Anchoring & Mooring Flashcards
CQR or Plough Anchor
Drags when pulled hard enough, tilling the sea bed. The CQR’s tip loading is 12-16% of total weight.
Delta Anchor
Drags when pulled hard enough, tilling the sea bed. Deltas (and presumably the very similar Kobra II) have good tip loading, about 28%, helping them to set easily but ultimately dragging at high loads.
It can self launch.
Fisherman’s Anchor
The Fisherman holds well on rock and weed, but its tiny flukes are likely to drag on any other bottom, ruling it out in most anchorages.
Danforth Anchor
Danforths have a large surface area for their weight, thus they hold extremely well in soft-to-medium bottoms. Setting on these bottoms is also good, thanks to sharp fluke tips, at an optimum angle for penetration. On hard bottoms such as packed sand and shingle they may tend to skid without setting. Their only drawback: they tend not to reset when the tide or wind changes the direction of pull. A flat anchor in lightweight aluminium is thus the ideal kedge, but few choose them as a bower anchor.
Bruce Anchor
Sets and holds well in soft-to-medium bottoms, is said to hold on rock, but its long leading edge struggles to cut through weed. Again, big, heavy ones work far better than small ones.
How much chain only should you use when anchoring?
4 x (maximum depth at high tide + free board)
Allow plenty of room behind the boat when anchoring and for the swing, remembering not all boats will turn at the same time.
How much chain and warp should you use when anchoring?
6 x (maximum depth at high tide + free board)
Always have at least 10m of chain between the anchor and warp so that the chain lays on the bed and helps the anchor set.
Allow plenty of room behind the boat when anchoring and for the swing, remembering not all boats will turn at the same time.
How do you calculate the minimum depth of water to anchor?
Boat Draught
+
Minimum water clearance required
+
Fall of the tide (height of tide at the time of anchoring - low water height)
What should you consider when selecting a good anchorage?
- The depth of water at low tide
- The nature of the seabed shown on the chart. Mud and sand are better than rock or shingle
- Shelter from the wind
- Weather forecast in case the wind changes direction
- Space behind the boat
- Whether there is enough room to swing when the tide turns
- Check the chart for a recommended anchorage
- Make sure boat is outside any channel used by other boats, including if it swings
How to set the anchor
After selecting the site for anchoring:
- Prepare the anchor and chain on the foredeck
- Flake out the required amount of chain and secure it to the cleat
- If the area has a fouling problem, add a trip line to the anchor (a small buoy attached tot he front of the anchor to help pull it in the opposite direction to free it). Make sure the trip line is long enough at high tide.
- Motor in direction boat will lie once anchored (usually into the tidal stream).
- Stop boat and let it drift backwards, paying out the chain slowly
- Let boat settle and check if anchor is holding using a transit or a bearing on the beam
- If boat is dragging, let out more chain if there is room and check again
How many anchors should you have?
2 - the main bow anchor and a smaller kedge anchor
Name the 5 main anchor designs
Fisherman - oldest, dismantles to stow flat, poor holding except in weeds or rock
Danforth
Plough or CQR - good for mud or sand, but awkward to stow
Delta - Plough variant designed for self launching and retrieval
Bruce - Good hold in soft ground, awkward to stow
What are two types of moorings?
A floating plastic buouy tied to a ground chain or heavy buried sinker
A marina berth alongside a floating pontoon
How should you approach a mooring?
Up-tide so that you can use the current to stop you
How many lines should you run from the boat to the buoy
One line if staying for a short time
If staying longer, two lines run from opposite bow fairleads
How should you tie up to a pontoon
With a bow line and a stern line
and 2 springlines
Parts of an Anchor
Duncan’s 5 Essentials of Anchoring
- Shelter - NEVER anchor on a lee shore. Check forecast and tides.
- Not prohibited. Not a channel or fairway or fish farm or protected areas.
- Holding - sea bed.
- Depth of water
- Swinging room
How Duncan marks his anchor chain for length
Tape the code on the inside of the chain locker.
Duncan ties silk ribbons on his chain because they don’t foul and will keep their color.
