Attaching Sea Anchor on larger multihull

[mikereed100]

Originally Posted by nfbr

Outstanding. Thank you.
Do you attach to the end of the parachute rode on a spliced loop, or does the cow hitch "grab" the rode?

I put eye splices in the ends of the rode and the bridle arms. The bridle arms are then attached to the end of the rode with cow hitches aka 'luggage tag' hitches. I like this method as, theoretically, you retain 100% of the rode strength.

[grantheadifen]

I'd be interested in the final conclusion and a quick hand sketch. We'll draw it up properly and post it into our catamaran course online at NauticEd.

[Mark Johnson]

Originally Posted by nfbr

When I bought my cat (61ft, daggerboard) it came with a large parchute sea anchor. 25 yrs old. Never used.

So, if I wanted to use it, I've been trying to figure out how to rig and deploy it. Probably why it was never used.

Keeping in mind I have a bowsprit, so opportunities to tangle are endless.

Anyway, lets say it's a big storm, I'm tired and don't want to use a drogue, but face it head on to get some sleep. And we can argue the stupidity of that seperately (Drogue device database).

The books I find are very dated, and seem to not use a bridle. Instead they rig the sea anchor line to one hull and use a pulley to pull it across.
That won't work on my boat. Padeyes are too far down on nose of hulls.

So I have gotten as far as the below:

Attaching

Attach an extra long (2.5 times beam) nylon bridle to anchor padeyes on front of bow, possibly using dyneema soft shackles. Bridle having a spliced eye in the middle.

Now the next question is how to attach the anchor rode to the bridle, and how to do so in a manner that could be adjusted for chafe or length.

And how to do an adjustment using the windlass, which goes across the crossbeam, which we don't want to overload.

How do you setup a bridle with a sea anchor, and make it adjustable.

Thanks
Paul

"Anchoring and Mooring the Cruising Multihull" has a lot of good stuff on bridles, which apply to sea anchors as well. (Available from Amazon)

[capn_billl]

Originally Posted by Palarran

I decided a long time ago that using a sea anchor was not something we would ever do. The story of the Catana flipping over backwards in the Med sealed that decision but also because if the waves are truly breaking, a catamaran is not designed to handle the loads regardless of the anchor point design. The topic has been discussed many times here on CF. I base my strategy on advise from a very seasoned delivery captain with somewhere around 25 ocean crossings. His method is to run until there is no more searoom, then turn and motor into the waves slowly. This did work for me once in conditions that I can't imagine sitting stopped in with a sea anchor.

It would be nice if in the last 20 years someone had actually taken video of deploying (or even a deployed) a sea anchor in actual storm force winds. Of those that I've seen, the weather was much less than survival conditions.

It occurs to me that a breaking wave big enough to flip a boat attached to a sea anchor would also be big enough to flip a boat not attached to a sea anchor.

[Seabeau]

Originally Posted by capn_billl

It occurs to me that a breaking wave big enough to flip a boat attached to a sea anchor would also be big enough to flip a boat not attached to a sea anchor.

Given that A. Coles in his "Heavy Weather Sailing" stated that shallower draft vessels, including multihulls, were at far at lessor hazard from "tripping" due to breaking waves. Certainly for you, especially if your centerboard is up, I'd say that any drag device will be counterproductive. Let the vessel slide with the waves.

[mikereed100]

Originally Posted by Palarran

I decided a long time ago that using a sea anchor was not something we would ever do. The story of the Catana flipping over backwards in the Med sealed that decision but also because if the waves are truly breaking, a catamaran is not designed to handle the loads regardless of the anchor point design. The topic has been discussed many times here on CF. I base my strategy on advise from a very seasoned delivery captain with somewhere around 25 ocean crossings. His method is to run until there is no more searoom, then turn and motor into the waves slowly. This did work for me once in conditions that I can't imagine sitting stopped in with a sea anchor.

It would be nice if in the last 20 years someone had actually taken video of deploying (or even a deployed) a sea anchor in actual storm force winds. Of those that I've seen, the weather was much less than survival conditions.

