46' x 13 Tons, Fin Keel
18-Ft. Dia. Para-Anchor
Force 12 Conditions
File S/M-39, obtained from Stephen Edwards & Deborah Schutz, Henley Beach, South Australia - Vessel name Prisana II, hailing port Adelaide, Tayana Surprise ketch, designed by Pieter Beeldsnidser, LOA 46' x LWL 40' x Beam 13' 4" x Draft 6' 10" x 13 Tons - Fin keel - Sea anchor: 18-ft. Diameter para-anchor (Para-Anchors Australia) on 410' x 3/4" nylon three strand rode with 3/4" stainless steel swivel - Partial trip-line - Deployed in a storm in deep water about 75 miles west of Cape Bouvard (Western Australia), with winds of 65-80 knots and seas of 40-60 feet, with microbursts evident - Vessel's bow yawed 20-30° during 59 hours at sea anchor. Drift was affected by a southerly current.
This important file was initially forwarded by Alby McCracken of Para-Anchors Australia, to whom we are indebted. The sea anchor used was 18 feet in diameter, manufactured by Para-Anchors Australia. Stephen Edwards and Deborah Schutz are quite certain that it saved the boat. The winter storm that they ran into may have been reinforced by microbursts, judging by the thunderstorm activity, and by the tornado that left a 2-mile long swath of destruction through South Perth.
Deborah Schutz was kind enough to send a clipping from the July 17, 1996 edition of The West Australian. The headline reads "South Perth Hit by Rare Tornado." Accompanying photographs show the twister's fury as it rampaged through South Perth, taking roofs off of houses and uprooting trees. The Australian Weather Bureau's severe weather meteorologist, Tony Bannister, said the tornado probably originated west of Rottnest Island, traveling at about 80 km/h at sea, increasing in intensity and sporting 200 km/h winds when touching down at Perth.
Prisana II is heavy, with a lot of windage - two equal height masts, both with in-mast furling. She was en route to Dampier, Western Australia, from her home port of Adelaide, South Australia, when she ran into this freak storm.
Perhaps we have a recurrence of the same sort of freak events that Gold Eagle ran into in File S/T-15, where we find Dr. Andrew Cserny writing, "Sometime during the night we were hit by an immensely strong burst of wind which I presumed must have been a twister, because the pressure inside the pilot house fluctuated rapidly, the windows rattled, the doors to the pilot house rattled, and the sliding hatches tried to come off the top of the boat.... The wind shrieked horribly with pitch and intensity I have never heard before." Gold Eagle was later struck by a rogue wave. So was Prisana II, leading your authors to believe that these may have been microburst-generated ESWs - extreme storm waves. Transcript:
Sunday July 14th, 1996: By nightfall we were almost abeam Cape Naturaliste. Our weather fax showed a complex low was fast approaching. Due to our position, the unfamiliar coastline and the wind direction (40 knots NNE) there were no safe anchorage along the coast here in these conditions. Our motor was playing up and the option of using our sea anchor already considered, but due to the number of ships in the vicinity, we decided to keep going. We reduced sails, expecting the winds to swing SW with the approaching front, which we'd use to get us to Fremantle. We were wrong! Throughout the night Mother Nature unleashed a storm of unrelenting fury, NNE to 50 knots with large seas - our only choice to head out to sea [starboard tack].
Monday July 15th: At first light we came about [port tack]. Perth Radio issued another gale force warning. The barometer read 996 and was rapidly falling. By evening strong west winds were in force, the barometer now at 990, though seas had moderated. As the night progressed, squalls reached 60 knots and lightning could be seen behind us as we traveled in a northerly direction [parallel to the coast of Western Australia]. The ferocity of the storm was intensifying. The needle on our wind indicator went beyond the last notch (65 knots) and the seas were dramatically increasing in height. At approximately 0500 hrs a huge wall of water knocked us down. The helmsman stood chest-high in water (thankfully harnessed) and our masts leaned to starboard, touching the surface of the ocean. We deployed the sea anchor, then all crew below and hatches battened. At this point we were 30 nautical miles off Rottnest Island.
Tuesday July 16th: During the morning I ventured above to the cockpit and was immediately awestruck. The seas were incredibly huge. I soon retreated below. I later found out the seas were reported to be 11 meters on top of a 9 meter swell - the faces of the waves around 60 feet. We currently had plenty of sea room and were drifting in a southerly direction at 1 knot. The parachute anchor held us steady, as the winds, sounding cyclonic, whirled over 70 knots. Waves drenched the deck as we rolled from side to side. For 24 hours we drifted in this direction, towards Naturaliste Reef.
Wednesday July 17th: We were drifting east and we now know that we were in the Leeuwin Current. The Leeuwin Current runs southward down the continental shelf from Indonesia, bringing masses of warm water. It begins flowing around April each year, through October, seldom moving faster than 1 knot in a band approximately 50 kilometers wide. The weather remained unchanged. All day long the winds continued to blow over 70 knots and we were now down almost as far as Bunbury, having crossed over, above the Naturaliste Reef. A large cargo ship had just lost 30 containers off Cape Leeuwin. The Adelaide media reported that a cyclone had hit Perth.
