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Sea Anchors on Catamarans

S/C-11 Catamaran, Stiletto

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S/C-11

Catamaran, Stiletto

29' x 16' x 1.4 Tons

12-Ft. Dia. Sea Anchor

Force 8 Conditions

 

File S/C-11, obtained from Thomas E. Cooke, Euclid, OH. - Vessel name Battle Cat, hailing port Sandusky, OH, catamaran, designed by Stiletto Catamarans, LOA 29' 4" x Beam 16' x Draft 48" (12" boards up) x 1.4 Tons - Sea anchor: 12-ft. Diameter Para-Tech on 300' x 1/2" nylon braid tether and bridle arms of 50' each, with 1/2" stainless steel swivel - Partial trip line - Deployed in a low system in shallow water (45 feet) on Lake Erie, about 30 miles NW of Cleveland with winds of 40 knots and choppy seas of 8-10 ft. - Vessel's bow yawed 10° - Drift was estimated to be about 300' per hour during 10 hours at sea anchor.

Another difficult situation involving a lightweight multihull, shallow water, low visibility (night), uncertain position, crew fatigue, impaired judgment, vicious squalls and nasty seas, all brought under control by the use of a parachute sea anchor. Transcript:

I have sailed Lake Erie now for four years with the sea anchor on my boat. This is the first time I had a real life-threatening situation where options were limited, and thank God the sea anchor was one of them. To make a long story short, we tried to beat a low pressure system moving in from the southwest, and couldn't. In our haste to outrun this system I made some bad navigation calls, and we ended up following a freighter for about an hour and a half out into Lake Erie's open water, mistaking its lights for the lights of Cedar Point Amusement Park at Sandusky Bay. By the time we figured out we were following a freighter, weather conditions began to deteriorate.

It was 3:00 a.m. when we saw lightning in the west. Diminishing visibility along with increased wind and waves quickly followed. Within 15 minutes we went from 10 knots of wind, 1-2' waves, a starry sky and some lights visible on shore, to 20-25 knots of wind, 5-6' waves, a black sky, literally no horizon and thunder on the increase. The only means of navigation on board were two Horizon compasses. We had no auto-pilot and had been up for 20 hours. We were extremely fatigued and totally disoriented. With no horizon and our brains not functioning too well, (extreme fatigue does funny things to the mind) we decided to deploy the sea anchor and wait until daylight before doing anything else. We deployed the sea anchor in text book fashion. We have the DSB (deployable storage bag). Nothing fouled up, it was almost too easy. The boat slowly drifted downwind and when the rode ran out she swung straight into the wind. At that point we just rode the waves. We lashed sails down and made sure everything was secured and that was all there was to it. On board with me was my sailing buddy, Tom, and my two sons Michael & Bruce. Mike is 9 yrs. old, Bruce is 12 yrs. old and Tom is 37 yrs. old. We contacted the Coast Guard to let them know approx. where we were & what we were doing. At this time the wind was blowing a steady 28 knots & seas were building. It was hard to see how big the waves were with just a flashlight, but the white caps were all over & easy to see.

Tom & I went down below to get some sleep while my son Bruce sat in the cockpit and kept an eye out for freighter lights. By daybreak the wind was blowing steadily in the upper 30's and low 40's, occasionally hitting 48 & 50 knots. The waves were averaging 8' with 3 sets of 10'+ waves every 13th wave. The high wind & waves lasted about six hours & eventually died down to 20-25 knots and 5-6' waves. While we were on sea anchor, listening to channel 16, the Cleveland, Detroit and Fairport Coast Guards were looking for two fishing boats reported overdue the previous night. Both were power boats, one with two adults the other an 18' Bayliner with two adults and three children on board. I can't tell you the compassion we had for them knowing what they had to be dealing with, and at the same time the security we felt while at sea anchor. By the way, both boats and all aboard were found safe the following day, having been blown across the lake to Canada.

Eventually when the wind & waves died down we just powered up to the chute trip line, pulled it, the chute collapsed, we pulled it on board and the rest is history.

A few observations:

1) I never ever thought I would be caught out on Lake Erie in those conditions and survive to tell about it.

2) The sea anchor worked better than I had ever imagined. The boat rode the waves beautifully, up and down, never burying a bow. Came close, but never happened.

