Transcript S Ch 06 Anchoring Mooring and Rafting

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Seamanship
Chapter 6
Anchoring, Mooring
and Rafting
1
Learning Objectives
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This session is intended to acquaint you
with:
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anchor types and equipment
anchoring techniques
locations for effective anchoring
mooring and rafting
2
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Anchoring
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The skill of securing
the vessel to the
bottom
3
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Anchors
4
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Bottom Conditions
5
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What do you need?
Many boaters carry several
anchors of different sizes
and types
6
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Fluke Type Anchors
7
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Claw Type Anchors
8
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Plow Type Anchors
9
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Mushroom Anchors
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Mooring
Dinghy
anchor
10
Grapnel
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closed
open
11
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Anchor Storage
12
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Anchor Rode
Rode is the entire length of anchor line or chain
between the boat and the anchor
13
Nylon vs. Chain
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Nylon (et al)
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Less costly
Lighter in weight
20% or greater stretch
Shock absorber
Easier to work with
Heat stress failure
Wear and abrasion
Some UV damage
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Chain
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Expensive
Heavy and heavier
Rugged
Resists wear and
abrasion
Deep catenary
Holds bottom
Does not stretch
Non-absorbing
May need a hoist
May bow down trim the
boat
Corrosion potential
Gloves
14
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Anchor Chain
Strength and weight differences
Link Size
Safe Working Load (lb)
Breaking Strength (lb)
Weight per 10 ft (lbs)
3/16
750
3000
3.9
¼
1250
5000
6.3
5/16
1900
7600
10
⅜
2650
10600
14
½
4500
18000
26
⅝
6900
27600
38
3/4
9750
39000
55
5/16
1900
7600
12
3/8
2650
11000
17
1/2
4500
18000
30
Proof Coil
BBB
15
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Correct Anchor Size & Weight
Check your manufacture’s recommendations
Under what conditions will the anchor be used?
Storm anchors – increase the weight and size of rode.
Boat
Length
Chain
(ft)
Size (in)
Rope
Size
(in)
Fluke Type
Plow Type
Galvanized
High
tensile
Aluminum
Hinged
Non-hinged
Claw
Type
Up to
25
¼
3/8
8 lb
6 lb
4 lb
25 lb
9 lb
11 lb
25 - 36
¼
½
15 lb
14 lb
7 lb
35 lb
14 lb
16.5 lb
28 - 40
5/16
5/8
22 lb
25 lb
10 lb
35 lb
22 lb
22– 33
lb
35 - 46
3/8
¾
43 lb
40 lb
15 lb
45 lb
35 lb
44 lb
45 - 70
1/2
1
70 lb
21 lb
60 lb
66 lb
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How much Chain and Line?
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Typical anchor system
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Chain at anchor
Line to boat
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Scope – Line/Chain
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Scope
19
>>
Scope
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Line/Chain combo
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7:1
10:1
5:1
nominal
storm
light conditions
All Chain
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3:1 – 5:1
20
Why Chain?
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Prevents chafe on bottom
Hold anchor stock horizontal
Enhances catenary
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How long?
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1/2 to full length of boat for combo
More is better
21
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Catenary - Line
Natural catenary – provides cushion
Straightens under wind and wave conditions
22
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Catenary - Chain
Chain contours bottom
Peels from bottom under wind and wave conditions
23
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Anchor Sentinel
Sentinel – weight deployed on anchor rode
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Alters catenary to flatter position
Sentinel suspended and held in place by line: “Preventer” (red)
24
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Snubber
Snubber – section of line allowing chain to loop
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Serves as a “shock absorber”
25
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Anchor Windlass
Lock
Switch
26
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Shackle, Swivels, Thimble & Hook
27
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Chafing Gear
28
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Identifying Anchorages
29
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No Anchor Warnings
No Anchor
Areas
30
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Single Anchor
31
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Lowering the Anchor
32
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Anchoring
33
>>
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Confirming Hold
34
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Weighing & Retrieving Anchor
35
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Retrieving the Anchor
36
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Two Anchors
In tight quarters
two anchors may be
required to control
swing
37
Two Bow Anchors
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Scope 7 to 10:1
30° to 45°
38
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Bahamian Mooring
In confined space two bow anchors can be used
Plan for
your
swing
room
39
Overnight Anchoring
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Same basic consideration for any
anchoring situation
40
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Fouled Anchor
41
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Trip Line
42
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Mooring Approach
43
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Leaving a Mooring
44
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Raftup
Socialization on the water
Boaters can safely move from boat to
boat
Planning and permission required
45
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Fenders
46
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Side by Side Rafting
47
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Stern to Stern Rafting
48
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Rafting in a Circle
Good manners and
courtesy are important
during raftups.
49
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