Thursday July 18th: Conditions were moderating, winds now down to 50 knots and the barometer slowly began to rise - seas still large but easing. Late in the afternoon we retrieved the para-anchor (which wasn't easy), and she came up with a hole in her. Our 130 meters of rope had stretched an extra 20 meters. The wind now blowing 30-40 knots - felt like a mere breeze as we set course for Rottnest Island. Friday July 19th, around 1030 hrs we motored into the Fremantle Sailing Club, grateful that we had decided to purchase a parachute anchor. With it we were able to ride out and survive the conditions - our bow held into the seas. The Weather Bureau in Perth described the freak weather as a rare winter tornado. It struck the coast with 200 km/h winds.
In the face of this important file, Victor Shane contacted Deborah Schutz & Stephen Edwards regarding a few more questions, and received additional answers as follows:
Was the deployment fairly easy? We preformed a "Flying Set" and deployment was relatively easy. The anchor rode was fixed to a strong point at our bow, led aft and held in position by plastic cable ties at 6-inch intervals along the port side toe rail to a deployment bag containing 125 meters of 18mm 3-strand nylon anchor rode. This was set up prior to our departure from Adelaide to cross the Great Australian Bight. Deployment simply involved reaching from the safety of the cockpit to the rode deployment bag, unlacing the top - removing the end of the rode and shackling it to the parachute anchor. Trip line floats were then fed overboard, followed by para-anchor in deployment bag. Within approximately 30 seconds, we had taken up all the rode and the vessel was gently pulled into the wind, allowing us to lower the sails.
How did the boat behave at sea anchor? Generally it appeared to be falling off 20 to 30 degrees, though it's difficult to be precise as we were below deck for nearly the whole duration of the storm. Occasionally we fell back on the rode and fell away to somewhere near 45°, approx. once every half hour, maybe due to rogue waves coming in on a different angle - hard to tell from down below.
What about the disposition of the rudder? The rudder was lashed to center at the quadrant, which broke twice - 6mm pre-stretched cord broke first, then 16mm nylon braid also didn't hold. We managed to make it hold on 18mm nylon anchor rode. Small twist, 10-15° in 2-inch 316 stainless steel rudder shaft at the point where quadrant is fixed.
What about chafe? Due to the set up of 1 meter of chain at the bow we had no chafing.
Any green water come on deck? Yes, Steve said there was a small amount, compared to the 2-3 foot of white water that washed over the deck.
General impressions of strains involved? We've realized the attachment point on bow needs to be extremely strong. Parachute anchor was shackled to 1/2 inch chain link welded to ship's anchor. Our ship's anchor was stored below deck level via custom bow fitting [as with large ships, the forward part of the anchor left protruding out of the bow, and the para-anchor rode shackled directly to the ship's anchor by a 1 meter length of chain], then secured aft by 3/8 inch Ronstan rigging screws, secured to a 10mm stainless steel plate, bolted under the anchor winch. Winch and plate fastened by 6 x 3/8 inch stainless steel studs. Both the fixing point to the ship's anchor and to the plate were backed up by secondary systems. Ronstan rigging screw had 10mm chain back-up. Fixing to anchor was backed up by 5/8 inch stainless steel bolt, through anchor cheeks. Both systems failed! Ronstan rigging screw had 8 turns of thread removed. Back-up held, but ship's anchor smashed around, causing damage to our stainless steel bow fitting. Chain-link welded to ship's anchor was torn off and secondary chain from nylon rode took up the weight on 5/8 inch stainless steel bolt through anchor cheeks.
Did you use a full trip line? No, partial trip line - 2 floats and 2 x 15 meter lines with swivels.
Was retrieval easy? Not really. Wind was still strong (40-45 knots) and seas were still huge and getting steeper due to the shallowing depths as we got close to the coast - running out of sea room. Due to the noise from the wind and seas it was difficult to hear skipper's instructions from the bow to the helm and we fouled the rode on the propeller.
How big was the tear in the para-anchor? Two large, well frayed holes in two separate panels, between the venthole and the skirt.
Did the para-anchor save the boat? Absolutely!!! In the conditions we were caught in, we believe having our para-anchor set up, ready for deployment prior to leaving port, was crucial in the safe and easy deployment. Seas were huge - by far the biggest we had ever seen. Parachute rode was spanning one swell, being ripped out of the troughs and pulled taut. There was much white water being swept from the swell tops - large rolling loads of white water. Prisana II took many loads of white water across the deck, (maybe 2-3 feet of white water coming over the bow). The conditions were so bad that it was impossible to be anywhere on deck. We used a harness just to visit the cockpit - almost all of our time was spent below deck. The noise of the wind whirling outside was incredible.
We had a close encounter with a container ship slowly jogging into the storm, headed our way on the dawn of day two. Our radio contact was first answered by another ship, Australian, six miles away, and they informed us that this container ship was a foreign vessel, also mentioning that they didn't envy us one bit. After ten long minutes the container ship finally answered our call and his broken English caused us a minor panic - he didn't seem eager to alter his course! He told us he had no ballast and that he couldn't even see us! After persuading him to alter course by 10-15 degrees he passed us by only 0.4 nautical miles away - confirmed by our radar. The seas were so big that we were totally losing sight of this container ship (approx 400 foot long with an extensive bridge structure) behind the swells.