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Presentation on theme: "SEAMANSHIP CH. 9 ANCHORING"— Presentation transcript:


The study references for this chapter are again found in Chapman’s Piloting, Seamanship and Small Boat Handling, along with this Power Point Presentation and the USCG Auxiliary Student study guide and practice questions.

The process of anchoring is mostly a combination of “a SEAMAN’S EYE and common sense”. What do you want the anchor to do? How big an anchor do you need? Where will you be anchoring? Where will you keep it on the boat? Who will handle the anchor

You want the anchor to HOLD THE BOAT WHERE YOU PUT IT. That implies that the anchor must STAY where you PUT it. It must be light enough to comfortably handle and yet heavy enough to dig in and hold the bottom. It must be designed for the bottom types you will encounter the most. It must hold in all kinds of weather, seas and current.

A mistaken concept is that the effectiveness of anchor depends upon the weight, for it’s holding power. For most Auxiliary vessels ( ft.) a utility – type lb. type is satisfactory. Deeper draft vessels may need a little more. The anchor’s holding power depends on the design. There are anchors designed for every type of bottom known. Try to choose the anchor for your vessel’s weight, handling characteristics, use and area of operation bottom type. They are made from aluminum, steel, cast iron and bronze, depending on the desired use.

6 DESIGN The primary motivation for the design of an anchor, is it’s HOLDING POWER. Most of the characteristics of the anchor reflect it’s ability to “DIG IN” and continue to hold, without turning over, flipping, or simply breaking loose. Additional considerations are its ability NOT to foul on anything it may encounter. Finally, the ease of maintenance feature must be considered.

Bottom type is probably the greatest item of consideration for the TYPE of anchor you will need. Consult your navigation chart in your operating area. It’s printed right on it. Lightweight anchors such as the Danforth-type by Danforth or Fortress, the Plow, the Delta, the Bruce, the Max, the Kedge, the Navy-type and the Grapnels, Folding – types, and the Northill and Mushroom – type are either general – purpose or designed for a limited range of specific uses. Bottom - types such as hard, rocky, gravel, sand, mud, grass or coral are often found in combination and must be taken into consideration for true successful anchoring.

8 STORING THE ANCHOR It and all other accompanying gear such as the rode, should be stored in a location “FOR IMMEDIATE USE” mode. It should remain free of all entanglements or any fouling apparatus. There should be ample room for the rode to run free.

Do not buy an anchor that cannot be comfortably handled by your crew. It will not be a satisfying experience. Consideration should be given to the physical capabilities of the crew including their eyesight, hearing capabilities, their limitations, training and knowledge of the functions and importance of ANCHORING.


Flukes Shank Ring or Jew’s Harp Bill or Pea Arm or Tripping Palm Crown

12 YACHTSMAN’S ANCHOR Almost a generic name for a number of different styles, all lightweight and designed for average holding power. Easy to handle and reliable. The stock enables the anchor to remain orientated so as to maintain its maximum holding power, as long as this is not “broken” by the incorrect tension on the rode raising the shank to too high an angle. Somewhat antiquated in design now but still an efficient anchor.

13 **** Most anchors do rather poorly in GRASS.****
SAMPLE ANCHOR TYPES **** Most anchors do rather poorly in GRASS.**** FORTRESS anchors can be assembled in two ways to enable them to increase their efficiency. They have great holding power and are of lightweight aluminum. The DANFORTH itself is the popular choice. Made from aluminum or steel. Great holding power. Excellent balance. The PLOW ( or CQR): Excellent on wide range of bottom conditions. The BRUCE anchor: Developed for offshore oil rigs it has been scaled down for small boats.


KEDGE – types: The Hereshoff, Fisherman and the Yachtsman. All Excellent on heavy grass or weed bottoms. Also commonly used to “kedge” a grounded boat off the bar. NAVY – types: Not the best for small boats. They must weigh far too much before their holding power becomes efficient. Used on big ships because they are flukeless so as to be retrieved into hawse pipes. GRAPNELS: Not recommended for small boats. Good in rocks. Must use a tripping line to free them otherwise, you are permanently attached to the bottom!