3) We would get sea sick only if we went down below and kept our eyes open. If we went down to sleep we were OK. We spent most of our time in the cockpit looking at the waves and how well the sea anchor worked.

4) The boat yawed very little, almost unnoticeably. We tracked drift by movement past commercial fishing nets.

5) The security we felt while being at anchor under those conditions was unbelievable. I would never have thought it possible.

6) After this experience, it is my opinion that no boat should venture offshore without the safety and security of a good sea anchor, tailored for specific boats. At the time, the sea anchor was more important to us than any other piece of safety equipment we had, including the VHF and EPIRB.

Sea Anchors on Catamarans

S/C-10 Catamaran, Iroquois Mk II

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S/C-10

Catamaran, Iroquois Mk II

30' x 14' x 3.5 Tons

12-Ft. Dia. Sea Anchor

Force 8-9 Conditions

 

File S/C-10, obtained from Rudolph L. Kirse, III, Palm Desert, CA. - Vessel name Banana Split, hailing port Palm Desert, Iroquois Mk II catamaran, designed by McAlphine Downie, LOA 30' 6" x Beam 14' x Draft 5' 6" (18" board up) x 3.5 Tons - Sea anchor: 12-ft. Diameter Para-Tech on 500' x 1/2" nylon three strand tether and bridle arms of 40' each, with 1/2" galvanized swivel - Full trip line - Deployed in a gale in deep water about 200 miles east of New York with winds of 40-50 knots and seas of 18-20 ft. - Vessel's bow yawed 10° - Drift was about 5-6 n.m. during 15 hours at sea anchor.

Rudolph Kirse III, singlehander, mariner and author, was sailing Banana Split to Bermuda from Montauk, Long Island, when the barometer began to fall. The first paragraph of the following is an excerpt from an article entitled Gunkholing, by Rudolph Kirse III, appearing in the March/April 92 issue of Multihulls Magazine (reproduced by permission). The second paragraph is a transcript of the feedback Shane Victor received from Rudolph Kirse III:

By 4 p.m. a storm had sprung up off the south New Jersey coast. It was traveling north, winds gusting to 45 knots and creating 20-25 ft. seas. By 5 p.m. all sails were down, and I was running before the wind... back to Long Island. With a lee shore fast approaching and night setting in, I decided to come about and set a para-anchor on 500' of 1/2" line, with an accompanying float and trip line. It did all, and more, of what it was supposed to do. According to both the GPS and the Loran, I drifted no more than a third of a mile per hour, with the bows held into the waves and only spray coming on board. By noon of next day, the storm had passed (later I learned that three boats had sunk, and one person was lost).

Neither I nor the boat would be here without the sea anchor. This storm came up with no warning (VHF, NOAA, Fax, etc.). Everything worked well on deployment. Boat rode easily with some pounding on hulls (lee boards half down as per your suggestion) rudders up & lashed, virtually no pounding on cabin underside. Chafing was solved on bridle by putting "poly-tubing" on line, 3' sections before eye-splicing, then held in place by whippings. Float was 3' inflated ball type anchor float. At approx. 1:30 p.m. a commercial fishing boat ran over and cut the [full] trip line. Later on had many problems trying to get anchor in - dislocated my wrist while trying to winch in the parachute. Anchor was finally brought in by removing bridle from bow and floating it off, tied to four life jackets [then powering up to the recovery float].

 

Sea Anchors on Catamarans

S/C-9 Catamaran, Crowther

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S/C-9

Catamaran, Crowther

36' x 17' x 6 Tons

24-Ft. Dia. Parachute Sea Anchor

Force 8-9 Conditions

 

File S/C-9, obtained from Gary Jones, Rockville, MD. - Vessel name Corinthian XIII, hailing port Chester River, MD, "Witness" catamaran, designed by Lock Crowther, LOA 36' x Beam 17' x Draft 2' x 6 Tons - Sea anchor: 24-ft. Diameter military chest reserve parachute on 450' x 3/4" nylon three strand rode and bridle arms of 25' each, with 5/8" galvanized swivel - Full trip line - Deployed in low system in shallow water (12-15 fathoms) about 50 miles SE of Cape Fear, NC, with winds of 35-45 knots and seas of 8-12 ft. - Vessel's bow yawed 10° - Drift was estimated to be 5 n.m. during 10 hours at sea anchor.

