Sea anchor - from the bow or stern?

Independence

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At a recent meeting of the Essex contingent of the Jester Challengers we discussed amongst other things the use of sea anchors.
Familiar with the for and against arguments ie, protection of rudder vs exposure of stern, I'd be interested in any first hand experience out there that supports 'one end vs the other'.
Regards to all.
Paul
 

CPD

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Hi Paul, if we are talking about wind having blown up a big sea, and nothing more obscure than that, then I dont understand why you would want to point the blint end at it all. not only is it blunt, but it also exposes the rudder. Surely it must be from the bow, thereby aiming the pointy end at it all, which is designed to hopefully, take it all. Sorry, i have no first hand experience, but thats what I would do !.
 

Ceirwan

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I'd never head of setting a sea anchor from the stern... It seems a little illogical, if you are presenting your stern to the seas the don't you want to be running with the wind and ways while trailing warps or something to slow down?
 

CPD

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Hi again Paul. It may be that confusion has crept in here, as I would happily tow a drogue from the stern to slow the boat down, but if the strategy was to sit to an anchor, then that would have to be from the bow. So thats my plan, small drogue from the stern to limit speed, larger parachute from the bow to act as an anchor.
 

ashanta

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PBO did a good article on this many years ago and view was the para anchor was attached to a line which was fixed at the bow and at a point further aft. This was so that the boat was not absolutely dead on to the waves but just slightly off.
The main problem they encountered was chaffing of the rope at the bow and where the Para anchor was attached to the controlling line.
 

CPD

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Agreed, so as to present yourself at a similar angle as you would be as if "hove to". Re the chaffing, any special secrets do you think to prevent it ?
 

Independence

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There are some yachtsmen out there who do / have used a sea anchor from the stern. The theory behind it is that even when lying to a big sea with a sea anchor the vessel will still experience some travel to stern.
I've yet to understand why this might be but I'm guessing it might be when the sea anchor is at the top of a wave and the vessel at the bottom of another one. The motion of both sea anchor and vessel out of synchronisation I'm guesing is the reason why some people say the vessel can still travel astern.
If the vessel is travelling astern then quite clearly the force of water acting against it could cause damage. If it was lying stern to then there would be less risk of damage.
At this stage I'm from the theory school of bow on but just wanted to explore any other ideas out there.
Regards
Paul
 

lumphammer

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Eric Hiscock in his book Cruising Under Sail also makes this point. His view is that with the sea anchor from the bows, the boat will always be ranging about and rarely lying head to wind, and also will still make sternway so putting extra stress on the rudder. His view is that the anchor should be streamed from the stern to be effective.

That's his view, fortunately I have never been in a situation where I have to try it out so I don't know from experience what is best.
 
G

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I can't think of anything worse than trying to keep the boat 'stationary-ish' when the weather starts to get really serious - unless you're in a heavy traffic zone of course.

The problem with deploying a good-sized sea anchor from the bow is that the boat will yaw wildy (just watch boats at anchor in a really bad blow ...). As much as 40 degrees each side of a parachute anchor have been recorded, when the forces on the string become truly enormous as the boat tends towards beam-on.
Restrained at the bow, a boat will always yaw, as a direct result of the unstable relationship between the centre of gravity and both the centre of pressure of the underwater surface, and the center of pressure of the air forces on topsides and rigging.

And, when a sea picks up your boat and pushed it hard backwards, the chances are that your rudder blade will smack hard over to one side and may well get damaged in the process.


The US CoastGuard http://www.seriesdrogue.com/coastguardreport/
investigated "The Use of Drogues To Improve The Safety of Sailing Yachts" (to prevent small sailing yachts capsizing in breaking seas), and their conclusions were:

i) In many and possibly most cases, a properly engineered drogue can prevent breaking wave capsizing.
ii) For fin keel sailing yachts the drogue/sea anchor should be
deployed from the stern, not the bow.
iii) A series type drogue provides significant advantages over a cone or parachute type drogue/sea anchor.