16 ADDITIONAL TYPES FOLDING TYPES: Some sacrifice to holding power and strength. Good on rocks and also on grass and weeds when properly rigged. Not too good in soft sand or mud. The NORTHILL: Excellent for stowage. Made from stainless steel. Again, it is a foldable similar to the grapnel in appearance. MUSHROOM – type: The smaller weights are very popular for very small boats, dinghy's, canoes, etc. . The larger sizes are popular for permanent moorings, holding huge vessels in the thousands of tons.

All of the gear, collectively, between the anchor and the boat, is called the “ANCHOR RODE”, whether it is of chain, synthetic fiber or a combination of both. The most widely used material for the anchor line is three-strand twisted or double braided nylon. Chain makes a good rode but the weight is generally prohibitive. DOUBLE-BRAIDED NYLON is elastic. The stretch qualities (15%-25%) make it ideal for stress loads in heavy seas while at anchor. Stow it out of the direct sunlight!

DOUBLE BRAIDED NYLON: Gives exceptional stability without the twisting characteristic of the twisted variety. No kinks. Can be easily faired through fittings and into storage. You need to “fake” it down to prevent a “set”. It is less subject to chafing, but is slightly less elastic ( only about 14 %, compared to twisted nylon ).

19 CHAIN CHAIN is for vessels which would require too large a diameter of nylon for an efficient anchor line. It can be used, however, as a personal choice. In heavy coral or rock areas, chain is ideal and in some cases, indispensable to reduce or eliminate excessively heavy chafing. BBB, PROOF COIL and HIGH TEST CHAIN( the best ): The three kinds of chain most commonly used as anchor chain. CHAIN must be matched to the “wildcat” used to hoist and lower it. IDEAL COMBINATION: Nylon ,with 6-8 ft. or longer length of chain. Chain helps to keep angle of stock very low to bottom for max dig power of flukes.

PREFERRED METHOD to bend the anchor line to the anchor is to thread a shackle through the eye of the shaft; and secure the shackle bolt through the end link of chain. On the other end of the chain, another shackle but this time, secure the shackle pin through a THIMBLE , which has been worked into an EYESPLICE in the end of the anchor line, to prevent chafing. Safety wire the shackle pins to prevent them from turning out. OTHER FASTENINGS: The bowline or the anchor bend or any other acceptable knot may be used but care should be taken to use one which can be broken down easily.

ALL FITTINGS: Should be through-bolted and backed up with steel plates, to reduce the possibility of a strain on the anchor line which has been secured to this hardware, pulling the bolts back through the deck or anchoring surface. REMEMBER: It is the objective of the anchoring maneuver, to keep the boat’s position stationary. If the fittings pull out and the anchor runs free or drags as a result, the failure of the fitting may jeopardize the vessel’s safety.

22 SCOPE DEFINITION: The length of the anchor rode in relation to the height of the bow above the bottom of the water body ( R÷ Bh ) where R = Rode length and Bh = Bow Height of the bow above the water. Interpretation and application: The length of the rode. You know you should have a minimum scope of 5 : 1 but should have 7 : 1 in fair weather. You have 80 ft. of rode out in 10 ft. of water which gives you a scope of 8:1 (80 ÷ 10). However, if your bow is 3 ft. above the water your actual scope is only (80 ÷ 13 = approximately a little more than 6! *** The SCOPE is a MAJOR FACTOR that determines whether you will DRAG or HOLD!!***


One of the marks of a professional seaman are the little plastic tabs with depth numbers on them, which have been inserted between the strands of anchor and towing lines, especially but also for any other line where LENGTH is a key factor. Plastic CABLE MARKERS are inexpensive, permanent, easy to apply and take the guesswork out of length requirements altogether. They also display a distinctive character attribute of the owner; a desire to “do it right”.


1. ALWAYS USE YOUR CHART to pick your anchorage. It’s your “road map” to the area, in detail. 2. Try to pick a bottom that has little or no mud, loose sand or heavy grass, for better holding characteristics for the anchor. 3. Try to anchor with your bow into wind. This will help to keep your sleeping area free of insects living on the surrounding land mass. It also will help in getting underway as you are already heading out and you do not have to turn around! 4. Try to pick an orientation which will give you as much lee as possible, in case of inclement weather.

Keep in mind, if you use only one anchor, you are free to rotate 360 degrees on your anchor during the night or day, possibly over dangerous rocks below or into other anchored boats in the anchorage. Keep this in mind in choosing the spot and when approaching. Use your GPS or suitable range marks you have chosen, to navigate to the desired spot to drop the anchor. Visualize other vessels already anchored and how they might swing or set up in any current or wind, before your final selection of a good spot.


