Pic

Pic
A Gear Shift for Oars, Courtesy of Chris Cunningham, Small Boats Monthly

Sunday, August 7, 2016

Anchoring...

Introduction

This post is focused on anchoring  row cruisers, boats about 12’ to 18’ (3.6m to 5.5m) long, weighing 100 to 250 pounds (45kg to 115kg), plus crew/equipment weight and with low windage.

Anchors 

…what are some anchors appropriate for row cruisers?


Sea-Dog Claw Hook Anchor

This light-weight (2.2 pounds, 1kg) anchor is available at Duckworks. It is appropriate for a “lunch hook”, not for overnight.

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Mantus Dinghy Anchor

The Mantus Dinghy Anchor weighs just 2 pounds (.9kg) and is suitable as a 'lunch hook'. Notice that unlike other Mantus anchors (below), there is no hoop to 'right' the anchor, but rather just a straight rod.

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Mantus Anchors Keyed to the Chart Below

The Mantus 8 pound (3.6kg) and 13 pound (5.9kg) portrayed above is sized as stated in the table below:


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Rocna 33 Pound (15kg) Anchor

Rocna has both a 9 and 13 pound (4kg and 5.9kg) anchors that look like the image above.

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For a detailed review, with photos, of a wide variety of anchor types, see Christine DeMerchant’s  Table of Anchor Types.

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Note: Some anchors, such as the Rocna Fisherman’s Anchor, have a ‘shackle rail’ that enables the shackle that connects the anchor to the chain to slide from one end of the anchor shank to the other (blade) end. This enables the anchor to be ‘broken loose’ from the bottom by pulling on the blade end of the anchor rather than the shank end. These types of anchors are very effective as a ‘lunch hook’… temporary anchoring during the day. However, these anchors should never be used for overnight anchoring, because a wind/tide shift can move the boat in the opposite direction from where it was anchored and break the anchor loose rather than pivoting the anchor to the new direction.

To be able to break out an anchor (without a 'shackle rail'), you can attach a line to the 'fluke end' of the anchor (many anchors such as Rocna provide an attachment point for this line). The line should be at least as long as the deepest water you will anchor in and have very visible float on the end. This line will (hopefully) enable you to retrieve an anchor that, for example, is jammed under a rock.

Anchor to Boat Connection

…how is the anchor attached to the boat?

Here is a summary of the recommendations gleaned from many sources:

  • The anchor end of the warp should be 10 to 20 feet (3 to 6m) of ¼ inch (6mm) chain, which fulfills two important needs:


  1. Helps protects the rest of the warp (which is rope) from being cut/abraded in the most vulnerable area next to the anchor
  2. Provides weight at the anchor end of the warp to help hold the shank of the anchor low, which, in turn, helps keep the anchor from breaking loose.

    According to First Chain Supply, the ‘working load limit’ of ¼ inch chain varies from 1300 to 3150 pounds (590kg to 1429kg) depending upon which chain you purchase.


  • The remainder of the warp should be nylon rope…Nylon because of its abrasion resistance and its ability to remain strong when stretched (up to 30%). For oar cruisers, either


  1. quarter inch (6mm) 1,486 pounds (674kg), minimum breaking strength or
  2. three-eighths (10mm) 3,240 (1470kg) minimum breaking strength according to Web Rigging Supply.

    NOTE: It is better to NOT use thicker (than 6 or 10mm) nylon rope because it will not provide sufficient ‘elasticity’ needed to ease the peak loads on the anchor as the boat surges due to wind and waves.

    How much rope warp? The general rule is that the rope warp should be seven (7) times the distance from where the warp leaves the boat (typically the top of the fore deck) to the bottom at high tide. For example, if the bow is 18 inches (457mm) above the waterline and the water is 10 feet (3m) deep at high tide, then the amount of rope warp to be paid out should be 7 times 11.5, or 81 feet (25m). How much rope warp you carry depends on where you typically will be anchoring.


  • All connections in the warp must be of highest quality, stainless steel (or galvanized) and sized correctly for the chain and rope:


  1. Anchor to Chain: Use a shackle such as these from Duckworks   with the ‘pin’ wired to the shackle (called “mousing”) so that it will not twist off.
  2. Chain to Rope Warp: Use another shackle (as in Anchor to Chain) attached to a thimbled eye splice, nylon rope warp.

