Sea anchors - are they secretly a bit rubbish or wot?

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Yep, obviously this folows from the Richard Woods post. He had one, laid it out but the boat yawed 40 degrees and felt dnagerously side-on to big waves.

Anyway, tho i have far less exp of nasty stuff that RW, I bort one for med-uk-med tripthru biscay, and since no actual v v bad wetaher in biscay i tried it on big powerboat in 10-20 knots in the med, and although the line was tight and correct length about 10x boat length, the boats yawed about exactly as RW described with his cat.

At the time i though well maybe if there was really massive wind it wd hold nicely into the wind. Pity, cos i though it would allow us to sit in flat water miles out at sea and not fall beam-to the wind/waves. So i don't carry it any more althop obv i had planned to do so for bigger trips.

Does anyone have better para anchor exp? Mine was proper thing like (it seems) RW's. Perhaps they don't work if no keel as on his cat and our powerboat? I rang the bloke and he said you sometimes need a bit of sail to flatten it into the weind which er ain't an option on a powerboat and didn't sound as tho rw felt like putting any sail up at all!
 
Not tried one in anger, but plan would be stream warps from stern (sailing boat) up to a point where I felt we were moving too fast, then if possible stream para anchor.

I wonder about your situation whether the para anchor would have come into its own at ' survival' windspeeds, you'd be looking to have something holding your bow to the wind...
 
Various advise has been voiced in MN / RN circles about them .... biggest discussion was the use of oil in a bag on the rode to quell water ahead of the "lifeboat".

They have been carried for donkeys years in ships lifeboats and rafts .... used many a time as well.

I would suggest - based on what I was told in MN to lay out long warps and anything else that can pull the stern and put weight onto the anchor rode ... thereby getting the sea-anchor to hold water and resist movement better .. in so doing pulling the bow to wind.
The act of putting up a small riding sail is not a bad idea and well worth it if you can .... likewise increase aft windage if nop sail ... reducing it fwd if possible.
 
fair enuf.

Terminaolgy wise we are at x-purposes: anything you can tow and slow you down whilst still going downwind is called a drogue.

Whereas a "parchute anchor" aka "sea anchor" cannot be towed cos it is a giant parchute (ors 35 feet across i think) and hence is always launched off the bows.

They advertise these as a mooring buoy and an opportunity to get some rest. This was clearly an issue for RW who was ok with any of the indivudal event - but not when it went on and on and on and on, and hee called the mayday when the prospect was for it to go on and on perhaps when they'd be asleep or in een worse condition.

Thinking about it, praps it wd be better to have engines on tickover, running astern to keep tension on the parchute anchor effcetively gently and constantly "dragging" against the parchute anchor and staying bows to waves. Maybe. Then still as you say runing downwind but with stongest part of boat facing the waves. Mind you, RW's sea anchor busted without any such puling so that probaly wdn't have worked for him...
 
I have been trying to make my mind up about this for some time. Actually have two parachute anchors which came with the boat but have not deployed them yet. I don't like the idea of trying to stand up to an open water breaking wave in any sort of weather.

There are a number of sites that discus the use of para anchors and drogues, this is just one of them.
http://seriesdrogue.com/vs/

The concensus seems to be para anchor to stop drift providing none breaking seas, otherwise drogue to stop surfing in a wave break.

I have experience of running off under warps and storm jib in F9 conditions off Fair Isle in an 8 metre BobCat - a catamaran. (Way back in 1970's). We were hit by three large breaking waves in quick succession. First filled cockpit, Second filled cockpit and left us broadside on. Not sure what happened with third but we lost both rudders and various other bits around the stern. Boat then found her own equilibrium and looked after us until things eased a few hours later.

Fortunately, our storm only lasted 12 hours or so. Got out of immediate danger during eye of depression with favourable tide in Sumburgh Roost, sails and outboard engine for steering - then got a tow.

Interestingly, we found the contents of all lockers piled up at the aft end of the lockers - indicating the accelerations we experienced were greater than gravity when bows down on the face of a wave. No option to leave the boat as flares were not seen due to low cloudbase and no VHF etc in those days.