Parachute sea anchors are worth their weight in gold in difficult coastal situations with the wind on the rise and the crew sick and exhausted. Their low rate of drift means that they require practically no sea room, making them the only viable means of stopping the boat and calling "time out" in close quarters. Transcript:

Wind and sea started building about 1800 hrs as we came up on Frying Pan Shoals. With the wind on the nose and the sea becoming choppy we weren't making any progress toward Charleston, South Carolina. At midnight the wind had turned the sea white and many waves were coming over the bow. We were heavy with provisions for a long cruise and five people were aboard. One crew member got sick and the rest were exhausted from fighting the weather.

The prospect for weather during the next 8 hours sounded bad and we knew the chances of being set into the shoals were great, so we decided to set the chute. Holding onto the heaving deck with one hand and setting the chute was tough due to water coming over the bow. It took 1.5 hours to deploy the rig, but it worked great and gave us time to go below and get much-needed rest.

Sea Anchors on Catamarans

S/C-8 Catamaran, Kelsall

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S/C-8

Catamaran, Kelsall

36' x 20' x 4 Tons

18-Ft. Dia. Sea Anchor

Force 11-12 Conditions

File S/C-8, obtained from Rick Kazprzak, Kodiak, Alaska - Vessel name Catherine Estelle, hailing port Kodiak, "Tonga Tora" catamaran, designed by Derek Kelsall, LOA 36' x Beam 20' x Draft 18" x 4 Tons - Sea anchor: 18-ft. Diameter Para-Tech on 450' x 5/8" nylon three strand tether and bridle arms of 50' each, with 5/8" galvanized swivel - Partial trip line - De-ployed in a storm in the Gulf of Alaska about 350 miles west of Queen Charlotte Island, with winds of 70-80 knots and seas of 30-40 ft. - Vessel's bow yawed 10° - Drift was estimated to be about 5 n.m. during 48 hours at sea anchor. 

Linda Kasprzak read the second edition of the DDDB and urged Rick to equip Catherine Estelle with a Para-Tech sea anchor. She also saw to it that tether, bridle, hardware and all fitting were ready to take on the Gulf of Alaska.

Rick and Linda Kasprzak left Kodiak on 13 July 1991, headed for Vancouver Island, 1200 miles as the crow flies straight across the Gulf of Alaska. At the half way point they ran into one major storm, one gale, and one minor gale, spending a total of five days tethered to the sea anchor. There were some anxious moments.

The transcript of an official Coast Guard document (CG Juneau, Archive Number 2285) reads as follows: Urgent Marine Information Broadcast - Communications have been lost with the S/V Catherine Estelle endangered by weather in position 53-05 N, 142-65 W. The vessel is a 37 ft. catamaran with 2 persons on board. Vessels in the vicinity are requested to keep a sharp lookout, assist if possible, and advise the nearest CG station.

At the time of this urgent broadcast Catherine Estelle was being held to survival by the long rode leading the Para-Tech sea anchor. Transcript:

The storm we encountered was a major one with a very quickly dropping barometer (1 millibar every 1/2 hour). At the height of the storm we encountered 35-40 ft. seas. I believe I am under-estimating this as the seas were so big that our GPS could not get a fix at times, because it was being blocked out by the huge waves.

Surface analysis chart of the Gulf of Alaska for Sunday 21 July 1991, showing the Aleutian Islands on the upper left, Alaska and Canada on the upper right, and Vancouver Island on the right. Catherine Estelle's position at this time was 53° 15' 42" North, 142° 36' 09" West, which would place her right in the center of the LOW. Note the 2200 mb HIGH to the north. (Courtesy of University of Alaska).
Surface analysis chart of the Gulf of Alaska for Sunday 21 July 1991, showing the Aleutian Islands on the upper left, Alaska and Canada on the upper right, and Vancouver Island on the right. Catherine Estelle's position at this time was 53° 15' 42" North, 142° 36' 09" West, which would place her right in the center of the LOW. Note the 2200 mb HIGH to the north. (Courtesy of University of Alaska).

               Wind speed increased at the start from 40 to easily over 70 knots. The seas were nothing but white spray, breaking crests and huge waves. We have lived in Kodiak for 15 years and so have experienced many a storm, but have never seen anything like we experienced during those 48 hours. The situation was so bad that we were dressed in survival suits and had the catamaran ready so that if we flipped, we could have access to our EPIRB, survival food and water.

