Parachute Anchors?

[blackdaisies]

Does anyone have a preference for sea anchors/bag anchors? I've read they are not as good as what? Because they don't sell any other type. I've seen one made from layers of square metal shapes stacked on a metal poll in succession from bigger at bottom to smallest at top attacked to a chain.


A group of small bags of rocks on short rope around the edges? I'm talking about a 15 foot boat or catamaran, no engine, just sail made from plywood maybe for example.

I would think it would be in the best interest to keep more than one type of anchor. I like the mushroom types from what I've read, but the are only good for shallow muddy waters. The ones with the hooks are scary and I think they would sink more boats than keep them save in rough stormy waters getting the ends stuck on something.


I think a few bags/boxes/ metal ball shapes of rocks on a short rope would be better and more level than one anchor at one end.

Does anyone have any complaints about parachute anchors? I have read nothing good so far. Where do you buy other types of sea anchors?

[Stumble]

If you are talking about sea anchors, they are designed to slow down a boat while sailing in heavy sea states to keep the boat from sliding down the back side of one wave and accelerating into the front of the next. For this there are a lot of things that will work, but the normal design is a cone shaped piece of fabric dragged open end towards the boat, with a line run to the sharp end that inverts the anchor when you try to pull it out of the water.

Honestly a 15' cat probably doesn't need this type of anchor since I doubt you will be caught out in the type of conditions where they would be needed.

Now for a normal anchor, there are a LOT of different designs out there, all of which have their own best type of sea bottom they are best in. So you really need to identify the bottom before you select the anchor. However there is NO bottom where a bag of rocks is going to be the best type of anchor to carry on board. These types of 'anchors' rely on just dead weight and provide almost no design hold, and need enormous weight relative to the size of the boat to provide a secure anchorage.

My recommendation for a lunch anchor would be a small danforth with six feet of chain and 4-5 times the expected depth of the water as rode. Danforths provide a reasonable amount of holding power relative to their weight though they can be awkward to stow. The other option would be some type of plow anchor that are easier to carry, but don't hold as well in all bottom types.

However on a 15' cat I doubt you will need an anchor very often, and for the amount of weight they would be it probably just wouldn't be worth it.

[Alan M.]

Originally Posted by Stumble

If you are talking about sea anchors, they are designed to slow down a boat while sailing in heavy sea states to keep the boat from sliding down the back side of one wave and accelerating into the front of the next. For this there are a lot of things that will work, but the normal design is a cone shaped piece of fabric dragged open end towards the boat, with a line run to the sharp end that inverts the anchor when you try to pull it out of the water.

What you've described is usually called a drogue. A sea anchor is a much larger, purpose built parachute, usually deployed off the bows of a boat, to hold the bows into the waves, and to (almost) stop it from drifting downwind.

[Stumble]

Ouch I hate when I get those confused... Time to reread Chapman's again...


Either way though, neither would likely be gear I would consider carrying abord a 15' Cat.

[blackdaisies]

They are used in bad weather and cheap to carry being they are only bags. But in case I'm in a deep lake area, ocean area where there is no bottom, what type would I use? A 15 foot cat will likely drift a long way being it is light, so keeping it in one spot even just while fishing or swimming is what I'm talking about.

I don't see a reason to drop a 50 foot anchor to secure a 15 foot boat. I would be nice to stop it from drifting. In bad weather the sea anchors are not bragged about by their performance. That is why I wanted another option, maybe the metal one with square shapes set apart with the big square at the bottom up to littler square at the top.

You are talking about drogues? For trolling, but that is not what I want. They can be used the same almost, but I guess one is bigger than the other.

[Stumble]

So you want to keep the boat in one spot without ground tackle? I can't think of anything that would do that... I guess a large drough would minimize the drift of the boat due to wind, but wouldn't do anything to prevent the boat from drifting on a current.

[blackdaisies]

How do people in the middle of the ocean keep their boats from slipping away? I would be terrified using a hook anchor. They would get hooked on something and the tide would roll in, sink your boat! But maybe they don't work that way. I guess slow drifting is better than drifting.

[Stumble]

In over 10,000 miles of ocean sailing I can't remember ever wanting to be stopped in the middle of the ocean. Though the doldrums definatly make me NOT want to be dead stopped. The reality is that in deep water the only way to be dead stopped would be computerized position keepers that are used in very large boats in place of or along with an anchor. These work by gathering GPS signals from at least two antennas on board and using the onboard engines and bow thrusters to keep the two signals in the same GPS position.

For small boats there just isn't a realistic option, other than an anchor to keep you in the same position. But limiting drift will allow you to make sure the boat doesn't drift any faster than the water current.

[rwatson]

50 ft of rope isnt a lot BD. Its only three time the length of your boat, and double that length will fit in a small canvas bag on a small cat.
Compared to the hassle of other types of drift preventers, its your cheapest , smallest and most reliable method.

[Stumble]

And remember the amount of line you put out while anchoring has nothing to do with the boat, it has to do with the depth of the water. The deeper the water the more line. For a quick lunch break maybe 3:1 but for a longer stay or bad weather 10:1 is normally considered adequate. That means if you are anchoring in 10 foot of water, you need at least 30 foot of rhode. So fifty foot of line is only good for between 17 and 5 feet depending on how secure you want the anchorage.

