Saturday, 12 September 2015

How to avoid sleepless nights rolling at anchor.


September 12 - 2015

Our second anchorage on our current trip north to the Great Barrier Reef was at Double Island Point, a spot renowned for providing sleepless nights due to swell induced roll. While the point is reasonable high, the terrain behind it is much less so with the prevailing South Easterly winds flowing over it relatively unimpeded. Meanwhile the normal South East or Easterly swell swings around the point and enters the north west facing anchorage.

The prevailing South Easterly winds and swell twisting around Double Island Point made the anchorage the perfect place to test a different anchoring technique we had read of. Advice provided in pilot guides is to anchor close to the point itself which we did, but when we first dropped our 30kg (65lb) Sarca Ex-Cel we experienced the usual persistent roll from the swell rolling around the point. (Boat image not to scale)

In his highly respected pilot guide, "Cruising the Coral Coast", Alan Lucas describes the anchorage at Double Island Point as '…one of the most uncomfortable on the coast'. Despite this reputation, many, many cruisers to use it to await the right tide and suitable conditions to cross the nearby Wide Bay Bar for their passage through the Great Sandy Straight on the inside of Fraser Island. That was the situation we found ourselves in.

In our case conditions were relatively mild when arrived mid afternoon with under ten knots of South Easterly blowing. However there was still a persistent half metre or so swell rolling beam on into the anchorage. It was more than enough to guarantee an uncomfortable night. It was the perfect situation for us to try a different anchoring technique involving running an extended snubber line  that we had heard about. 

Even in near perfect weather, the swell at Double Island Point can roll your boat all day and night.

First we anchored normally in about 4 metres of water and set the anchor putting down our usual five times scope and reversed up to make sure the anchor was well set.  As soon as the boat hung to the wind we instantly began to roll. We had unlimited room around us so we dropped an extra ten metres of chain just to be sure.

Next, instead of running our snubber line over the anchor roller as per normal, we hooked a longer line into the anchor chain and ran it outside the safety lines and back to our genoa sheet winch at the cockpit. We then slowly let out additional anchor chain to effectively create a bridle. As we did this, the wind progressively blew the bow around towards the incoming swell. We stopped when we were facing directly into the swell and then rode gently over each wave with no roll. The snubber line and 30 metres of chain we'd originally put down ended up in a straight line to our well dug in anchor sitting almost ninety degrees to the boat. Through the afternoon we were easily able to fine tune the angle by easing or winching in the snubber line at the cockpit.

(Boat image not to scale)



Here Our Dreamtime faces directly into the incoming swell while the similar full keeled ketch in front hangs to the wind and rolls with every wave.
We ran our extended snubber around the staysail winch to clear the stanchion and toe rail then adjusted our angle to the swell by easing or bringing the line in on the genoa winch.

While the conditions were quite mild, we were very happy with the results we were able to achieve using this technique. In stark contrast to our comfortable ride, a very similar ketch to ours was anchored conventionally in front of us and continually rolled in the small swells. Its skipper had been below when we dropped anchor and didn't see our set up. It was amusing to watch him repeatedly come on deck, stare up at his swaying masts then look across to our boat rising and falling bow first gently over the waves. We could almost read his mind thinking, "I should have anchored over where they are."

A couple of times through the night the wind dropped out which did allow the bow to swing about a little giving us an occasional bit of roll but we never came around far enough to lay beam on. It was very nice to rise early the next morning well rested for our bar crossing on the last of the incoming tide.

---------------------------------------------------------------

UPDATE

Since that first test, we have used the technique many times with great success in a range of locations. One trap is if the current reverses or the wind changes taking the bow through the wind. Then the bridle ends up under the boat with the stern to the swell instead of the bow. You still don’t roll but the bridle could rub some anti-foul off. With a fin keel boat, we would recommend taking your snubber line to a midships cleat rather than a cockpit winch. This keeps the whole lot in front of keel and all but eliminates any chance of your line reaching the prop should the wind or current change.

Increased windage laying beam to the wind obviously adds to the load on your anchor and deck hardware so we only do this when the wind isn’t expected to top 15 knots. We also use plenty of chain and make sure the anchor is well set. We have unexpectedly experienced gusts up around 20 knots without a problem but if the wind persists at that strength we release the snubber and let the boat swing instantly bows to. We’re then no worse off than if we anchored conventionally in the first place.
Despite these limitations, we have enjoyed many blissful hours of sleep we would not have got without this a very simple  anchoring method. Give it a try and snooze on.