    The thimble should have two whippings, one on each side of the thimble, to hold the thimble in the eye splice loop as the nylon rope stretches. (I had an anchor line almost part on me when the thimble came out of the eye-splice loop and the shackle was close to wearing through the eye splice.)


  • Rope Warp to Boat: Typically, the warp is brought over a bow chock such as this one  from Duckworks.

    It is critical that the chock be strongly fastened (bolted) as close to the edge of the deck/gunnel as possible to ensure that the rope warp does not rub against a sharp edge as it leads down to the water.

    The rope warp is then lead to a (through bolted) horn cleat such as these that is accessible from the cockpit.

Anchor Rigs

…how do I make the anchor accessible from the rowing position (cockpit)?

In most oar cruisers (and many other small cruisers), the bow of the boat is often at the end of a narrow deck that can be treacherous to crawl on. Setting and retrieving the anchor needs to be done from the cockpit, yet the anchor line must ultimately be lead from the bow of the boat.

Here’s one way to enable anchoring from the cockpit, yet have the rope warp lead from the front of the deck:
At home, make up a light ‘tether’ line about 15 feet (4.5m) long with either a loop or a steel ring such as this on one end. Install a small cleat on the deck near the cockpit. 
Before leaving the dock/ramp, place the anchor, chain and rope warp (coiled in a figure 8 to eliminate kinks in the line) in a box or bucket with the rope warp on top. 
Run the anchor line though the loop/ring on the end of the tether line, forward to the bow chock and then back and hitched to the anchoring cleat (that is bolted securely to the boat). 
Tie off the other end of the tether to the small cleat. 
When anchored, pulling on the tether will bring the rope warp back to the side of the cockpit so you can lift out the anchor and stow it.
Sometimes, you may want to anchor off a beach, and yet be able to bring the boat up to the beach to get ashore, leaving the boat firmly anchored a short distance off shore.

Joel Bergen, in his “Joel’s Navigator Site” (an excellent source for a wide variety of “tips and tricks” focused on building, outfitting and cruising in small boats (including his Welsford Navigator) recommends this technique for anchoring off a beach, yet providing “dry” access to the beach. I’ve copied the diagram below… see the link for a narrative description on how to set it up and use the technique.

Beach Anchoring Diagram

Anchoring


…how do I set and retrieve the anchor?

Setting the anchor:

Make sure both the ‘tether’ AND the end of the anchor rope warp are firmly cleated (ask me why this is REALLY important). Place the coil of rope warp on the cockpit floor or deck. Slowly drop the anchor over the side of the boat, paying out the chain and rope warp slowly as the boat moves back due to wind or tide. (Note that the loop/ring on the tether will move forward of the bow and is to have NO strain in it). (Note: do NOT throw the anchor and chain overboard… high probability that the chain will fall on top of the anchor and the two will become tangled.)

When sufficient rope warp has been paid out (aka “scope”), re-cleat the rope warp securely to the ‘anchoring’ cleat. You may have to row away from the anchor to securely set it. Ensure that the anchor has set by taking two compass bearing to fixed objects ashore.

If sleeping aboard, set an alarm every hour and check that the anchor has not dragged. (I was in a 38 foot cruiser that was anchored in a fully protected cove with just a gentle breeze… plenty of scope with a heavy Danforth anchor. It dragged. One fluke on the anchor had impaled an empty Clorox bottle and could not properly dig in.)

Retrieving the anchor:

Untie the rope warp from the anchor cleat (and then cleat the END of the warp to the cleat). Pull the boat forward using the rope warp (the ‘tether’ is still loose) until the boat is close to the anchor… re-cleat the rope warp. Pull on the tether to get the rope warp and chain to the side of the boat at the cockpit. Haul the warp, chain and anchor aboard. Re-stow the anchor, chain and rope warp (in a figure eight coil) in the anchor box.

See both John Welsford’s and Christine DeMerchant’s articles referenced below for detailed explanations of anchoring.

