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Old 13-02-2006, 20:35   #1
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Para-anchor and coastal boating

I have the opportunity to purchase a "never been used" para-anchor (parachute) and have been in a quandary over whether to get it or not.

I was reading in some source (don't remember where) that in coastal cruising you don't really need a parachute since ports are so easily accessible. In a way this makes sense, but I'm wondering if it makes sense like - "if the boat goes down, I can always use the dingy (my thinking being if the seas are that bad, just how long will the dingy last) - kind of thinking.

The majority of my sailing will most likely be within thirty miles of "home." I purchased a "sea brake" (a drogue) but my understanding is that many have found drogues lacking, keeping the bow point to high into the waves.

With my understanding of using a parachute from the Pardy's Storm Tactics video, having the boat heaved to, while deploying a parachute at an angle, obtained by using a second line, seems to make sense; though I've never tried it.

So what's your position of coastal cruising and parachutes?
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Old 14-02-2006, 04:21   #2
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Rsn48,while not being the person too give you the info that you need,I have learnt enough from this here forum to give this advice at the least!The old sea brake,regardless of what type or brand name,is an essential item to have aboard to say the least.You seem to understand what it's used for but it sounds to me like you have never needed to use one.I have no doubt that some of the old/young salts on this forum will chip in and give you heaps of advice,mainly to the fact that which type of "Brake" you use will become a preferance to yourself,maybe,after trial and error.But do listen to what they have to say before you rush out to buy it.But one thing Im pretty sure of is If ya loose ya boat in a situation like what you were imagining,I doubt a dingy would be the best place to be either!But then I've read a lot of stories that will make that comment sound like crap.CaptK bound to have a lot of insite on this and if not he will lead you to a safer understanding in one way or the other.Mudnut
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Old 14-02-2006, 04:54   #3
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Hi rsn48.
It's important for everyone to be on the same wavelength in the difference between a sea anchor (parachute) and a drogue.
A sea anchor is designed to hold your bow into the waves and halt or reduce movement through the water. It places a lot of strain on it's anchor points which are often only built for lying to an anchor in conditions far less extreme than the conditions you are likely to be using it in. It also has the potential to damage your steering gear with backwards movement, slamming down off wave crests etc. Its main advantage is that it exposes the part of the boat (the bow) that is designed to meet the seas.
A drogue is designed to be trailed from the stern and has 2 purposes. One is to slow down forward movement and the other is to stabilise the vessel direction at right angles to the seas to prevent broaching. It has the disadvantage of exposing the stern and cockpit to the seas.
A drogue will help you maintain control of your vessel, whilst a sea anchor will immobilise your vessel. A drogue would not be appropriate on a lee shore but would likely be the best option in large seas with lots of sea room. A sea anchor has the ability to be adjusted using a bridle to give you a more comfortable ride and may be more appropriate in less severe conditions.
IMHO, once you are getting 30 miles from home (depending on local variances in expected sea and wind conditions and the ability to work harbour entrances in any weather) then you shouild definitely be carrying one or both of these systems.
If you have the chance to buy a sea anchor at a reasonable price then I would go for it. A drogue can easilt be jury rigged using warps and tyres etc.
There are a few other threads on here extolling the virtues of series drogues amongst others that are well worth the read.
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Old 14-02-2006, 11:30   #4
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I agree totaly with Pete, but if I may also add a slightly different angle to the view. I view a sea anchor much in the same way as say a liferaft. You use it when all other avenues are exhausted. My first avenue would be a weather watch and where do I go and can I get there in front of the weather. To me, 30miles would be ruffly 6-12hrs to shelter for most situations and well within the forecast predictions. I think if you are outside of a 12hr safety slot, then having a sea anchor is probably a good safety aspect.
I could add more, but I am then just parrating what I have read. I will leave that to the experts that have done.
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Old 14-02-2006, 11:56   #5
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Sea anchor

Why do you have to connect a sea anchor to the pointy end. Same thing for throwing the anchor over the side. There is not much room up there and it goes up and down a lot. Why not chuck stuff off the blunt end. Why not use the sea anchor off the blunt end. You can have various sizes. That is allowed. A small one will slow the boat down, good for fishing, and that is likely why they were invented. If you want to slow down some more put another one out. We need to be able to vary the speed, just like the wind and the waves do. I will not let my boat go backwards through the water. Don't care what the others do. It is pointy end first for me, with varying degrees of brakes. You can attach them in the middle of the boat and that will allow the blunt end to go up and down. These things are fairly easy to make and can be scaled up and down in size. Some may want to differentiate but brakes are brakes, drogues / anchors, just come in different sizes so will apply more or less braking pressure.
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Old 14-02-2006, 12:17   #6
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I'm no expert! But I do know that differant size para's are for differant sizes of boats. As well, the boat should be rigged to take a para. Is this para the right size?