The boat handled very well, but it was unnerving to be held to survival by a thin 5/8" line. Sleep was impossible. The sea anchor definitely saved the boat and I'm sure our lives. It operated flawlessly on those 2 days and the other 3 days during the other 2 gales.

We had 50' bridle arms that went through a specially made SS bow plate, but we had also built a U-bolt to this plate. The bridle was encased in 1/4" thick rubber tubing where it hit metal on the plate. We had a little trouble deploying the sea anchor, mainly because we have a seagull striker in front, plus 2 head stays. But once around all that, we were able to set the anchor just fine. Our catamaran rode these huge seas like a duck rides a wave on the sea anchor. But because the seas were so big, we did have a lot of noise due to waves slapping on the under-body.

The bottom line is that the 18-ft. para-anchor operated as you said it would, and with your help, my wife Lin's forethought, and a well-designed boat, we all did what should have been done and came through a very violent storm and survived with NO damage. Mr. Kelsall must be commended on his fine design of this boat.

Rick & Linda Kasprzak have since logged thousands of miles and used the same sea anchor in other marginal situations. In a letter to your author dated 16 September 1991, Rick wrote about one other episode. At the time Catherine Estelle was beating against 30 knot winds and 10-15' seas when a big wave slammed into her. There was a loud bang. A frantic search revealed that a weld had broken on one of her rudders.

The sea anchor was immediately deployed to bring the situation under control and wait for calmer seas. A radio call to the Canadian Coast Guard brought a response from a nearby fishing boat, with an offer to tow the catamaran to Bella Bella (the nearest port).

In the radio conversation that followed, the skipper of the fishing boat expressed concern about the initial pick-up and transfer of tow line in rough seas. He said he had seen more damage occur in this transfer than in any other situation in all the towing experiences he knew of. Rick Kazperzak:

I said to the captain of the fishing boat, "No problem! Just pick up the trip line connected to the red buoy, pull the chute in, bag it temporarily on deck, then cleat the tether and start your tow."

The fisherman had no problem doing this. He towed Catherine Estelle to a small bay in Bella Bella, and then released the tow - dropped the parachute back in the water and went on his way. Rick Kasprzak:

 The point is this: here is another safety use of the sea anchor - towing. Easy pick up of tow line and easy release.

NOTE: When it come to tow lines the Coast Guard will not go along with the above proposition. It has always been the policy of the US and Canadian Coast Guards to use nothing but their own tow lines in all operations. They will not tow a vessel with anything else because they don't want to be liable for failure of the rope - and damage or injury resulting from that failure. See also Captain Bob Proulx's Coast Guard experience in File S/M-23. However, the above proposition is eminently logical when receiving a tow from a friendly fishing boat or pleasure vessel.

SC8
EASY TOW LINE TRANSFER

 

Sea Anchors on Catamarans

S/C-7 Catamaran, Wharram

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WHARRAMS/C-7

Catamaran, Wharram

35' x 17' x 3 Tons

9-Ft. Dia. BUORD Sea Anchor

Force 8-9 Conditions

 

File S/C-7, obtained from Roger Ayers, Ft. Lauderdale, FL. - Vessel name Marney, hailing port Ft. Lauderdale, catamaran ketch, designed by James Wharram, LOA 35' x Beam 17' x Draft 2' 6" x 3 Tons - Sea anchor: 9-ft. Diameter BUORD on 300' x 1/2" nylon three strand tether and bridle arms of 25' each, with 1/2" galvanized swivel - No trip line - Deployed in a low system in 100 fathoms about 25 miles east Cape May, with winds of 35-45 knots and seas of 10-12 ft. - Vessel's bow yawed 30° - Drift was estimated to be 12 n.m. during 6 hours at sea anchor.

 

Marney, a 35-ft. Wharram "Tangaroa" was home-built by Roger and Marney Ayres, who have been chartering, delivering and crewing yachts on the east coast, the Caribbean and Europe. In June '85 they were sailing her to Florida when they were overtaken by a frontal system off the coast of New Jersey. The wind was blowing Force 7-8, contrary to a southerly current, producing steep, short-duration seas of 10-12 ft. They deployed a 9-ft. diameter BUORD. The parachute was not big enough to do an adequate job of keeping Marney pointed into the seas. Her twin bows were yawing about 30° off to each side - through an arc of 60°. The rudders seemed to be under inordinate strain as well. Transcript:

We were caught departing from Cape May with a good forecast of 10-15 knots. As the afternoon wore on and we reached out, the wind freshened. We decided to beat as far offshore as possible, which we did, finally reduced to storm staysail and a double-reefed main. In this, our first real blow in this boat, we were not operating as "professionally" as we might have, and concerned ourselves only with getting offshore in case the wind backed further to the east, not noting our exact position, etc. just beating on [trying to gain ground].