29 LETTING GO THE ANCHOR As a good sailor, your anchor and all the necessary gear is “ready”.That means it is properly and adequately attached with secure fittings, backed, and the deck is cleared for working. STOP ALL HEADWAY. Reverse you engine at idle speed. Just as you begin noticeable sternway, lower the anchor slowly but positively until it hits the bottom on the crown. The goal is to PREVENT fouling.

30 SETTING THE ANCHOR An anchor MUST be SET to yield it’s FULL HOLDING POWER. This is somewhat “trial and error” because every boat is different. Pay out the rode until you get to your pre-selected marker. Take a turn or two around a cleat. Check things out to see if it is holding. Keep doing this until you are satisfied it is holding. When you are satisfied, stop the rode with whatever system you have. Pick out at least two ranges, one on each side at about 45 degree angles to each other and make a note. Your “anchor watch” can detect drift by these sightings later and take corrective action..

31 WHEN THE ANCHOR DRAGS Check the bearings of the two ranges you chose when you came into the anchorage. Be prepared to get underway immediately and to fend off, if necessary. If there is no immediate danger of collision and you have enough room, let out additional scope and test for holding each time. On the engine, bring the bow back into the wind to ease the strain on the rode. If it is reasonable, raise the anchor to clear any fouling that might have taken place.

SENTINEL: A weighted device you can slide down the rode, with an attached “tether line” to control how far down on the rode you want it. This device sets a “sag” in the rode which reduces the angle between the rode and the bottom, making the anchor flukes dig in better; making it more difficult to pull out thus increasing it’s holding power. A length of heavy anchor chain will work good also to achieve the same result. An anchor buoy set midway between the bow and the anchor will also help to relieve the strain on the anchor in heavy seas, and reduce the threat of pulling the anchor out. You can combine the buoy, chain and sentinel if necessary.

Best method is to rig the anchor with a BUOYED TRIP LINE, secured to a ring on the crown and attached to a cleat on the boat, BEFORE YOU LOWER IT. Retrieving this line will break the anchor lose and you can pull it in backwards, further helping to wash grass or mud from it, or breaking it out from rocks. Try running a heavy length of chain down the rode, with a line attached to it. From another boat or dinghy, from 180 degrees to your rode, pull your anchor loose. If the anchor is deep in heavy clay, wait until low water; shorten up on the rose as tight as you can get it and wait for rising water to do the job.

34 GETTING UNDERWAY ALWAYS have your mainsail up and set or your engine on and in gear, for positive control, before breaking the loose from the bottom. Setting in a current, near shore, grass and other like debris will entangle in the anchor rode. Whipping the line up and down in a snapping motion will help clear most all of it. Do not store the anchor line with any of this debris as it will hasten it’s breakdown and carries this moisture down below decks where it is most undesirable. KEEP THE ANCHOR OFF OF THE HULL!

35 USING TWO ANCHORS Use of two anchors, a “working” anchor and a “storm” anchor, will help to correct for deficiencies with only one anchor, when in heavy weather. The STORM anchor can be run out and set without moving the working anchor at all. A careful watch must be kept on the lines to see that they do not become fouled and pull each other loose from the bottom. Cleat each rode separately to different sides of the boat. Deep draft sailboats will lie head into the wind naturally. Power boats and small skiffs tend to put their sterns into the wind, if left alone. It may become necessary to use two anchors with these vessels to keep them out of trouble.

5. Allow for clearing the swing with other obstructions. When anchoring in a tidal or current way, where you know either will change 180 degrees during the anchorage, set two anchors at 180 degrees to each other, with the bow at the midpoint of the two rodes. 6. Two anchors are a must if you wish to orientate your boat in a fixed position. 7. Never dock on the weather side. Considerable damage is possible. 8. Stand off and set two anchors on the outside, to hold you off the weather side of the pier, if practical.

37 RAFTING TO ONE ANCHOR Do not raft to a single anchor in other then very light current or calm wind conditions. Otherwise, one or more of the other boats will cause the single anchor to break loose and ALL will drift. Instead of rafting to the other boat’s anchor, raft to other boat with your regular docking lines. They are easier and quicker to break away with. For SAILBOATS, make certain all rigging, especially aloft, stays clear when rafting. DO NOT leave boats rafted for the night. Each boat should seek their own anchorage for the night.