For my vessel it is recommended that I have chain plates installed in the tramsom so the lines will run over the deck and forward to the para. Will your bow gear take the stress?

As well, over sized lines and chaff prevention are a must.

The reason for not using it off the blunt end. is your rudder. Do you want to keep it?

There was an artical just recently about a Cat builder that had to abandon his Cat after use of his para which got shreaded and failed. I don't remember where I seen the artical but it is an eye opener.

My $.02
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Old 14-02-2006, 12:29   #7
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Rudder

The strain on a rudder going backwards at two knots would be a lot greater than going forward at two knots. Going backwards could possibly break the rudder and or fittings. Going forward does not usually break rudders. Where is the danger to the rudder from dragging a drogue or sea annchor off the blunt end ?
Obviously the sea anchor should be sized for the boat, just like the sails. What is wrong with carrying various sizes for various conditions. Chuck a small one out so you can have a nap, a larger one for more serious stuff.
I do not think putting a boat partially beam on to large waves is a good idea. I would prefer to be square on, and if square on I would like the boat to be going the propper way. One of the boats did just that in the 98 Hobart race.
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Old 14-02-2006, 13:13   #8
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Re: Rudder

Quote:
BC Mike C once whispered in the wind:
Where is the danger to the rudder from dragging a drogue or sea annchor off the blunt end ?
Michael
A drogue Yes! A sea anchor No! Do you really think every wave coming up under the transom is going to be only 2 knots. A drogue is to slow you down and to keep from surfing tall wave, not make you go backwards.

Para's are shaped like a parachute, designed to hold back as much as possible.

Drogue's are shaped like a funnel, designd to slow down but has a metering hole to allow a lower shock asorbsion. have you ever seen a wind sock at the airport. No matter how fast the wind blows the sock maintains. Now put up a parachute. It'll get ripped apart or tear out it's mounting.

Carrying all these different sized para's, the boat would become a store house...................._/)
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Old 14-02-2006, 13:45   #9
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2 knots

I am having trouble following your points. I did not say anything about waves going under the boat at two knots. I am quite familiar with wave speeds and theory.
Some folks advocate having the pointy end to the waves. I am saying I would prefer the blunt end to the waves. Do I also have to say where the lines should be located to achieve this? I thought the idea of attaching them midships ( with the boat going forward ) was a worthwhile idea. It was proposed by another Sydney Hobart sailor.
The waves are going 12 to 18 miles per hour depending on size.The boat might have been going 5 to 12 knots depending on the boat. The drogue, or a suitably sized sea anchor will slow the boat down, depending on the size of the sea anchor / drogue, the size and speed of the waves, the speed of the wind and the amount of sail up.
The desired speed of the boat is set by the skipper for the conditions. That may be 2 to seven knots depending on the boat if it is going forward. It may be zero to two, or possibly 3 or four if the boat is going backwards.
It is my opinion that there is more strain on the rudder when the boat is being pushed backwards.
I am familiar with the design and construction of sea anchors. I build my own. They lay flat in the boat and take up next to zero room. If you only have one large unit it may slow the boat too much. I would take more than one of varying sizes. Others can do what they want.
A sea anchor will slow the boat or almost stop the boat depending on its size and the conditions. I still can not figure out how they would damage the rudder, unless the lines got tangled around it.
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Old 14-02-2006, 14:36   #10
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Thank you mudnut, for your compliment?