The sea anchor was deployed from the bows, but allowed too much leeward drift (estimated 2-3 knots), and also allowed us to fall back off the steep, short seas, which had built up in the southerly current. I think that falling back off a larger 15 ft. wave at an angle, we broke both tillers. Note that a catamaran with two large transom-hung rudders, when backing into a trough and burying the sterns, exposes two blades, and two sets of cheeks to the force of the water, approximately 4 times the area of a typical trimaran spade rudder. It is therefore essential that this type of boat (like a Wharram) make no sternway, else use the sea anchor off the stern.

We are saving the BUORD for use as a "lunch hook," but now have a 24' diameter parachute for use off the bow.

 

The lineage and heritage of James Wharram designs lead back to the Aka Taurua, 60 ft. double-hulled ocean voyaging canoes with which ancient Polynesians explored and settled every island within 15,000 square miles of the greatest ocean on earth. These ancient mariners used "sea anchors" consisting of stones with holes drilled in them, tethered to the bows by means of hibiscus fiber rope.
The lineage and heritage of James Wharram designs lead back to the Aka Taurua, 60 ft. double-hulled ocean voyaging canoes with which ancient Polynesians explored and settled every island within 15,000 square miles of the greatest ocean on earth. These ancient mariners used "sea anchors" consisting of stones with holes drilled in them, tethered to the bows by means of hibiscus fiber rope.

 

Sea Anchors on Catamarans

S/C-6B Catamaran, Crowther

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S/C-6B

Catamaran, Crowther

43' x 25' x 7.5 Tons

18-Ft. Dia. Sea Anchor

Force 10 Conditions

 

File S/C-6B, second file (see S/C-6A) obtained from Josh Tofield of Tucson, AZ. - SAME VESSEL - SAME SEA ANCHOR - SAME BRIDLE & TETHER DIMENSIONS - Deployed in a storm in deep water about 800 miles northeast of Hawaii with winds of 50-55 knots and seas of 25 ft. - Vessel's bow yawed 10° - Drift was 5 n.m. during 72 hours at sea anchor.

This is the second file involving Ariel. In the previous file she successfully rode out Force 8-9 conditions on the same parachute with a 250' tether. In this file we see that the 250' tether was clearly too short when Ariel ran into a much heavier storm on her way back from Hawaii. The 250' x 3/4" tether was not long enough to provide adequate shock absorption, as a result of which the boat took a severe pounding. Ariel's tether should have been at least 400' in this instance (the general rule of thumb being LOA x 10). Transcript:

Ariel departed Hawaii 11/10/91 with delivery skipper aboard. He has documented over 100,000 miles in deliveries for Compass Yacht Services alone. Approx. 800 miles NE of Honolulu a rapidly moving, intense LOW which was squeezing against a massive hi-pressure cell caught Ariel in the exact center of reinforced winds. Barometer dropped from 1018 to 1002 in 3 hours! (Weather Fax attached). Wind started one hour later and built to Force 10 where it stayed, never dropping below Force 9 in 48 hours. Waves were 25' (conservatively measured from the back of wave height and not from the troughs). Bridle (3/4" nylon) chafed completely through & had to be replaced with 5/8" backup bridle. Later one leg of the 5/8" bridle SNAPPED in the center when hit with very large wave, throwing Ariel backward, shearing the foam & fiberglass off of one rudder completely, and leaving only half of the other rudder (which later broke off). Crew eventually added 100-150' of anchor chain to the 250' of 3/4" nylon tether and rode out the rest of the storm.

Recovery, using the "partial trip line" was very difficult. Engines both out because during the storm, while motoring up to relieve pressure on bridle (while changing it) a large wave submerged entire stern, forcing water up exhaust system and drowning the engines (exhausts 2' above waterline under aft bridge deck !!!!!) Jury rigging done after storm passed. Ariel was then sailed 1500 miles to San Diego. Moral of the story: USE LOTS OF PRIMARY TETHER! What is adequate for Force 9 is not adequate for Force 10!