References


"Staying Where You Want to Be" by John Welsford
In his article, John recommends that the minimum anchor for overnight is 15 pounds… it’s not a function of boat size (nor boat weight) but rather that the anchor is heavy enough to bury… he suggests using 20 feet of ¼ inch galvanized steel chain and 150 feet of Nylon and recommends two different anchors to handle different bottom conditions. The article includes his own story of anchoring during a surprise storm and the lessons learned.

Also see this article by Christine DeMerchant for a thorough and practical article on how to set and retrieve an anchor. (This is another site which is well worth perusing.)


Let me know of other tips and techniques you have for anchoring. For example:

How do you rig the anchor so you can set and retrieve it without climbing onto the foredeck?

How do you store the chain, rope warp and anchor?

Note: In July 2016, there was a  thread in Can-AmDinghyCruisingAssociation@yahoogroups.com regarding storage of anchors in larger cruisers.

12 comments:

  1. Tom - I use a 5 lb Bruce with no chain as my overnight anchor on the Sacramento Delta, and stow it on a home-built bow roller:

    https://www.flickr.com/photos/ricks_boats/27639989572/in/album-72157669392792571/

    I get away with this because the Delta has plenty of sheltered anchorages and a very constant summer wind direction. Also the low profile tent and no masts means not much windage compared to sailing boats.

    The Delta is very muddy, so stowing on the bow with no chain keeps most of the mud out of the boat. The rode goes in a plastic bucket which has a perforated lid put at the bottom to let the rode drain, and a corked hole to drain the bucket.

    ReplyDelete
    Replies
    1. Rick, when you anchor, do you keep the rode in the bow roller, or do you keep it in one of the bow chocks?

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    2. Bow roller usually. It can be handled standing behind the dodger. I also have a 10 lb Danforth with chain and a sea anchor, both get some use in certain conditions.

      Joel's clothesline rig is good, but I've found one of those "anchor buddy" stretchy lines simpler to use. Setup is anchor, 20' line, anchor buddy, 150' line. Drop and set the anchor 50 to 100 feet offshore, then row to shore letting out the line. Standing on shore pull the line to stretch the anchor buddy. Tie off line at a bow cleat, then let out line to allow the boat to be pulled about 30' offshore. Secure the shore side end. The boat can be moved in or out as needed.

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    3. This means that you are depending ONLY on the strength of the anchor buddy to hold the boat. If the anchor buddy is 14' compacted and 50' stretched, what if you attached both the anchor buddy AND the rode to the anchor, then attach the other end of the anchor buddy to the rode 49' feet from the anchor? This way, you have the safety of the rode in case the anchor buddy breaks... What brand anchor buddy do you use?

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    4. You could do that, but it leaves a big loop of line that can catch snags. If the anchor buddy fails the boat is still held by the shore line.

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    5. True, but also you lose your anchor, unless it is buoyed (which "good practice" says it should be)...

      I was reading the reviews for one of the anchor buddies and one person said their anchor buddy broke the first time they used it... no details... but still scary... and why my questions on this.

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  2. One more comment: I have been using a 3-strand anchor splice to attach rode to chain or shackle, not a thimble. An old salt advised that a thimble actually holds the line out where it can chafe faster. The splice is easy to do and slides neatly through a roller.

    ReplyDelete
    Replies
    1. What is a "3-strand anchor splice"... It's not in Grog Knots (my favorite 'knot' app for the iPhone)? Is it like and 'end' or 'back' splice with the 3 strands of the crown passed over the shackle before starting the 'tucks'?

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    2. This one:

      http://www.samsonrope.com/Documents/Splice%20Instructions/3Strand_C1_Rope%20to%20Chain_AUG2012_WEB.pdf

      If you see wear on the line it's easy to cut back and re-splice.

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    3. Thanks for the link... better than a thimble and eye splice... Tom

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  3. Just for interest here is Neil Moomey's clothesline anchoring system for big tide and rocky bottom Alaska waters. He uses floating line to stay off the rocks, and a "pulley" made of big PVC pipe to clear weeds. I've thought of trying it but it seems like overkill for my waters.

    http://www.neilmoomey.com/howtos/anchor_buoy/AnchorPulleySystem.pdf

    ReplyDelete
    Replies
    1. In the conditions he has to anchor in, it's an interesting solution...

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