Personally, I favour open-weave basket-style drogues, made from car seat-belt webbing, and run out from a stern bridle. They're light, compact to stow, rot-proof, dirt cheap to make and so disposable should if you ever need to cut one free. They're also relatively easy to retrieve (- well, in comparison ...).

http://www.sea-anchors.com/goodoldboat.htm is a good read.

Colin

BTW - reinforced plastic hosepipe is mighty useful in avoiding chafe to any warp or mooring line. Not pretty, but effective.
 

Jacarah

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Tut Tut! Had you been on the main Jester Challenge site and browsed the recommended books, you would have seen the book by Lin and Larry Pardey, Storm Tactics Handbook. Purchased through the site, some money goes to the Jester Challenge.

The book is an excellent handbook on all of the above - and make a key point. A good drogue or even better, a parachute from the bow trips the waves and makes them break far ahead of the boat. If the boat is encouraged to lie about 40 degrees off the anchor, it won't sail about and will stay behind the slick made by the parachute. So they claim - but there is a lot of logic in it. Well worth a read. My copy now stays on the boat.

Incidentally I am new to the forum and have appreciated many of your ideas and thoughts so far. I singlehand around the NW of the UK- only managed about 450 nm non-stop but still managed to scare myself!
 
G

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[ QUOTE ]

A good drogue or even better, a parachute from the bow trips the waves and makes them break far ahead of the boat. If the boat is encouraged to lie about 40 degrees off the anchor, it won't sail about and will stay behind the slick made by the parachute.

[/ QUOTE ]

40 degrees off the anchor using a custom bow bridle will create truly enormous amounts of windage and drag - you'd need some hellishly strong gear to cope with those conditions - and some mighty strong attachment points.

What works for the Pardeys works for the Pardeys ... they sail a heavy full keel boat which is far more stable in rough weather than any light displacement fin keeler. Tactics may or may not transfer across, and the Pardeys are the first to agree that there are no such things as 'Silver Bullets' for survival at sea. http://www.sea-anchors.com/goodoldboat3.htm

There are plenty of good articles on the subject of sea-anchors/ drogues etc. :
http://www.multihullpages.com/Parachute_anchors.html
http://www.sea-anchors.com/index.htm


The bow vs. stern debate has been argued over for decades, so don't expect it to be settled on this particular thread ! <G>

Colin
 
G

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[ QUOTE ]
How is the webbing drogue constructed?

[/ QUOTE ]

See: http://www.hathaways.com/galerider/default.asp
for the commercial item.

To make a DIY one yourself, make a rigid s/s ring 2ft diameter (good for displacement of up to 2 tons), and use car seat-belt webbing to make a basket about 2ft deep. Glue the webbing together using thin epoxy - unless you happen to like sewing .... Recommend fixing a lead weight to the bottom of the basket.

They are so cheap to make, you could experiment with different weave densities without breaking the bank.

And - if you 'line' the basket with a small mesh net, the drogue can then double as a sub-thermocline beer cooler during the summer, without risking the bottles falling out.

Colin
 

CPD

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Does anyone know what are the recommendations regarding length of rope between the sea anchor and vessel ? Surely this will have an effect upon overall stability also.
 

beneteau_305_553

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I have tried both and found that trailing from the stern is far better than from the bow.
From the bow the boat does yaw badly, even enough sometimes to allow the boat to go broadside to the waves. Trailing from the stern with the rudder tied off on the centre line results in the boat just riding the waves as they come up from behind with no rolling and the anchor breaks up any crests so the cockpit stays dry.
I found it incredible the first time I tried it . The motion is easy and gentle.

Trying to stay bows to is so difficult as the boat will be travelling downwind (backwards) at about 1 Kt.

I use a Jewsons builders bag. Its terrific. Holds a ton of water and with 50 m of line stops the boat dead in its tracks. You may need more line if the waves have a long fetch.

If you leave a hole in the bag about 2 inch diameter the water drains out to make recovery easy.

Go out in at least a F6 and try it. It works for me but all boats are different.

Richard
 

beneteau_305_553

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Paul

I tried it first in my 1983 30 foot Beneteau first 305 and then in my Hunter 34 coming across the Atlantic.

I'll be down in the Stour this weekend at Wrabness if you want to meet up.
 
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