Sea Anchors on Catamarans

S/C-6A Catamaran, Crowther

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S/C-6A

Catamaran, Crowther

43' x 25' x 7.5 Tons

18-Ft. Dia. Sea Anchor

Force 9 Conditions

File S/C-6A, obtained from Josh Tofield, Tucson, AZ. - Vessel name Ariel, hailing port San Diego, catamaran, designed by Lock Crowther, LOA 43' x Beam 25' x Draft 3' 3" x 7.5 Tons - Sea anchor: 18-ft. Diameter Para-Tech on 250' x 3/4" nylon three strand tether and bridle arms of 75' each, with 5/8" galvanized swivel - Full trip line - Deployed in a tropical depression in deep water about 400 miles SE of Cabo San Lucas, Mexico, with winds of 45-60 knots and seas of 18 ft. - Vessel's bow yawed 10° - Drift was 2 n.m. during 20 hours at sea anchor (confirmed by GPS).

Several weeks after Ariel left San Diego for points south she ran into an unforecast loop of ITCZ - Inter Tropical Convergence Zone - at 21° 09' North, 106° 52' West. In his book, Weather For The Mariner, William J. Kotsch has this to say about the phenomena (Naval Institute Press, reproduced by permission):

     "The ITCZ is usually characterized by strong, ascending air currents, a great deal of cloudiness, and frequent heavy showers and thunderstorms. The intensity does, however, vary greatly. Sometimes the ITCZ looks like a tremendous wall of black clouds, with the top extending to 55,000 feet and higher.... The width of the ITCZ varies from about 20 to 150 nautical miles, and as a general rule, the narrower the zone (i.e., the greater the convergence), the more intense is the weather associated with it. When the ITCZ is near the equator, only small and weak cyclonic circulations can develop within it. But when it migrates away from the equator (at least five degrees or more), the influence of the earth's rotation becomes great enough to transfer sufficient "spin" to the converging air currents to permit tropical cyclones, hurricanes, and typhoons to develop."

One really needs a chart of Mexican waters to appreciate the value of a parachute sea anchor in tight quarters. Ariel was about 100 miles off the Mexican coast proper, with the rocky islands known as Tres Marias to her lee. The crew consisted of owner Josh Tofield, his wife, and two small children. Tofield deployed an 18-ft. diameter Para-Tech sea anchor and "anchored" Ariel to the surface of the sea.

Tres Marias is a Mexican prison compound. There is a 20-mile forbidden zone around it and pleasure boats have been known to be rammed by gunboats for intruding into the zone. It being dark, and apprehensive about getting too close to the islands, Josh Tofield kept a close eye on the GPS readings. Incredibly, he found that Ariel drifted no more than 2 nautical miles in the 20 hours that she was tethered to the sea anchor. Transcript:

Only 100 miles from Puerto Vallarta and with the Islas Tres Marias in our lee we got caught in a brief but fierce (unpredicted by WX or WXFAX) loop of ITCZ convection sucked up to our latitude. Winds of 45 knots sustained, gusts to 60 for 6-8 hours, with 30-35 knots sustained for 6-8 hours before and after. As long as the wind was blowing from the SE the seas were highest - but also most comfortable, as our catamaran rocked up and down in 18-ft. maximum seas, with 3-ft. breaking tops, and almost no side to side [yawing] motion. However, as the wind veered, large cross swell came under and slammed bridge & deck viciously - but no damage and no excess heeling.

My alternative would have been to run off to the West - which we could have done - but I didn't want to as we would have been blown all the way to Cabo before the wind subsided.

Only problem was the trip line. Perhaps I tied it on wrong to its small swivel, but it fouled fender severely and pulling in required anchor windlass and much bad language!

ADJUSTING BRIDLE FOR BEST RIDE.
ADJUSTING BRIDLE FOR BEST RIDE.

This is one of numerous files in which boats had problems with fouled up trip lines. Yet another reminder that FULL trip lines should be kept fairly taut at all times (see Fig. 39 and review last paragraph of file S/T-7). Also, the problem relating to cross swells mentioned by Tofield can in most instances be lessened by adjusting the lengths of the bridle arms on multihulls. By shortening one bridle arm and lengthening the other (Fig. 41) it is possible to rotate the bows into a direction more accommodating to changing sea conditions. If the wind and dominant waves have been coming from the north (0°), for example, and a secondary disturbance begins to squeeze in a different set of waves from the northeast (45°), the skipper may wish to adjust the bridle arms so that the bows are pointing somewhere in between the two sets of waves (about 22°).

