Anchoring in heavy conditions

Patrick,

I don't know of anyone who has done the type of research you are looking at. Frankly it just isn't worth the trouble. Anchoring is a pretty settled area of boating. Use a big anchor, lots of chain, and a snubber.

There are legitimate debates about the use of kellets, best type of anchor, amount of chain to carry, ect. But these are only interesting debates because of the subtle difference in the different theories not because of the lack of understanding of them.

Pick any SHHP anchor, go two sizes up from the manufacturers recommended size, reasonable size chain, drop 10:1 rhode, and your boat will survive hurricanes absent getting hit by another boat.

 

Thank you Greg.

You opinion is decidedly optimistic and then must be of great advise, with no doubt especialy if it is bearing witness.

In fact, I am trying to compare the workmanlike of the "anchoring art" in heavy conditions between the two coasts of our Atlantic ocean.

In addition to your testimony, any literature or Internet link available in your area will be of great interest for me in that way.

Thank you.

Kindly.

Patrick

 

For extreme anchoring techniques you might Google SKIP NOVACK.

He has spent many years running charters in the southern ocean and will be an expert .

His thoughts will be on the internet

 

Hello to all.

Thanks a lot Michael.

I had some personnal discussions with Alain POIRAUD and Alain FRAYSSE.
The first because I equiped my 35 footer with SPADE anchors (steel and aluminum) and the second concerning his excellent public calculation sheets allowing simulations to design anchoring suitable line.
http://alain.fraysse.free.fr/sail/rode/rode.htm

My aim at this point is to try to compare the results between theorical design and pratical measurements especially during heavy conditions because of possible well known breaking line conditions.
In my opinion some improvements are then possibly to be foreseen, if any calculations and measurements meeting available.

Kindly.

Patrick

 

Patrick,

The issue is that almost no one has a problem because the line broke. Their are cases of lines abrading leading to loosing the boat, which is solved by switching to all chain. There may be cases of the chain breaking, but I don't know of any. Usually the anchor drags before the chain breaks.

This is why Steve Dashew, who has most heavy weather anchoring experience than anyone else I know, just uses the largest anchor he can reasonably store on his boats. I think his 64' aluminium FPB uses a 115lbs Ronca.

 

Since rope is nearly buoyant with little catenary , it is very troublesome as an anchor rode.

When anchored between two islands in a narrow channel its common for wind and current conditions to be such that your anchor is behind the boat. When the anchor in behind you and the boat pulls tight on the anchor rode , your keel and rudder will grab the anchor rode. It is possible ,once the rode has grabbed the keel , that you will be forced beam too the current.

Very troublesome and almost impossible to escape the situation.

Since chain is so heavy it will always sag clear of the keel.

additionally , in difficult conditions , when retrieving your anchor you are motoring forward as you haul in the anchor in order to maintain head to wind and steerage. You almost certainly will run over your anchor rode. If its rope you are in trouble

 

Hi to all,

If some of you sailors are french fluent, a glance at a thread dedicated is of possible interest at: http://www.stw.fr/forumstw/quest_answers.cfm?quest_id=48188&st_row=1&rep_st_row=321&topic_id=22

Smooth anchoring to all.
Kindly.

Patrick

 

Use about 20% chain and 80% nylon or polyester. If you prefer, use some chain on both ends to help prevent fouling or abrasion on the boat. Do not use all chain with no snubber in extreme conditions.

 

Frankly I still stand by my conclusions from a thread a year or so ago here. That moving as much weight as possible into the anchor is the best way to generate additional holding power. In the theoretical this would mean using something like Dyneema as an anchor line, and shifting all the weight allocated to the anchor system into the anchor itself. When looking at the anchor weight allocations of most 30-40' crusing boats this would allow something like a 200lbs anchor and 20ish pounds of line.

There are a number of charts and tests done by various anchor manufacturers (therefore of suspect validity), that indicate that regardless of design modern SHHP anchors generate roughly 40:1 holding power:weight. While additional chain provided something like 1:1 holding power:weight.