Keep in mind that the Catana capsized because the crew were unable to properly attach the bridle in the conditions they found themselves in. They had one arm going to a bow and the other over the anchor roller at the mid point of the forward crossbeam. Had they set up the bridle prior to leaving port the outcome may have been quite different.

Motoring into the wind may work for a time on some boats, but on mine it would take close the full throttle on both engines and constant attention. How long before a typical cruising couple would become tired and inattentive?
I have spoken with 3 cat skippers who have deployed sea anchors in tough conditions, one at the edge of a hurricane. They were unanimous in their praise of the maneuver, the one that had the close brush with a hurricane credits it with saving the boat and his life.

[pbmaise]

Speaking as a bigger multihull owner who has thought about this problem over and over again...lets backup.

The OP said "lets say it's a big storm, I'm tired and don't want to use a drogue"

Really????.

Would you even think of going out onto the bows in a big storm when you are tired?

The bows of a multihull, especially a big trimaran are simply not the place to be in a big storm. This is not a monohull where the bow area is far more secure.

I have been aboard my vessel in some pretty good sized waves and I have seen what it looks like at my bows and I certainly would not want to go out there.

When I purchased my vessel I had two para-tech anchors and three lengths of Jordans. I finally got excellent advice regarding my question....how do you switch from running on Jordans to setting your sea anchor? The answer I got was NO NO NO. You can't. You have to pick one or the other and keep to that route. You simply are not going to be able to pull in your Jordan, safely turn the vessel, and then deploy a sea anchor.

The advice I received was pick your weapon and deploy well before conditions are too difficult to safely secure.

Aboard my former vessel, I sold it recently, the two ama bows had "snorkels" running forward through the strongest part of the bow. The snorkels were large nylon reinforced tubes to protect the lines. The docking cleat was then behind this point.

The greatest load on the line will occur when a wave picks up the bow suddenly. Fortunately, much of the load is imparted directly to the bow. I.E. The cleat doesn't see most of the force and then impart the load into the bow.

To thread the line into the snorkel I have to lay down on my stomach on the tip of the bow, hold the line in one hand, and thread the line up and into the snorkel. I use my legs to hug the bow to hang on while doing this, and much of my upper body is unsupported since it isn't exactly comfortable lay on the cleat. This is rather a difficult procedure to do even when stationary at the dock when I am fully rested.

Therefore, even if I set the lines for the sea anchor before a storm, I would still be risking life and limb if the waves are moderate. I would be cursing myself for not prepping the sea anchor before setting sail.

Prepping the sea anchor before sailing makes a lot of sense based upon this experience.

The bridle can be installed on the bows and led through the snorkels safely and secure while at the dock. The big caution would be to ensure the bridle didn't become loose and then start dragging when the vessel is going forward. It wouldn't be fun to have the bridle tangle with the prop.

I would keep the para-anchor itself in the ama until needed. Now deployment is just a matter of attaching the para-anchor to the bridle and then releasing the attachments of the bridle that kept it out of the water. Some bungee cords would work well.

[Kanani]

Anchoring to a sea anchor really isn't much different than anchoring in the sea bed, in a bay during a storm. Actually, it is easier (IMO), a hell of a lot more comfortable and less stress on the vessel.

I sat out a cyclone in the Tasman Sea between New Zealand and Australia for 2-days on a parachute sea anchor. After that storm, I used the para-anchor whenever the wind got up to 50+ and I had ample sea room. I can tell you from much experience, you go from "all-hell breaking loose in utter chaos" to sitting in your cockpit, sipping coffee and watching the beauty of the storm unfolding all around you. Not only does the parachute hold your position head to wind and seas but it also acts as a breakwater of sorts. I never had a breaking wave even approach my boat.

Before I deployed the para-anchor in that storm, I was constantly taking breaking waves over my 45' Passport Ketch and was knocked down twice. After deployment, the only water that I got on deck was rain water and sea-foam. The motion of the vessel was remarkably comfortable except for occasional extreme heeling in the gusts (up to 100kts), just like in an anchorage (actually... better).