But I'm learning about these systems too?
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Old 14-02-2006, 23:43   #11
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I guess the whole "hanging a parachute off the stern" thing is very dependant on hull type. I had forgotten that I used to skipper a double ender fishing boat with the wheelhouse forard so used to stream the chute off the net roller on the stern. Made for a very easy recovery and we used the chute in anything over 10 knots of wind if we wanted to park in the same place for the night. With a square transom and aft cockpit I would feel very exposed though.
I have worked on 150 metere boats with a parachute 90 metres in diameter
On that vessel I witnessed the boat doing 1 knot into a 40 knot breeze due to the current running in the opposite direction. Biggest problem was the wind dying off and the boat drifting over the chute, blocking off all the sea water intakes and overheating the engines. 10 crew had to man handle the bugger away from the hull.
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Old 15-02-2006, 11:38   #12
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size of parachute

I phoned one of the parachute companies and the formula I was given for the size of the chute is a diameter of the para one third the length of your boat. I have a 27 Catalina so I should be looking at a parachute 9 feet in diameter.

The deployment of the chute that makes the most sense to me is as illustrated in the Pardey's video "Storm Tactics" which is a bridle off the bow and amidships to control the angle of the boat in the water.
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Old 15-02-2006, 11:51   #13
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Size

That is really big for a 27 foot boat, but may indeed be the size required. I would prefer to have two at 4 1/2 feet. The ones I have now are about three feet. The Pardey's system for adjusting the angle makes sense to me. They have a long keel boat which will function a lot differently than your boat. There are many functions at work. I would do plenty of testing first. They have only tried it once and fairly recently. Your results with your boat may be a lot different. The Pardey's boat is a lot heavier for the length than yours or mine. It is heavier in total weight than the 10 foot bigger boat I am considering.
One other point I find confusing and not very helpful, is a lot of this is based on theory and may not in fact work. I know we have to have a plan to start with.
When I am at the boat show and ask a question about a paint, most times the rep will look at the can for instructions.
What I want for an answer is practical experience. I want them to say something like: " The last time I used this product in those conditions it did this " When I sold boats I tested every one of them, and I knew how the different products worked. I have owned and used a sea anchor ( small ) for fishing for a long time.
Michael
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Old 16-02-2006, 09:52   #14
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Parachute sizing chart

Here is a chart I found on the internet for sizing a parachute, you will notice that my suggested 9 feet for a 27 foot boat, according to the following chart is too small:


Specifications & Sizing Guidelines

Sizing is first based on length overall with weight, keel configuration and windage taken into account next. Note that generally the greater windage of power boats equals the greater draft (wetted surface) of sailing craft, hence the same size Sea Anchor. When in doubt go to the larger size. GENERAL RECOMMENDATIONS are as follows:

Boat LOA
Displacement Sea Anchor Size Packed Dimensions Weight
Under 20 ft. Under 4,000 lbs. 6 Foot 6" Dia. X 7" Tall 6 lbs.
Under 25 ft. Under 8,000 lbs 9 Foot 6" Dia. X 9" Tall 9 lbs.
25 to 33 ft. Under 12,000 lbs. 12 Foot 8" Dia. X 12" Tall 12 lbs.
30 to 40 ft. Under 25,000 lbs. 15 Foot 10" Dia X 15" Tall 20 lbs.
35 to 48 ft. Under 40,000 lbs. 18 Foot 12" Dia X 17" Tall 25 lbs.
40 to 90 ft. Under 95,000 lbs. 24 Foot 13" Dia. X 19" Tall 35 lbs.
70 to 120 ft. Under 200,000 lbs. 32 Foot 16" Dia. X 25" Tall 55 lbs.
120 to 150 ft. Under 300,000 lbs. 40 Foot 18" Dia. X 30" Tall 110 lbs.
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Old 16-02-2006, 10:56   #15
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Sizing

I find the sizing a bit confusing.
They are likely sizing for a boat bow on or partly beam on to the waves, and are likely aiming to almost stop the boat. I think, in fact I am quite sure, there would be less strain with the stern to the waves, and the speed of the boat could be a bit higher. Anything over three feet will require a trip line to retrieve it. The drag on anything over four feet would be quite massive. That is the largest I would build, but I would have more than one. 1/2 inch polyester snaps at about 6500 pounds, and nylon at 7500 from memory. Using a really large unit could snap a lot of line. Lets hope there is room to move if it ever blows 70 or more, and the top of the waves are breaking.
Michael
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