-----------------------------------------------------------------------------------------------------------------

We love to receive comments on our blog from readers. If you do leave a comment and you also have a blog, please leave a link as well. We'd like to click over for a visit and leave you a comment too.

To stay right up to date with what we’re up to  and see lots more photos check out and 'like' our Dreamtime Sail Facebook page at Dreamtime Sail

 https://www.facebook.com/DreamtimeSail/
If you have only recently discovered our blog and would like to read how it all started, or work through our previous adventures, click the link to go back to our first blog entry. Stuff it. Let's just go sailing anyway. 
We hope you enjoy reading the previous posts to catch up on our story.


15 comments:

  1. Great post Karen - definitely
    Going to try this!

    ReplyDelete
    Replies
    1. Glad you enjoyed it Sue. Let us know how it goes for you. Cheers.

      Delete
  2. Thanks for the informative photos !
    I do have a couple of questions- what do you think the upper wind limit would be for this technique, and did the boat shear about much as when normally at anchor ?
    Regards, Steve (DS43 owner....)

    ReplyDelete
  3. Hi Steve, We wish we had known of this technique when we had our 43DS, We would have loved to have tried it. She sailed about at anchor like a bitch when hooked in conventionally. We're sure this would have helped a lot. Not sure about an upper wind limit. That would depend on how good an anchor you have, the strength of the snubber line used and the cleat or winch you put it on. Because you can lay near beam onto the wind, there is a bit more load than being head to but it's worth it for the comfort of not rolling. We'd suggest you try it in light to moderate conditions first and go from there. We'd love to know how it goes for you. Overall we did love the Jeanneau by the way.

    ReplyDelete
  4. Great idea. Seems like you would get the same effect with bow and stern anchoring? Just curious if you tried that?

    ReplyDelete
    Replies
    1. It can be possibly to achieve the same result by deploying a kedge anchor but we like the simplicity of this set up. The stern anchor takes more set up in that you have to put a dinghy down to row or use your outboard to take the anchor out. Deciding the right spot to drop it to get your boat aligned into the swell can be difficult too. Then you have to get it to set properly. Cheers!

      Delete
  5. I did this in the Bahamas and got into trouble when the tide changed. Had to drop the snubber (fortunately it was tied to the chain with a rolling hitch) and tried to sleep the rest of the night on the sole.

    ReplyDelete
    Replies
    1. Yes you do have to be aware of changing currents.

      Delete
  6. I used to spend a lot of time at anchor in Porlamar (Margarita Island, Venezuela). The conditions there are exactly the same as you've described and I used to use a similar system with one more step. I made a "Y" with rope and attached the foot of the "Y" to my anchor chain. The other sides of the "Y" were attached fore and aft and then I played out plenty of chain. The reason for using rope fore and aft is because with chain on the bow and rope aft, as the wind increases or decreases the angle of the boat shifts due to the weight of the chain. With rope on both ends the boat remains at a more constant angle to the wind and requires less adjustment. svchama@yahoo.com

    ReplyDelete
    Replies
    1. Interesting. We might give that a try. Thanks Jeffrey.

      Delete
  7. Yes it works great, I have bee doing this for a few years and have used it in pretty strong winds on my mooring, when on board, also by extending th bridles. I regularly get calls to say there is something wrong with my boat!

    ReplyDelete
    Replies
    1. People do look at you and scratch their heads a lot.

      Delete
  8. We have tried this a few times with success and once when the wind and tide turned to wrap the warp and chain around the keel. Worth keeping an eye on if you use this technique.

    ReplyDelete
    Replies
    1. Yes Hans, you do have to be aware of changing conditions. On a fin keel boat running your snubber to a mid ships cleat instead of a cockpit winch keeps everything forward of the keel and should prevent a wrap. Cheers!

      Delete
  9. Just another vote for a pair of flopper stoppers. Especially where winds are constantly rotating.

    ReplyDelete

We love to read your comments regarding our blog, what you enjoyed and what you might like to see more of. Please leave us your thoughts.