I have never used a para-anchor on a multihull but can certainly appreciate the need for a proper bridal. The same could be said for anchoring in a bay, in a storm. The challenges are obvious and have been addressed by others but I disagree with some of the comments about shock load. I used 300' of 5/8" nylon road from my boat to 10' of 1/2" chain at the parachute bridal. I used a 3/4" S/S swivel at the chain to allow for the rotation of the parachute. On the boat end, I came up from the anchor locker with 25' of 3/8" BBB chain that was lead over the windlass capstan and over the bow roller. This system avoided any chafe issues. Chafe is your worst enemy. When lying too a para-anchor, your anchor rode is practically horizontal, straight out, off the bow as the parachute lays just under the surface. Shock loading from "bow lift" is NOT an issue. The anchor rode acts as a lever off of the bow roller. Remember, nylon rode will stretch up to 25% of it's length under load. Although the load is tremendous in extreme conditions, shock loading is not a big issue. Shock loading is far worse when at anchor to the sea bed in a storm because vessels use all chain rode and the sea bed is not flexible. Snubbers can only absorb so much.

The need for a bridal is obvious as well as the challenges posed. I don't quite understand the idea of some sort of adjustment to the bridal. I would think that the bridal would need to be balanced and protected from chafe but adjusting it under load would be impossible IMO. The forces of the bridal on the hull on a multihull might certainly be higher than the forces on a monohull but I would think they would be less than the forces experienced in similar conditions while attached to an anchor or mooring in the sea bed. You will find that the load on the anchor rode will make the nylon rode like a steel bar. Any apparatus that might be used for adjusting just adds potential points of catastrophic failure and potential points of chafing. If something breaks while under the forces of a para-anchor, the consequences could be dire for sure. As far as "going forward" is concerned, once on the para-anchor, I think that you will find going forward quite acceptable and far safer then going forward while not on the para-anchor.

After my 1st experience with the para-anchor taught me to prepare the anchor for deployment before leaving on any long ocean passage of 4-days or more. It's easy to set-up at dockside. Not so easy at sea in foul weather. I ran my rode on the outside of the stanchions and back to the cockpit and had my anchor bag secured and ready for deployment. I seldom used it but I was always ready and confident. When the winds got up to 50Kts+, over the side is went and all I had to do was pay out the rode from the cockpit. Once I was nose to the seas, I double checked everything and put on a pot of coffee.

[Kanani]

Originally Posted by pbmaise

Speaking as a bigger multihull owner who has thought about this problem over and over again...lets backup.

The OP said "lets say it's a big storm, I'm tired and don't want to use a drogue"

Really????.

Would you even think of going out onto the bows in a big storm when you are tired?

The bows of a multihull, especially a big trimaran are simply not the place to be in a big storm. This is not a monohull where the bow area is far more secure.

I have been aboard my vessel in some pretty good sized waves and I have seen what it looks like at my bows and I certainly would not want to go out there.

When I purchased my vessel I had two para-tech anchors and three lengths of Jordans. I finally got excellent advice regarding my question....how do you switch from running on Jordans to setting your sea anchor? The answer I got was NO NO NO. You can't. You have to pick one or the other and keep to that route. You simply are not going to be able to pull in your Jordan, safely turn the vessel, and then deploy a sea anchor.

The advice I received was pick your weapon and deploy well before conditions are too difficult to safely secure.

Aboard my former vessel, I sold it recently, the two ama bows had "snorkels" running forward through the strongest part of the bow. The snorkels were large nylon reinforced tubes to protect the lines. The docking cleat was then behind this point.

The greatest load on the line will occur when a wave picks up the bow suddenly. Fortunately, much of the load is imparted directly to the bow. I.E. The cleat doesn't see most of the force and then impart the load into the bow.

To thread the line into the snorkel I have to lay down on my stomach on the tip of the bow, hold the line in one hand, and thread the line up and into the snorkel. I use my legs to hug the bow to hang on while doing this, and much of my upper body is unsupported since it isn't exactly comfortable lay on the cleat. This is rather a difficult procedure to do even when stationary at the dock when I am fully rested.

Therefore, even if I set the lines for the sea anchor before a storm, I would still be risking life and limb if the waves are moderate. I would be cursing myself for not prepping the sea anchor before setting sail.

