Wednesday, October 03, 2012

Sunset Regatta (5a): A case study in racing risks and seamanship; Tanzer 7.5 sloop gets stuck on a shoal... and then unstuck

Sailboat racing has many hazards and risks, and sometimes racers take calculated risks in order to gain time and distance in a race. When you combine this with a lake that was just beginning to recover from its lowest water levels in eight years, with a resulting much shallower average depth than usual and shoals in unaccustomed locations, and hold a long-distance race in areas where people don't sail so often, you get a recipe for the risk of grounding (or "allisions"). In fact, three of the Sunset Regatta boats did just that, but one was able to get ungrounded via muscle power only. This series shows what happened to a 24-foot Tanzer 7.5 sloop.

Tanzer 7.5 approaching the mark. Government mark no. 7, near the southern end of Elephant Butte Lake in southern New Mexico, was the turning mark for the Sunset Regatta and was also a marker for the north/northwest (port) side of a safe water channel leading from Elephant Butte Dam and the DamSite Marina northward up to the main body of the lake. About 200 feet to the north/northeast of it was a hazard marker buoy. (4084) (15:19:34 approx. time by camera time stamp, which may have some error)

Tanzer aground! Winds are very switchy and fickle and the vicinity of the "Elephant" formation that gives the lake and community its name. A southwesterly breeze that was blowing at three or four knots meant that boats coming from the upchannel were favored to be on port tack, and the Tanzer's line took her between the hazard mark and channel marker, but closer to the hazard mark. Staying inside the line of the channel markers would have meant taking two or more extra tacks and sailing extra distance, generally a no-no to racers. (4087) (15:24:38)

Tanzer 7.5 on the dirt. Also, most Elephant Butte Lake sailors are accustomed to the lake when it is at a higher level and has fewer shoals, particularly in cases where a boat is well away from the shoreline. Here, this proved to be a poor guide, as shoals appeared in the form of underwater ridges and hillocks well away from the visible shoreline. Exploring in the power boat, we later found shallow areas halfway from the hazard mark to the channel mark. In fact, the hazard marker only identified a general vicinity of hazards, which according to the park service could be within a hundred yards of the marker. That's tricky when the channel marker, which represents deep, safe water anywhere within its swinging radius, is much less than a hundreds yards from the hazard marker. (4090) (15:25:42)

Tanzer 7.5 near hazard buoy. After starting the race and watching the fleet head southward, we had remained on anchor until all the boats disappeared south past Rattlesnake Island -- which has been a peninsula for the past year and more due to low lake levels. In addition to getting more pictures of race boats, our purpose was to provide some security and safety in case any boats or sailors got in serious trouble. We could also provide a progress report to people on shore about the progress of the race. Also, by observing the mark rounding at the far end of the course, we would be in position to shorten the race if the wind had failed totally, and then probably help tow one or more motorless boats back to the marina if needed. Fortunately, the winds did mostly improve as the race progressed. (4091) (15:26:12)

Out on a limb. Tanzer's crew puts weight on the swung-out boom to heel the boat, thereby reducing its draft, while the skipper gets off the boat on the shallow side of the shoal to push and rock and rotate the boat off the mud. A previous attempt at kedging -- throwing an anchor into deeper water -- had not been successful because of steeply sloping bottom contours with depth dropping off from about four feet to more than twenty within perhaps a few boat lengths. (4096) (15:27:44)

Heeling the Tanzer. Under the current version of the racing rules, a crew may use any form of muscle power to un-ground a boat and return to racing. But, the use of a motor would normally disqualify a boat from continuing to race. (In the 2013-2016 version of the rules, sailboat race organizers will have the option of modifying the rules so that a motor can be used to get a boat unstuck, provided the boat doesn't get any advantage in moving down the course... but that's not yet available.) So, the crew was motivated to get their boat off the mud by whatever use of muscle power might work. (4097) (15:27:50)

Heeling the Tanzer, with hazard buoy visible nearby. In extremis, a crew could, after muscle-powered attempts failed, turn to using their motor, or being towed off by another boat, such as our boat that was being used a committee boat or a state parks patrol boat. However, our boat had a deep enough draft and was unable to use reverse gear because of a problem we had that weekend with the gear shift cable in the engine compartment, so we would have had to throw or float a long line to a boat from a distance in order to tow. (4098) (15:27:56)

Tanzer heeling. Most of the sailboat racing at Elephant Butte Lake occurs in the central basin of the lake, which is a few miles north of the area near the "Elephant". Hence, some of the skippers participating in the regatta had never been in this part of the lake with the lake level this low. (4099) (15:28:02)

Tanzer 7.5 maybe beginning to pivot and move off the shoal? (4100) (15:28:14)

Skipper pivoting Tanzer and moving the boat at the bow (4101) (15:28:36)

Dan and I got off the shoal by doing just what you can see in the pic. We tried putting all our weight to one side, backwinding sails (wind was from the wrong direction for that), etc. and still couldn't get her off so Dan went out on the boom over the water and I went in the lake to find that shoal to stand on and was able to shove the boat off the side of the shoal and climb back aboard via the stern ladder. Dan hoisted sails (the spinnaker this time) and we were off again on the downwind leg! What a great day of sailing! :)

Pushing the Tanzer off the shoal (4102) (15:28:42)

Moving toward deeper water (4103) (15:29:00)

Tanzer sailing off the shoal! (4106) (15:30:30)
Aftermath: The Tanzer and crew were able to continue in the race, after losing perhaps about seven minutes to the grounding, but were able to earn a trophy finish in the race, correcting their finish on time over that of most of the fleet. The bottom appeared to have been soft, and winds were light at the time, so it is unlikely that any damage was done to the boat other than perhaps some minor scratches.
Of course, groundings can be far worse and are not something that any sailor enjoys.
That applies to BOTH kinds of sailors: Those who HAVE grounded and those who WILL ground.

(Perhaps a few have prevaricated about having grounded!
Or perhaps a few are like the so-called "Old Salt" who told his passengers, "I knew every reef and shoal in this bay."
"Boom!! Crunch!"
"See, there's another one!" ).

Snug lines, sail well.


At 10:44 AM, October 10, 2012, Blogger Tillerman said...

Thank you for giving me another reason to be thankful I sail a Laser!


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