water. However this depends on weather and other circumstances. Cheers John Sabourn

[Chris Allman]

A bit of info about the Queen Mary 2. She has three 23 tonne anchors, of which two are working with one spare. Her anchor cables are 385metres or 1263feet or 14 shackles long and weigh 136 tonnes each. Breaking strain on the anchor cables is 9300kN or Kilo Newtons or 948 tons -force.

Chris.

[John Arton]

VLCC and cape sized bulkers I was on each had 11 shackles port and stbd and anchors weighed 20 tons.
New style high holding power anchors weigh far less and are much more effective.
rgds
JA

[Red Lead Ted]

One thing they all had in common a Shank, an Eye, Flukes, and a Pea or Bill, Just a bit of useless information i thought i might add { But then does everyone know what a Pea or Bill is or were it can be found? no cheating {Google} Re Terry.

[Capt Bill Davies]

An interesting topic.

The Bantry Class (worlds first ULCCs) had anchors of 19 tonnes which was no larger than the VLCCs of the day which averaged 20 tonnes. This was totally inadequate for their size but, there was nothing of their size before them and the naval arcs obviously satisfied class.

Generally, you could always expect one length extra length of cable on the port anchor ie, 13 port and 12 stbd. You needed at least this on visiting certain ports. Scandinavian owners favoured more 15 port and 14 stbd. The King Alex's anchors were 37 tonnes each, and 15 port and 14 stbd.

Brgds

Bill

[John Arton]

RLT
Pea...tip of fluke
Bill...same
Shank..casting that join crown shackle to flukes
All above relate to Admiralty pattern anchors
now for next question
in a stockless anchor what is the weight ratio of the flukes to the shank and what is the angle range that the tripping palm allows the flukes to move through.
Now don't ask me how I know the answers to the above its just some of the many weird and wonderful facts that we all carry around in our heads.
rgds
JA

[j.sabourn]

They reckon the Bruce anchor had twice the holding power of the Admiralty pattern anchor. One Diving support ship I was on had 6000 ft . of wire on each of the 4 anchors, thus enabling the ship to lay its own in a 4 point moor. This is almost a nautical mile of wire on each and usually finished up after laying with about half a mile on each. Also a similar arrangement on a Drill ship I was on. Cheers John Sabourn

[j.sabourn]

The cable itself is a big factor in the holding of a ship at anchor as weight of cable lying along the bottom contributes to this. Thus when this cable isnt cable but wire as it is on some specialized vessels, I suppose anchors with greater holding power, smaller and also easier to handle had to be devised. John Sabourn

[John Arton]

When anchoring a ship I was always taught the following, which served me well for over 20 yrs. and can only remember two occasion of anchor dragging.
The anchor does not hold the ship in position, it is the catenery of the cable that does, the anchor is there to hold the end of the cable securly to the sea bed.
The ideal pattern for a correctly laid anchor is to end up with something similar to a question mark where the ship is the small dot at the bottom of the question mark. As most ships are right handed going astern the port anchor is the most favoured one.
Ideally, after choosing your anchor spot you let the anchor go whilst your ship is still moving ever so slightly ahead and then pay out the cable as she stops moving ahead, the head starts swinging to stbd. and you gather slight stern way. Pay out the cable as the weight comes on it until you have reached the amount you want out. Rule of thumb was 4 times the depth of water plus one for his nibs, so anchoring in 15 fathoms meant you ended up with the 5 kenter joining shackle on the windlass. She is brought up when the full weight has come on the cable and the catenary of the cable has brought her back up towards the anchor, so as the cable is lying in a gentle curve leading down and fwd. Anchoring in any depth of over 25/30 fathoms, walk the anchor back to around one shackle in the water as otherwise when you do let go, the anchor and cable will gain that much momentum that the windlass brake may not be able to hold it and at best you end up with all cable out and it only been held by the bitter end or worse the whole lot disappears into the oggy oggy and you then have to call for divers, report to class as you are now out of class and get tug escort to take you into port with a very red faced captain trying to explain his balls up to all and sundry.
So a.m.'s morning lesson over on teaching how to suck eggs, i'm off for more coffee.
rgds
JA

[Red Lead Ted]

I was just a mere Able Seaman, Way out of my depth i was one of the idiot,s that used to get the job of storing the bloody cable with those idiotic cable hooks. I have lost shoes, boots, cable hooks, alway,s ended up full of shi* as it was washed down as it was brought aboard on the windless. i remember counting the white link,s if my memory serves me right they were every 15 fathom.s {I stand corrected} But one thing i did make sure of when the Chippy/ Bosun let the lot go i was alway,s well clear of the chain ? You never new what would come flying out {Self stoering cone chain locker,s i never come across many at sea} I must have drew the short straw Regards Skipper Terry.