Mega Yacht Anchors

Hi,

Here is an example of different types of smaller anchors:

http://www.ukdivers.net/boats/anchors.htm

and one for the larger ones

http://www.blueoceantackle.com/hhp_delta_type_anchors.htm

anchor sizing

The size of the anchor is based on the equipment number. This number is calculated from a formula taking into account: total displacement (for influence of the currents) and the windage (area of the yacht above the waterline subject to the wind). For the windage, the area as seen from the bow counts twenty times as much as the area seen in profile, which is quite logical.

Every class society has their own tables giving appropriate anchor sizing with regards to the equipment number, taking into account certain reductions (anchor types, number of anchors, service restrictions, etc.). While for ships these rules are practically the same in all class societies, for yachts every class society has their own mind.

For boats < 24 m, there are different rules (CE, e.g.).

PS. Even with gyrocompasses and gps, we still have magnetic compasses all around. I guess it would take forever before a simple and useful system like an anchor would dissapear from ships/boats, even if they were only used in extreme emergencies.

Hi,

Yes, you are right.

Here is a link that shows a variety of chains and shackles etc asociated with Anchor Chains

http://www.h-lift.com/anchorchain.htm

I am quite sure they're not for hydrodynamics. I see them doing more wrong than right in that respect. It's not like on a planing hull where you can have spray strakes because you want the flow to separate from the hull at a certain point. On a bulb, you don't want the flow to separate.

Why some ships don't have them is a tougher one... Maybe because their anchor pockets are further aft. Or because they hardly ever spend time on anchor and don't want the hydrodynamic penalty. Or they have thicker plating in the bulb...

Why do some cars have plastic guard stripes on their doors and others not?...

Unless they're amphibious of course

Equipment number

Anchor type, size and number as well as chain size and length is determined by the Equipment Number defined by the classification society. This number is calculated by the naval artichect from the lines drawings of the hull taking into account the frontal area of the vessel to determine the pull by windage. Also will define the size of mooring ropes etc.