Prepping the sea anchor before sailing makes a lot of sense based upon this experience.

The bridle can be installed on the bows and led through the snorkels safely and secure while at the dock. The big caution would be to ensure the bridle didn't become loose and then start dragging when the vessel is going forward. It wouldn't be fun to have the bridle tangle with the prop.

I would keep the para-anchor itself in the ama until needed. Now deployment is just a matter of attaching the para-anchor to the bridle and then releasing the attachments of the bridle that kept it out of the water. Some bungee cords would work well.

Actually, the statement, "The greatest load on the line will occur when a wave picks up the bow suddenly." is not correct. Your anchor rode is paid out nearly horizontal to the parachute (most of the time). The bow lifts and falls fairly freely, like a lever. Just think of being at anchor to the sea bed with 50:1 scope.

The worst loading is after one gust passes and the vessel springs forward unloading tension, then the next gust blows the bow down and the vessel heels in the wind. As she falls back and reloads the anchor rode, the stress is tremendous. It's basically the same mechanics as being at anchor near land, only in extremely shallow water. Depending where the vessel is in the trough or top of the swell, the vessel can experience the force of the swell as well as the force of the wind. When you are laying in 50-70' seas, the parachute could actually be higher than the boat.

[Dave Isom]

A catamaran having two hulls is ideal for deploying a Para Anchor from a bridle. It will keep your bows to the sea which is what you want, not your stern, cockpit open to the following seas. However , it is vital that your boat is properly set up to take the loads and you know how to deploy and....to retrieve it. I have a Pacific Para Anchor on my 40 foot steel yacht but have so far never used it in extreme conditions. I have deployed it in 45 knots to test in a lake and being a mono you get a lot of roll which a cat will not do nearly as much. It will hold you to weather and you’ll probably move around with the seas current. The Pardys used a much smaller sea anchor on a bridle with their small monohull to create a slick which the vessel sits behind like when you heave to using backwinded reefed main or headsail( but only in winds up to about 50 knots ) . In extreme conditions a parachute anchor streamed from the bow is your best option not running off as you risk getting pitch poled.. However, as stated you must be properly prepared. In your case the bridle should be already attached to extra strong fixing points then a Spectra line run down the outside of the stanchion bases held in place with electricians cable ties and back into the cockpit where the Para anchor can be readily attached by tested shackle to an eye in the Spectra line.The Para Anchor must be deployed TO WINDWARD if not you will drift over it and likely cause tangles with your hull and rudders.
Check out the Para Anchors Australia website who make them and get in touch . They will give you all the info you need and stresses on hulls etc plus a lot of testimonials . Then go out into open sea and practise deploying and retrieving in modest conditions first.

[NevilleCat]

Originally Posted by aqfishing

Hi,

We use large parachute anchors on our squid fishing vessels in conditions no sane person would want to be in. Our vessels are typically 60-80 ft mono’s and cats with a displacement of 80 to 140 tons. Our chutes have a 15-18m diameter.

I would rig it to your regular anchor bridal using 100m of Nylon anchor rope. This allow for stretch and acts as a spring to avoid hard jerks on the anchor points. Your chute should have a swivel at the attaching point, if not you must put one. I would also suggest a second one where you attach it to the bridal.

Then most important is the retrieval. We use a large buoy on a short rope at the far end (top) of the chute to keep the chute near surface should the wind die. We then run a 13-15mm rope back to the vessel. This must be of sufficient length so it is slack while you are lying on the chute. You retrieve the chute using this trip line. It may not be practical carry a buoy on your yacht, and as soon as the wind drops enough you will want to be on your way, so you could probably do away with it. The trip line to the top of the chute is essential, otherwise you will really battle to retrieve it, especially if it sinks. I would say a small parachute on a yacht is an essential tool for bad weather, esp if sailing short handed. A 2m-5m diameter chute would be sufficient for a 40-60 ft cat.

Some people leave the trip line attached to the buoy, they then motor around and collect it. I prefer to keep it attached to my vessel as it then acts as a safety should your anchor rode snap, it just make easier safer retrieval.

