Deadliest Sea - A review

-Captain Lloyd liked to keep  the Coast Guard Cutter Munro upwind and at the ice edge during the fishing season in the Bering Sea.

-Peter Barry, who died when the fishing vessel Western Sea sank, was an Ivy League student.

- A pilot pushing a "Herc" to it's limits is "flying the barber pole".

- Running both the heater and the deicer on a Jayhawk helo requires two generators which reduces it's range.

-The  F/V Big Valley went down after leaving  port early to avoid Charlie Madicott  and the Coast Guard's Alternate Compliance Program.

These were the kind of details that made Deadliest Sea: The Untold Story Behind the Greatest Rescue in Coast Guard History  by Kalee Thompson a great read.

The book tells the story of the Coast Guard's rescue of 42 crewmembers from the F/V Alaska Ranger. The book is mostly about the rescue itself,  the role played by the Cutter  Munro, the  helo crews, it also tells the  story of Ranger  crew members.

I very much enjoyed Deadliest Sea - highly recommended.

K.C.

Alaska Ranger- shitty job shitty boat

Inside the Coast Guard's Most Extreme Rescue Popular Mechanic article by author Kalee Thompson

Scope - Amount Recommended for Anchoring

Catenary Vector Forces 
A ship's anchor relies upon the weight of the anchor chain (also called cable)  to keep the forces acting on the anchor horizontal as much as possible. If the chain, at the anchor, is lifted 15 degrees it is estimated the anchor loses about half it's holding power.  Insufficient scope increases the risk of dragging anchor. Excess scope on the other hand increase the risk of damaging or breaking the chain.

When the amount of scope required is determined, the distance between the end of the hawsepipe and the water is usually  taken into account but  for convenience  the mate usually reports the amount of chain at the waters edge - for example the bow might report "6 shots in the water'.   It  also can be (usually when heaving in)  reported by how much is on deck.

Many references recommend a scope of between 5 and 7 (of chain) to 1 (water depth)

 Nicholls's Seamanship and Nautical Knowledge makes the following recommendations:

"The minimum scope of mild steel cable to use according to depths of water is given by the following rough guide:"

Below 20 m 6 to 8
20 m to 40 m 4 to 6
over 40 m less then 4

A ship  may be required  to anchor in as much as 100 meters of water (for example Fujairah Anchorage) with 10 shots of chain out the scope is less then 3 to 1.

Ultimately the  master must determine how much scope to use based upon his experience.

K.C.

Ground Tackle Details for PCTC

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About 10 shots of anchor chain from a PCTC 
A few details about the ground tackle of a 6500 unit PCTC (Pure Car Truck Carrier or informally a car carrier) - a 200 meter ship

On all ships the term ground tackle refers to a vessel's anchors, chain and windlass.

The anchor:  The anchor type is AC-14    The weight is about 8 tons

AC-14 Anchor

The chain: The chain consist of links, the type of link is called stud link, the size, which is the diameter of the wire used to form the links is 81mm.   The length of an anchor chain is measured in shots. One shot is 15 fathoms or 90 feet (27.4 meters).

Ship's anchor chain ranged out onto the drydock

The port anchor chain is 11 shots - 990 feet or about 300 meters  - total weight is 44 tons.
The starboard anchor is 10 shots - 900 feet or about 274 meters - total weight is 40 tons.

The weight of a 81mm diameter chain is 0.144 tons/meter - the weight of each shot therefore is 4 tons.

Each shot is connected by a connecting link.

Connecting Link

The connection between the chain and the anchor includes a swivel, an end link and a bending shackle

The Anchor shackle and bending shackle

.  Global Security has a web page with good details here.

The Swivel

The windlass: There are two separate,   hydraulically powered  windlass, one  for each side, the windlass is capable of recovering the chain at a rate of about 1 shot (90 feet)  in three minutes.

Scope refers to the amount of chain used at anchor - that will be the next post: Scope - Amount recommended for anchoring.

K.C.

Failure of Anchor Gear on Cruise Ship

Professional Mariner Magazine reports that an 85 kt gust of wind pushed  a Carnival Cruise Ship off the pier where it was moored.  No surprise there. The standard mooring arrangement isn't going to hold a ship with that much sail area alongside in 85 kts .What caught my eye was this:

"The company said the anchor retrieval equipment malfunctioned after the incident."

I don't know what happened to the anchor gear, no details are provided. (It's standard practice to let go an anchor or two in this type of situation)  My guess is at some point during the excitement the anchor gear took a very heavy strain and damaged the anchor windlass. My experience has been that the windlass  will fail before the chain or anchor will. A heavy strain on an anchor windlass can bend the main shaft, or twist the winch so that the main gears are misaligned.

If you are using your anchor gear to hold the ship off the rocks it's a good thing if the chain or anchor doesn't fail. If the windlass fails you'll likely still be able  veer more chain or hold what you've got.

One thing is, after the yelling dies down and  you want to get out of Dodge you're going to have to recover your anchor and chain without the windlass.

K.C.