Sea Anchors on Catamarans

S/C-5 Catamaran, Walter Greene

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S/C-5

Catamaran, Walter Greene

50' x 30' x 5 Tons

4-Ft. Dia. Sea Anchor

Force 9 Conditions

 

File S/C-5, obtained from Walter Greene, Yarmouth, ME. - Vessel name Sebago, catamaran, designed by Walter Greene, LOA 50' x Beam 30' x Draft 7' (20" board up) x 5 Tons - Sea anchor: 4-ft. Diameter Shewmon on 250' x 3/4" nylon braid tether and bridle arms of 50' each, with 1/2" galvanized swivel - No trip line - Deployed in a whole gale in deep water in the middle of the North Atlantic with winds of 40-50 knots and seas of 25-30 ft. - Vessel's bow yawed 45-60° - Drift was estimated to be 30 n.m. during 48 hours at sea anchor.

By way of a brief digression we should perhaps mention a previous experience of renowned multihull designer Walter Greene, an experience that ushered in a new era in SAR (search and rescue). Indeed the experience marked a point in maritime history when it became possible to ensure the safety and survival of human life at sea to an extent never before possible.

On 10 October 1982 Greene was sailing his 50' trimaran Gonzo to St. Malo, France, when it capsized in a violent North Atlantic storm 300 miles south-east of Cape Cod. The boat had been running before 30-ft. seas without a drogue when she was picked up and thrown by a huge wave - she broach-capsized when one of her bows dug into green water. Once over the initial shock of the capsize, Greene and his well-prepared crew jumped into action. In no time they had donned their immersion suits, lashed themselves to the upturned, floating, hull, and switched on the EPIRB - Emergency Position Indicating Radio Beacon.

It was the navigation officer on board TWA's flight 904 that first heard the lonely wailing of Gonzo's EPIRB (the signal is swept audio tone, sounding like a miniature "wow-wow" police siren). The information was immediately relayed to the FAA's Oceanic Control at Islip, New York, which in turn informed Atlantic Rescue at Scott Air Force Base in Illinois.

At that time (1982) SARSAT - Search And Rescue Satellite-Aided Tracking - was not quite operational, but a participating Russian satellite, Cospas, was known to be overhead. Scott AFB obtained an uplink and sure enough, no sooner had Cospas signed on than it confirmed a "hit." The satellite then provided data and telemetry needed to pinpoint the position of the distressed vessel. Atlantic Rescue then broadcast an urgent All Ships Bulletin, and the tanker California Getty was diverted to the scene. At the same time, the Coast Guard Air Station at Elizabeth City North Carolina was briefed and advised to launch a C-130 search plane, which picked up Gonzo's EPIRB signal, homed in on it and dropped two datum marker buoys (which transmit additional homing signals on a different frequency).

The tanker California Getty was the first on the scene, but failed to effect safe rescue in the 25 ft. seas, standing off to windward to provide a "breakwater" for the disabled trimaran. And there she stayed, "like a big Saint Bernard," until the 210' Coast Guard Cutter Vigorous arrived on the scene.

One by one the three survivors were taken off to safety, concluding one of the most remarkable rescues in maritime history -one of the first in which a satellite played an instrumental role. (A quick reminder that SARSAT is now fully operational in most areas of the world and any sailor with a Class A EPIRB can access the grid to get a distress signal through to international Search & Rescue agencies).

Walter Greene happily went on to design many more multihulls and four years later used a sea anchor on board his 50' catamaran, the infamous Sebago. The 4-ft. diameter Shewmon sea anchor was deployed off the bow, but was too small to do a satisfactory job (the same sea anchor did a lot better when used off the stern - see file D/C-1.) The bows of the big catamaran yawed past 60° at times.

Shewmon sea anchors are available in many sizes, up to 33 feet in diameter. Literature published by Shewmon, Inc. would seem to indicate the need for an 8-10 ft. diameter Shewmon sea anchor for a boat the size and weight of Greene's Sebago.

