How to stay put in a blow - the good oil.
by John Martin, Island Cruising Association on 21 Oct 2013
It’s when the chips are down you’ll know if your anchoring skills will save you .. .
Throwing down an anchor for lunch is something most people can master sufficiently to outlast the food (although I have seen situations where that wasn't true) but when the chips are down and there's nothing between you an a catastrophe but your anchoring skills, that's when Island Cruising Association organiser John Martin's advice could save your boat, even your life.
It doesn’t matter if you’re out for the weekend, coastal cruising or away exploring the world, what you put on the bottom can be the best insurance you'll ever have - or the worst.
So it stands to reason this is one area in which every sailor, power and sail, would be making a reasonable investment. You would of course be wrong.
Anchoring can be a great spectator sport and watching what some people put down in the expectation of staying put is frankly laughable.
So what do you need? Not all boats are going to need the same set up and some of it depends on the boat and some on what use you’re going to put it too.
Most boats heading out for the weekend don’t need to go the whole 9 yards but should still have gear sized to the boat.
You’re average production boat will usually come with a windlass that will get the gear off the bottom but may slow down a bit if you don’t motor up on the anchor while retrieving it.
But if you want to head further afield then you need to plan your anchor, rode and windlass around the worst case scenario.
Rope verses Chain and the catenary effect:
This is a debate that has raged for years. If you are only heading out for the occasional overnighter then rope and chain are fine, after all, of course you’ve checked the weather and a blow at anchorage is not in the forecast.
Extended cruising is another matter. Sometimes you don’t have a choice and you’ll be out when it’s forecast to get snotty. If your boat can handle the weight up front then it’s all chain in my book and the more the better.
Why? The word is 'Catenary' and it’s the shape the chain takes as it goes from your bow to the anchor. A nice curve is good, as the boat pulls back in a gust the energy is dissipated as it straightens out the chain and acts as a shock absorber, taking snap load off the anchor, snap loading the anchor or pulling the shank up instead of along can literally 'Pluck' your anchor.
Rope and chain gives you only a very limited catenary effect. If you’re heading to tropical waters then all chain is a must. I’ve seen 25mm rope rode sawn through on coral easier than spreading semi soft butter.
You can also help improve the catenary effect by using a 'Kellet'. A Kellet, a good example of which is the New Zealand produced 'Anchor Buddy', acts as a weight on your chain improving the angle of pull on the anchor. This can be of particular use in strong winds, adding a further dampening effect on the rode, or when space is limited the scope can be reduced without compromising your holding.
How much is too much?
The traditionalists would say it’s never enough when it comes to ground tackle. But to be reasonable for extended coastal and offshore cruising we can start with a minimum of three anchors. Your primary should stay on the bow so you’ll need a bow roller that’s set up to handle it. The primary is your all purpose anchor so needs to be of a type that covers the largest range of bottom conditions.
Over the last five or so years the 'Spade' anchor has risen in popularity with Rocna, Manson Supreme and the new Manson Boss anchor the most popular and for good reason, they work. Size your anchor for your boat (size and weight) as per the manufacturer’s recommendation, that goes for the chain size too.
Your second anchor should be a different type of anchor from your primary but also sized to be used as a primary if required. A good choice here would be a Danforth type or Fortress anchor. Both are very good in sand, mud and softer bottoms. The secondary anchor should be set up in the anchor locker, ready to go and for weight considerations often has a chain and rope rode rather than all chain. This allows the secondary anchor to be deployed quickly in the event of a catastrophic failure of the primary.
Your third anchor has a number of uses and can be set up in a number of ways. We use a smaller Danforth and have it set up to use as a stern anchor for those rolly anchorages. It has about three meters of chain and the rest of the rode is Nylon rope. This anchor can also be used as a tandem anchor if your primary isn’t holding in soft bottom conditions by attaching it onto the front of the primary on the 3m chain only.
Another choice for third anchor would be a Fisherman type if the bottom conditions where you intend to cruise are often rocky or kelp covered.
Not all chain is created equal:
Watch out when you are pricing chain as there is some cheep rubbish around and beware of regalvanised chain. The process reduces strength by as much as 30%. From experience, tested Italian chain has the best performance and should be sized to the boat and the anchor you’re using. Remember the bigger the chain the better the catenary effect.
We carry around 100m of tested short link chain on our primary and this sorts out 99% of anchorages. We have the bitter end secured by a length of rope and a shackle that’s long enough to come just above the hoss pipe so more rode, either rope or chain can be added if required.
Bringing it up and putting it down:
If you’re doing a lot of cruising then you’re windlass is going to get some work. In a six month cruise around the islands last year I calculated the average use and came up with a staggering 13 kilometers of chain pulled in over that time and that’s up only.
If you use your windlass to let the chain out you can double that figure. That’s a lot of revolutions on the motor and gearbox. Added to that we often anchor in depths up to 30 meters, add again that middle of the night bail out from a bad anchorage where you’re using the power of the winch to pull the boat forward, some serious gear is needed.
This is one part of the anchoring equation where might is right so think about going up a couple of sizes on what the manufacturer is recommending. While you’re at it buy a spare windlass motor for good measure and service your windlass like you love her.
Above or below deck:
This is a preference issue, mine is above deck. Why? Your anchor locker is one of the most corrosive places on earth. Put salt water and electricity together and watch metal dissolve. We persevered with a through deck unit for a number of years and I was always chasing my tail.
We swapped out for a deck mounted unit and maintenance is now simply new oil in the gearbox and plenty of grease on the moving parts. For any windlass I can recommend a liberal coating of CRC Soft Seal on the motor for a long life.
Snub it or break it:
A snubber is a very useful piece of your anchoring kit. Usually it’s a length or Nylon or Polypropylene rope that will stretch to absorb shock loads. They’re used to take the load off your windlass by hooking onto the chain once you have enough scope out and allowing some 3 or 4 meters additional chain out before making the snubber fast to the Sampson post or a strong cleat.
A chain hook or shackle can be used or if you’re good a ropes a simple bend will do. A snubber will also insulate you from chain noise as it scrapes across a hard bottom.
Now that we’ve got your gear sorted the next most important factor is scope, or the amount of chain you put out. You’ll hear people say 5 to 1 or some other magic figure, for my book if it’s in your anchor locker it’s not working for you. If you’ve got the sea room put it all out, you’ll sleep better.
With the right gear welding you to the bottom it’s often the other occupants in the bay that are your main worry. A medium sized boat dragging, side on to the breeze can take a lot of stopping and can do a lot of damage very quickly so choosing the right anchorage if a blow is coming can be important. Get there early and position yourself for what’s coming, not necessarily what’s happening when you anchor, can also save you some hair loss.
About the Island Cruising Association:
Our motto is 'We make Cruising more Fun' but there’s a serious side too. ICA offers an ever growing knowledge-base of cruising resources and information specific to Extended Coastal (New Zealand and a developing section on Australia) and Offshore, with an emphasis on the South West Pacific. A wide range of fun events, training, practical demonstrations, on the water preparation and back up to assist cruisers to get out there. Membership in the Island Cruising Association is NZ$45.00 per year and membership gives you access to the entire knowledge base. For more information, go to www.islandcruising.co.nz
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