Thanks so much for the info.
I wonder, can you explain a little more about the retrieval line? I'm having trouble understanding how it is rigged so it can't foul the chute or rode. Also, is it a floating line?
You say you use bridals on the monos; are they rigged off-center so your bow is laying off instead of heading directly up wind?
If not what is the purpose of the bridal in this situation given that recreational vessels generally use a bridal to reduce shock loads from an all-chain rode?
Again, thanks for your input, I understand the fishing fleets in a few places around the world regularly use para anchors so it's great to hear from regular users of the technique. It seems we may be overthinking the set-up, but obviously with the forces involved it needs to be simple and strong, so interested especially in what techniques regular users have settled on.

[Kanani]

I have heard the Pardy's para anchor bridal system touted on more than one occasion. Having used the para anchor myself in extreme conditions, I will tell you that their bridal system is absolutely the WRONG thing to do.

If you have ever been anchored in a bay somewhere, in a storm, you should be well aware of how much a monohull can tack through the wind gusts. This is magnified when anchoring on nylon road because the road stretches in the gusts and the vessel springs forward in the lulls and often passes through the eye of the wind before getting blown down by the next gust. Leaving the rudder to leeward when hove-too keeps this from happening but when at anchor, the vessel has extra propelling force of the stretched rode to move the bow across the wind because it is not allowed to drift slowly to leeward. The bow is captured by the anchor rode which will pull it through the eye..

The same mechanics apply when attached to a para anchor. If you have a bridal set up to keep the wind off one side of the bow, there is a very good chance that the bow may cross the wind and the bridal is now across the deck and against the mast (or under the boat and against the keel) which will roll the boat over in the next gust. Not to mention the fact that the wind and sea forces would be doubled because of exposing more surface area to the stresses.




I read that article that the Pardy's mentioned that tactic and I thought about it one time when I was in resting in rather moderate conditions, in the Southern Ocean, on my way to Antarctica. The reality of actually doing that struck me and was was appalled that someone would suggest that. The problem is, once you deploy the para anchor, you are pretty well committed and if conditions deteriorate, you had better be prepared for that. The idea of trying to let loose of some sort of bridle and the timing of all that is not nearly as simple as it sounds and catastrophe would be hard to avoid if conditions got worse.

Running the para anchor off of the bow is a safe, effective heavy weather strategy that has been effective for many years.

[NevilleCat]

Sorry, "bridle" not bridal...
not married to it...although if in the ultimate storm maybe 'death do us part" could be appropriate?

[BigBeakie]

Kanani,

It's great to get this feedback from someone who's used a para-anchor in challenging conditions. I'd be very interested to hear your opinion on the issue of the rode material choice. There seems to be 3 choices:
1) nylon that stretches to absorb the wave forces, but then it can slingshot you forward in the lulls, which may result in higher shock loading of the rode. Also nylon is weaker when wet and seems the fibers can heatup from the energy of stretching & become weaker over many cycle,
2) poly double braid which has less stretch and hopefully remains stronger,
3) dyneema used with chain in the rode ( so called constant tension technique) to provide water resistance as the rode is pulled tight and up through the water column. This supposedly replaces the stretch of the nylon. Obviously the float on the para-anchor must support the weight of the chain and chute so it doesnt sink down when the wind abates. This would provide a very strong rode that maintains strength & cuts down on weight and aids retrieval.

What are your thoughts about the best choice for the rode, now that dyneema is more available and affordable?

[Fi2010]

YouTube has an excellent video originally published in 2003, which demonstrates the proper use of two types of multihull bridles with a para-anchor. It also demonstrates the proper use of the pendant line bridle as well as the correct retrieval of the para-anchor.

Despite what some of you are stating, the Pardeys’ used the para-anchor properly and had many successes as proven in their Storm Tactics book.

Salty Dawg also published an excellent article on the proper rigging techniques to avoid shock loading with parachute sea anchors. Since the information was published by a research expert associated with our company, we’re unable to supply links per forum rules. However, many of you are already familiar with the work and are permitted to supply the links.

We understand some of you have different intentions with this thread and will likely avoid mentioning relevant information regarding the para-anchor.