This is why many large boats may carry as much as 600' of Rhode, so they can safely anchor even in deeper water.

[blackdaisies]

That's good to know. 150 feet of rope is what I'll have or even 200 couldn't hurt, but what did they used to do in bad weather besides use a sea anchor?

Do you think they can be used on a boat with no ballast for sailing? What about can they do what a daggerboard or centerboard does?

There must have been other options available for ocean voyages other than parachute types of anchors. If you fish on the ocean, you will not want to drift. Or swimming to bath would be nice and not have your boat drift away.

I guess the parachute can be a good emergency tool for extra ballast.

[Ike]

For open ocean, if they could not or did not want to use a sea anchor or drogue, they hove to. Hove to or heave to, does not stop you from drifting but considerably slows your drift and allows the boat to be relatively stable. It is a method of reducing sail and flattening the sail and lashing the rudder amidships until the boat pretty much balances itself to the wind and seas. Ideally you can then leave the helm, go below and get some rest.

"Heave To - to stop a boat and maintain position (with some leeway) by balancing rudder and sail to prevent forward movement, a boat stopped this way is "hove to"" see also http://www.google.com/search?hl=en&r...ition&ct=title

Also the USCG did a study on sea anchors and drogues back in the 80's look here. http://www.seriesdrogue.com/coastguardreport/

[blackdaisies]

3.3.4 Conclusions
Back Forward Index

After observing the various drogues in the water channel, it was apparent that a cone or a small parachute drogue will collapse when the towline goes slack, as will occur each time the boat passes through the trough of a large storm wave. This behaviour results from the fact that the mass of water in the wake behind the drogue continues to move forward after the towline force has dropped to zero. This wake can collapse and even tumble the drogue.

There is a long history of drogue failures under storm conditions. It is probable that the alternative filling and collapsing is a major cause of these failures. In a single storm, a drogue can be subjected to as many as 10,000 cycles. The very large parachute drogue and series drogue do not behave in this manner; however, the small conical elements of the series drogue are subjected to some cyclic motions. A section of the full-scale series drogue was subjected to a fatigue test which will be discussed in a later section.

This is what complaints of the droques and parachute anchors I was reading about and this explains why it does not always work. Hove to and heave to are probably recommended or required like turning your wheel to the curb is on a hill. Buth this is exactly what I was asking about. Thank you for the information and I'll read up on hove and heave to be more familiar with it.

Other tests on the page said it did well in the real tests, but these people I read about complained about them in real storms, and heaved to like you said.

[blackdaisies]

http://en.wikipedia.org/wiki/Heaving_to

Strategies for small vessels in bad weather

There are at least four different methods of surviving the bad weather at sea, "lying ahull", "lying to a sea anchor", "heaving to under reduced sail" and "heaving to sailing off the wind".

[edit] Lying ahull

Lying ahull is accomplished by dropping all sails, fixing the helm to a set position with the tiller to leeward (or the wheel to windward) to prevent the bow of the boat from turning too far downwind, and allowing the boat to drift. This method is controversial in heavy weather, as the boat is at the mercy of the storm, and can end up "beam to" the seas (side facing the waves).

[edit] Lying to a sea anchor

Using a sea anchor or para-anchor helps keep the boat pointed in one direction, slowing the boat's progress against the storm, and is called "lying to a sea anchor."

[edit] Heaving to under reduced sail

Heaving to under reduced sail is often employed by recreational sailors on small boats, as well as cruisers on larger boats. The skipper keeps the jib cleated but starts to tack. As the bow of the boat turns into the wind, the jib will be on the "wrong side" of the boat and be "back winded". As the boat stalls, the skipper pushes the tiller to leeward (or turns the wheel windward), and lashes it down. Some sailors prefer to ease the main sheet until the main sail stops luffing, while others prefer to bring the mainsail to mid-point on the traveler and cleat it there. The boat will tend to move forward a bit, while slipping leeward a bit. In many boats, the amount of slippage leeway is twice that of forward motion, so care must be taken to allow enough seaway.

[edit] Heaving to sailing off the wind

When sailing on a beam reach, broad reach or run it is advantageous to heave-to without coming up to a close hauled point of sail and tacking over. Heaving-to downwind can be accomplished by bearing away from the wind until the headsail is blanketed by the mainsail. When the headsail collapses onto the foredeck it can be hauled tight to the opposite side of the boat. Once the headsail is secure, the boat is slowly rounded up into the wind. As it rounds up the boat will stall and come to a stop in the heave-to position. The advantages of this maneuver are two-fold. First, it relieves the crew of the effort in getting to the close hauled point of sail before heaving to. Secondly, the boat remains on the same tack and does not have to tack back to continue on its course.

Here's what I found on being at sea in deep waters during a storm for what to do. Thanks again for the url. It was exactly what I was asking about.

[Brent Swain]

I once bought a cargo chute for a sea anchor. It was shiny like nylon so I assumed it was nylon. It only lasted an hour. It was cotton.
Check any parachute and it's shroud ends with a match . Nylon melts, cotton chars.
Brent