38 ANCHORING AT NIGHT To check for drift at night, you can set your leadline with a little slack. If it becomes taut, you have drifted and your anchor is dragging. Don’t forget to pick it up when leaving in the morning! Don’t forget your “ANCHOR LIGHT” to meet your boat’s requirements of the Rules. In addition, during the day, if you are required to meet the rule, your SINGLE BLACK BALL dayshape should be flying from your crow’s nest.

39 ULTRAVIOLET At the cost of lines today, you will not need too many reminders of this, but; DO NOT LEAVE YOUR LINES, ANY OF THEM, EXPOSED TO THE SUN’S ULTRAVIOLET RADIATION ANY LONGER THAN ABSOLUTELY NECESSARY. If the line must be left on deck, shade it. Dry them, if practical, and store them in a cool, dry place, preferably your rope locker. Remember: FLEMISH it. FAKE it or COIL it. DO NOT CHORD IT ( gather it into a lump and throw it in a box!)!

40 REVIEW QUESTIONS NO. 1 The most widely used material for the anchor line is_________ a. polypropylene b. polystyrene c. nylon d. rayon

41 REVIEW QUESTYIONS The most widely used material for the anchor line is__________ c. nylon

42 REVIEW QUESTIONS NO. 2 2. All gear, taken collectively, that lies between the boat and it’s anchor is called the _________. a. line b. mooring c. rode d. cast

43 REVIEW QUESTIONS 2. All the gear, taken collectively, that lies between the boat it’s anchor is called the ____________ c. rode

44 REVIEW QUESTIONS N O. 3 3. The lightweight type anchor is excellent on ______ and sand bottoms. a. rock b.hard c. gravel d. mud

45 REVIEW QUESTIONS 3. The lightweight anchor is excellent in _____ and sand bottoms. d. mud

46 REVIEW QUESTIONS NO. 4 4. Chain is designated by the __________ of the material in the links. a. length b. weight c. metal d. diameter

47 REVIEW QUESTIONS 4. Chain is designated by the _______ of the material in the links. d. diameter

48 REVIEW QUESTIONS NO. 5 5. The ideal rode for most average conditions is a combination of _________ and a short length, less than 1 fathom of chain. a. cable b. nylon c. rayon d. polypropylene

49 REVIEW QUESTIONS 5. The ideal rode for most average conditions is a combination of ____ and a short length, less than 1 fathom of chain. b. nylon

50 REVIEW QUESTIONS NO. 6 6. When anchoring under favorable weather and sea conditions and using nylon line, a scope of ________ might be considered a minimum. a. 5 : 3 b. 4 : 8 c. 5 : 1 d. 5 : 1

51 REVIEW QUESTIONS 6. When anchoring under favorable weather and sea conditions and using nylon line, a scope of _________ might be considered a minimum. d. 5 : 1

52 REVIEW QUESTIONS NO. 7 7. When anchoring, the anchor should _____ be lowered when the boat has any way on. a. always b. never c. probably d. must

53 REVIEW QUESTIONS 7. When anchoring, the anchor should____ be lowered when the boat has any way on. b. never

54 REVIEW QUESTIONS NO. 8 8. If an anchor drags, the first step in trying to get it to hold is to_______. a. pay out more scope b. take in scope c. change anchor size d. try another spot

55 REVIEW QUESTIONS 8. If an anchor drags, the first step in trying to get it to hold is to_____. a. pay out more scope

56 REVIEW QUESTIONS NO. 9 9. When chocks, cleats and other fittings are used on deck, they must be _________ and reinforced with a strong backing plate. a. heavily screwed b. through-bolted c. screwed d. stopped

57 REVIEW QUESTIONS 9. When chocks, cleats and other fittings are used on deck, they must be _________ and reinforced with a strong backing plate. b. through-bolted

58 REVIEW QUESTIONS NO. 10 10. The type of anchor traditionally used for permanent moorings is the _______. a. pan b. mushroom c. folding d. navy

59 REVIEW QUESTIONS 10. The type of anchor traditionally used for permanent moorings is the ________ b. mushroom



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