Anchoring and Roll Stoppers

(Posted 10/28/2016)

(See bottom of this page for post-voyage updates)

Anchoring:
Our primary anchors will be a 15-pound and a 25-pound Mantus anchor.  Although we'll probably pick up a couple more anchors before leaving, the Mantus anchors will be our primary ones.  These are the new generation spade-type anchors that have rapidly become the go-to anchoring technology because of their superior holding power in a wide variety of bottoms. 

Most of our anchorages will be in the tropics where coral heads abound.  Traditionally, an all-chain rode has been considered the best for anchorages with coral, as they're not subject to being cut by the coral.  For our purposes though, all-chain rodes have a couple of disadvantages.  One is that the weight would be prohibitive in a boat as small as Minimus.  The other is that chain is known to damage coral, an increasing problem in water frequented by cruising boats.  

Instead, we'll be using 40 feet of 1/4" galvanized chain and 300 feet of 1/2" 3-strand nylon rope on each anchor.  To keep the nylon part of the rode up off the bottom and away from the coral heads, we have a number of small floats, each with 50 feet of rope, that can be attached to the nylon rode every 50 feet or so along its length so that the nylon rope portion of the rode is raised 20' or so above the bottom.        

Roll Stoppers:
Ballasted monohull sailboats in anchorages subject to ocean swell often have a tendency to set up a rhythmic roll that makes life on board challenging.  Decades ago, I sailed a 20-foot ballasted monohull down the west coast from Seattle to Southern Mexico.  After experiencing one too many exhausting episodes of rolling, I built two roll stoppers.  These were not just roll reducers, they virtually eliminated rolling. 

Looking out over anchorages from then on, a frequent occurrence was to see every boat rolling back and forth.  Every boat except ours that is, which was dead still, like it was glued to the bottom.  The roll eliminators were just like the one in the photo below.  We'd anchor the boat, row ashore, fill the drawstring bags with beach sand, then row back, attach the sandbags to the roll eliminators and deploy one on each side of the boat.  Each was suspended from the end of a 6 foot long outrigger and that was the end of the rolling.    

On this voyage we'll also be using roll stoppers, but without the outriggers, as they are harder to fit on Minimus.  Instead, we'll suspend them directly over the side of the boat, about amidships.  Since they'll have quite a bit less leverage without the outriggers, we've made them larger.  My recollection is that the original ones were 18 inches square, whereas these are 28 inches square. 

Like many aspects of our equipment, we hope to report on their performance as the trip unfolds. 



Mantus anchors with chain and nylon rode in anchor bags.













Roll stopper made from 1/2" plywood 28" square, some nylon rope and a
drawstring bag.  Bag is filled with beach sand before use.  Two roll stoppers are used,
one on each side of the boat.




Post-voyage comments (updated 10-14-2017):

Anchoring:

Our Mantus anchors get a big thumbs up.  Granted, we usually had good holding conditions, either sand or mud, but other sailors using them also reported being impressed with how quickly they set and how positively they held. 

If we had a problem, it was that they held too well in mud.  In Hiva Oa we were anchored bow and stern due to limited room to swing.  The bottom was mud and frequent squalls put high stresses on both anchors.  When we tried to pull up the 15 lb. stern anchor, it was so deeply set that we were unable to budge it.  Fortunately another boat in the anchorage had a crew member they called "the winch."  Even he, along with two other young, strong crew members, had quite a struggle getting it up.   In sand bottoms the anchors were much easier to retrieve.

 If we were to anchor again in the tropics where coral is prevalent, we'd be inclined to use all chain rather than chain and nylon rode.  In anchorages where the water was clear enough to see the bottom, we made sure not to anchor near coral heads.  As a result, we never had to use floats to keep the nylon rode off the bottom.  Still, one sleeps better knowing there's no chance of the rode being chafed through.  While we were in French Polynesia and again in New Zealand, we saw 6 mm galvanized chain for sale that was considerably lighter weight than the 1/4" proof coil chain that we had.  100 feet or so of it on each anchor would have been a good choice. 

Roll reducers:

Our roll reducers didn't perform as well as we'd hoped.  This was mostly due to the fact that they were deployed over the side of the boat rather than from the ends of outriggers.  As a result, they didn't have nearly as much leverage as they had on my last boat where they worked so well.  Another contributing factor was that initially we filled the ballast bags with what turned out to be relatively lightweight volcanic sand.  When we later replaced it with heavier pea gravel, the greater weight sank the boards more quickly and the system was much more effective.

In Nuku Hiva, where we spend nearly two months during my illness, marine growth, barnacles mostly, covered the boards and ballast bags.  It was quite a chore to get them cleaned up. 

For my further thoughts on the subject of reducing roll, see our updated "Sailing Offshore on a Micro-Budget" page.     

    

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