Why did Walter Greene choose a 4-ft. diameter sea anchor instead? Likely he was worried about a bigger one being too "unyielding." Victor Shane ran into this same apprehension among other multihull sailors. To this day some of them will react with alarm at the very idea of tethering their boats to a large diameter, "unyielding" sea anchor in a gale.

Sea Anchors on Catamarans

S/C-4 Catamaran

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S/C-4

Catamaran

40' x 20' x 3.5 Tons

12-Ft. Dia. Parachute

Force 7 Conditions

 

File S/C-4, obtained from Sackville J. Currie, Blaney, Ireland - Vessel name and design unspecified, hailing port Tokyo, catamaran, LOA 40' x Beam 27' x Draft 6' x 3.5 Tons - Sea anchor: 12-ft. Diameter Para-Tech on 60' x 1/2" nylon braid with 1/2" galvanized swivel - Emergency deployment when the windward ama broke off in shallow water (100 fathoms) five miles off Cape Nojima, Japan, with winds of 30 knots and confused seas of 12-15 ft. - Occupants were taken off by a Japanese Coast Guard helicopter.

File S/C-4 illustrates the value of a sea anchor in one of many likely damage control situations. En route to Sendai this 40-ft. catamaran sailed out of Tokyo Bay and, rounding Cape Nojima to head north, ran into 30-knot winds blowing contrary to a local current.

After considerable heavy labor against 12-15' steep, confused and choppy seas the windward pontoon suddenly broke off, leaving the catamaran lame and disabled seven miles offshore, now rapidly drifting out into the open sea.

The owner's main concern was that the boat might tack and, with the one ama broken off, capsize. He immediately deployed a 12-ft. diameter Para-Tech sea anchor off the bow of the remaining hull. The sea anchor held the lame boat more or less head-to-sea, preventing capsize and at the same time keeping the crippled vessel from drifting out of the shipping lanes and into the great Pacific. With the situation temporarily stabilized and the motion of the yacht eased, distress flares were then launched which were spotted by a passing freighter. The captain of the freighter radioed the Japanese Coast Guard, which sent a helicopter to the scene and plucked the survivors off the multihull. The boat was then abandoned to the raging seas, still tethered to its 12-ft. diameter, orange-colored parachute sea anchor.

Sea Anchors on Catamarans

S/C-3 Catamaran, Prout Snowgoose

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S/C-3

Catamaran, Prout Snowgoose

37' x 16' x 6 Tons

12-Ft. Dia. Sea Anchor

Force 9 Conditions

 

File S/C-2, obtained from William E. Masters, Columbus OH. - Vessel name Rhayader, Snowgoose catamaran, designed by Prout, LOA 37' x Beam 16' x Draft 2'6" x 6 Tons - Sea anchor: 12-ft. Diameter Para-Tech on 300' x 3/8" nylon three strand tether and bridle arms of 12' each, with 5/8" galvanized swivel - Full trip line - Deployed in a whole gale in the Bay of Biscay, and also in a low system near the Bahamas with winds of 35-60 knots and seas of 20-30 feet. - Vessel's bow yawed 10° - Drift was estimated to be 12 n.m. during 66 hours at sea anchor.

Rhayader, a handsome 37-ft. "Snowgoose" designed and built by the Prout brothers, was purchased in England and sailed across the Atlantic in April 1987. The owner, William Masters, used a 12-ft. diameter Para-Tech sea anchor in a gale in the infamous Bay of Biscay. Winds were then sustained at 45 knots, gusting to 60. The sea anchor was used again about a year later when Rhayader ran into a low system stalled off Bermuda. When a low system gets stalled for an extended period of time, even if it is only packing thirty knot winds it will eventually begins to generate huge waves and swells. On the DDDB form that Masters sent back he indicated that some of the combined seas were higher than 30 ft. On this second occasion Rhayader was tethered to the sea anchor for 66 hours. Transcript:

During the 66 hour period, the seas and wind averaged 040° True. Our drift was 262° True, probably tidal set onto the Bahamas Banks. Also, in April of '87 while sailing to the Canary Islands from England, we deployed the para-anchor off the Continental Shelf, depth unknown. Winds were easterly, sea from the northwest. Nasty. Seas were short and steep (200-250' crest to crest. Winds were steady 45 knots, gusts to 60 knots. Hove to the para-anchor for 22 hours. Drift was 2 n.m. west. Thanks, para-anchor, and of course the Casanovas. I wouldn't leave port without it.