My feeling is to try to ride the punches so am seriously considering a series drogue as it is unlikely to go totally slack and should keep the boat stern into a breaking wave. Do a web search for series drogue for more info.
 
Have never managed to get one to set really properly, but you certainly never will on a single line. On a cat you need a bridle from each hull and a mono needs to have something similar with a rope from the stern as well as the bow to stop the boat shearing about from side to side. Only minimal tension in the stern rope tho' You don't want to be broadside on...... Also the length of rode and the pitch of waves is a consideration to get both to go up and doon together.....Or so they say!
Personally I don't want something this bleedin difficult when I am already knackered and shitting myself. Series drogues are great and not critical. I know you can just chuck em over an' they work. Getting the bu**ers back on board again however......now there's yer problem..... Tripping lines? Don't talk to me about tripping lines......... Last time I tried one of them I knitted something very similar to a parachute shaped jumper....... Naaa! Too much trouble...... Upturned buckets mate, thats what you want.... Or tyres, or ....anything but not a f***ing great parachute...
 
That sounds like it was fun! Ever think what would happen trying to set a sea anchor off the bows of a bobcat in a F9? I wouldn't want to go out there to play with bits of string meself! Naaa.... chuck the drogue over the stern an go an make yerself a mug o' cocoa.... Much safer. First rule of survival. In the boat is safer than in the water..... All this bllocks about tuning to the wavelength and frequency of the sea was written in someones lounge in front of the fire....
 
aprt from the anchor failing (and this might have been due to its age eg stitching coming apart), the failure of the warps seems quite common in other peoples experiences. The constant expansion and contraction of nylon, and nylon is the recomended warp to use so presume RW was using it, causes it to fail. It could be the heat generated in the rope causes the polymer to degrade and the failure occurs above water and close to the boat.

if the storm lasts long enough, it appears the warps will fail. The other thing is that one claim made for these anchors is that, once streamed, the motion of the boat settles down allowing the crew to get some rest but this wasn't so with RW. So, yes, a bit crap?
 
After reading your post it occurred to me (for the first time) that a boat could "sail around" a sea anchor in the same way it "sails around" a real anchor. If a boat is susceptible to this phenomenon while anchored, perhaps deploying a sea anchor might not be the wisest approach during heavy weather.

The problem is that this is caused by the boat's design - in modern terms, usually high freeboard forward, shallow forefoot, fin keel and rudder. Although setting a riding sail well aft might help, I am not sure it would entirely eliminate the problem.

I have read (perhaps on these forums) that someone has had success in eliminating the "sailing around" problem by anchoring by the stern. Could it work for a sea anchor as well? Assuming the waves are not breaking, why not?
 
Thats what a bridle is supposed to prevent actually, but the other thing peeps miss is that anchored into the wind you take the whole force of it. Going downwind you reduce the force of it. Have you never been beating into a good breeze crashing about and then turned downwind and thought "what was all the fuss about"? That's the difference between a sea anchor streamed off the bow or stern and a drogue. IMHO if you have enough sea room, you actually want to go downwind! If you go too fast though its dangerous and you can crash into the valleys between the waves burying your bow in the next big green lump. If you can keep her going downwind at a slight angle to the waves at 4-6 knots its the best result you can achieve and loads more comfortable than sitting still....
 
No experience of sea anchors or drogues, but..........

If you drop all sail and simply lie ahull, every boat that I have tried it on comes to lie beam-on to the wind (within 10 deg. or so, anyway). I have always assumed that this was the effect of the underwater configuration of the boat. Think of it as a flat plate. If the plate moves forward at an angle to the water then it will generate lift; more near the leading edge than near the trailing edge. The above water configuration is much less like an aerofoil, and the wind forces will tend to be more equally spread. The result is that the combination of the wind force and the water force will tend to turn the boat toward the wind. However, once the boat comes beyond the beam-on position the effect of the wind will be to push the boat astern; the centre of pressure on the keel will now move aft and the boat's stern will move towards the wind. In the end, after oscillating a bit, she will lie beam-on.