In practice there are other reasons to use chain than just holding power, such as abrasion resistance, ease of use, and resale value. Given these using the lightest weight sutable chain, like Grade70, instead of the standby BBB would still allow a significantly larger anchor.

Finally we have the second primary anchor people tend to carry, which in my eyes is just a complete waste. Taking the total weight of these systems off the boat allows a massive increase in the size of the primary anchor. So much so that in many cases the primary anchor doesn't even need to be set, but can act as a reasonable dead weight anchor in benign conditions.

As an example, let's assume our primary anchor is a 60lbs plow of some type with 300' of 1/4" G70 chain, and the second anchor is a 60lb anything with 300' of G70. By eliminating the second anchor you could switch to a 330lbs primary anchor and retain the same weight on the bow. While this may be extreme, there isn't any reason to think it would negatively effect the boat, assuming an adequate windlass.

 

Actually the second anchor is critical. All boats need to be able to handle two anchors of the stem.

When the wind direction changes as the low center or front passes you need a second anchor set into the new wind.

Many common maneuvers require a second anchor..dont leave home without it.

Rope like dynema is to buoyant for anchor rode

 

Hi to all,

Here, in France, I must say G70 chain is quite exceptionnal quality, I mean rather hard to find. Standard products are typically in the range G35-40.

Greg, your opinion about the positive effect of an heavier anchor is well estimated through the calculation sheet provided here above.

To my mind, the utmost line - as described by "jonr" (please be kind to allow me using your firstname) - using chain then wire rope and finally chain is of great interest indeed.
Someone is commonly using that kind of equipment, in standard but not heavy conditions, with success ?

Kindly.

Patrick

 

What kind of winch would retrieve this wire chain hybrid ??

Sounds like a monster.

A typical heavy weather, things are looking bad scenario, has you...the helmsman...singlehandedly picking up the chain at 0200 while it is blowing 50 knts outside, struggling to keep the boat head to wind...so that you may evacuate the anchorage..put to sea or move someplace better.

The whole system must work flawlessly, from the helmsmans station.

Any complication and you will have bad day

This means 100 percent chain, and accurate chain counter , a chain roller that makes it impossible for the chain to jump out. and a chain storage box that can never overstack and block chain retrieval.

Dont even consider rope. Rope is for special events or a last chance effort to set your second anchor into extra deep water before you blow onto the rocks.


To handle rope you need a self tailing power winch. The intelligent set up is to use a power genoa winch near the helmsman. The rope must have a correct lead to the bow roller, the length of chain is equal to the distance from bow roller to winch. Chain will not go over a genoa winch. The chosen rope must fit into the genoa winch self tailer correctly.

A third anchor...typically a lightweight...HUGE danforth...is the breast anchor. This anchor is handled over the side , next to the mast , with a halyard trip line and is typically one hundred percent rope rode.

This breast anchor rode also double as your long line to take ashore.

In strong katibatic winds boats anchor, then turn the stern INTO to wind and back into the shoreline. A long rope is taken ashore and fastened to something.

The typical fastening is a three meter length of light chain with a chain monkeys fist or steel T bar or a micro anchor on the end. This chain tool is wedged between rocks in the way that mountain climbers wedge into crevices.

This stern rope also need a fair leed to the genoa winch

 

Hi Michael,

You are undoubtedly right, but, with respect, I must focus on the topic itself: "Anchoring in heavy conditions".

My aim is exactly to bring together opinions and - overall and preferably - calculations versus experiences - ideally measurments in typical situations - in relation with best designs for tuning anchor in the safest conditions permitted and taking into account each link from the ground to the sailing boat decking arrangements.
In absolute limits, of course, the responsible skipper should be in such a situation to set sail, but, if you agree, this is not my thread at first.

Nevertheless you're right once more concerning the mixed line here above described.
This is a point of particular interest after design aspects to discuss about: How to retrieve it onboard in heavy weather and secure conditions ?

Kindly.

Patrick

 

And dont confuse anchor design with a mooring design.

Mooring design is different.

An anchored boat is never unattended. It system must be human friendly

 

Even more importantly (in heavy conditions), it most not break or drag. A nylon snubber (parallel to the chain) isn't much added work.