The effect of putting a drogue on the bow is to move the effective line of the water force still further forward, bringing the bow in to the wind. But the boat doesn't completely stop in the water; she will be slowly moving backwards. It's as if she were on a mooring in a strong wind against tide situation; she's trying to lie to the wind but the tide is coming from aft forward. Anyone who's tried it will know that it's a very unstable situation, and that the boat swings quite unpredictably.

With a sea anchor, though, it's not the water that is moving, it's the mooring. I reckon that it is that backward movement of the boat that gives the keel forces that cause the boat to swing, and that if you want to stop it then you must reduce the boat's speed by using a very big anchor. A small parachute or drogue over the bow may not give a sufficient reduction in the boat speed.

After the 1979 Fastnet Race a lot of work was done to establish the correct use of a drogue on a liferaft. Maybe one of the Universities could do equivalent work (both theoretical and practical) on drogues for boats?
 
I've just bought a 9' para-anchor for the Rival. They say that big ones are really for fishermen who lie to whilst hooking things. The smaller ones are for emergency use apparently. They sent a good video demonstrating useage and certainly they seem to be used either one line off the bow or with a bridle to set the boat at an angle to the wind/sea. I don't see how you could sail round one if you lie a-hull to it. The other point is that if you are drifting slowly back instead of running at some speed then the weather should clear past you faster should it knot?
 
Re: I\'ve never been a fan

of sea anchors or any other sort of passive tactic in heavy weather. I don't do the lottery either. Once you go passive it's going to be a lottery whether you survive and going active again is going to be much more difficult.

Anyway I'm not going to die skulking in the cabin when I could go out blasting down waves.
 
Hear!Hear! Have experienced really bad weather on 2 occasions.1.In F9 Treguier - Salcombe on GibSea 42 (Out of date French Weather Forecast) the skipper put 3 reefs in the main and motored into it on what I think could best be described as initially a close reach arrived Salcombe 27 hrs or so later tired with no damage to boat/crew.In same storm 9000 tonne merchant vessel lost.2.Bay of Biscay bilge keel Westerly Conway in winds in excess of 60 knots (off the clock after that - but it was a lovely day when we set out) ran before it with minute amount of r/reefed foresail out (One experienced helmsman froze on the wheel and member of crew on fishing boat in area lost overboard).On both occasions I was just crewing but it never occurred to me that what we needed was a 35 foot diameter parachute to swing on.Warps/chain/oil soaked sleeping bag out the back maybe.I think he who runs away (slowish like) lives to fight another day.
 
Re: I\'ve never been a fan

[ QUOTE ]
Anyway I'm not going to die skulking in the cabin when I could go out blasting down waves.

[/ QUOTE ]

I'll take the helm whilst you grab a sandwich. Don't be long
 
Now there seems to be a type or design of Sea Anchor that I have missed here ...

A sea anchor - lifeboat style is :

about 1.5m long, with a mouth about 1/2 to 3/4m wide ... tapering down to a hole of about 15 - 20 cms. Made of serious canvas with a bamboo, wood or metal hoop to hold mouth open ... warp normally a heavy 3 strand natural fibre warp.

I have not seen a Sea anchor like a parachute ??? Are you sure someone hasn't mixed up names and terms ????

I shall cont. to regard a Sea Anchor as the type I describe having actually made them for lifeboats as cadet etc.

Mmmmmmmmm
 
The MN you're familiar with is a drogue to arrest lifeboat drift, bit like the ones fitted to liferafts. You wouldn't want to try to moor to it but it's useful streamed astern to slow down, give steerage etc

Parachutes are deployed from the sharp end and stop the boat in the water, facing the weather
 
As well as the two Para anchors mentioned earlier I also carry two standard liferaft drogues, but these are only for slowing drift if I have to wait for the tide to turn before entering harbour. One works fine off the quarter in a fresh breeze bringing the cat down to 1 kn or so, but will rig the two in series to increase drag for next season.
 
There are many types. The types you mention are derived from drogues but bigger. There are others on the market that are exactly like a parachute with a hole in the middle. The latter type are a menace IMHO and it sounds like this was what Richard Woods had recently which broke. The former will work as either an anchor or drogue with smaller sizes being good drogues. No experience with larger ones but for reasons I have already stated wouldn't want one anyway.
 
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