Short Tacks - Ocean Navigator

31 Dec

Weather models and GRIB files

Peter IslerShort Tacks, Weather

Weather models and their digitized end product, the GRIB file, are key facets of weather forecasting. An understanding of these elements will help any voyaging sailor to better decipher the weather. When I was in college, I was primarily a dinghy sailor and was just getting started in offshore navigation and race tactics. I knew how to read a weather map and listen to the marine forecast on the VHF radio, but beyond that I just took what Mother Nature gave me. In college, I majored in meteorology since it was the closest subject I could find to my favorite…

31 Oct

The Transpac Race: A legacy of teamwork

Story and photos by Craig SmithShort Tacks, Transpac Race

Editor’s note: Ocean Navigator was a co-sponsor of the 2021 Transpac. Below is a story detailing one crew’s experience from the race. When sailor David Dahl and his two sons, Michael and Sean, started the 2021 Transpac Race aboard the Andrews 77 Compadres, they were taking part in and extending a company tradition that goes back to 1923. Dahl is the CEO of Whittier Trust in South Pasadena, Calif. Ninety-eight years ago the company founder, Max Whittier, purchased the 107-foot yacht Poinsettia and entered the race with his three sons in the crew. “You realize at 1,100 miles offshore, you…

01 Sep

Timing the tides

Ocean NavigatorShort Tackscoastal navigation, Fire Island, Great South Bay, high tide, International Folkboat, low tide, marine tides, New York Harbor, NOAA, NOAA tide charts, passage planning, tidal current tables, tides

Navigation is fundamentally about discovering the rules that govern nature. Unlocking these secrets is one of the most gratifying aspects of sailing; from observing the physics of weather to revealing our position relative to the celestial bodies. Another one of the most rewarding elements of navigation is understanding the tides. And tide considerations became central to the planning of a recent 60-nm passage I made in late summer of 2020 from the Great South Bay on Long Island to New York Harbor. Tides express themselves in two distinct but subtly interrelated ways: vertically through tidal height and horizontally through tidal currents.…

01 Jan

A racer's perspective on climbing the mast

Ocean NavigatorShort Tacks

As a racing sailor, the recent article on how voyaging sailors should climb a mast ("Climbing the mast," July/August 2000, Issue No. 107) grabbed my attention, and I thought readers might like to hear how racers handled this task. Racers discarded bosun's chairs long ago. I have been using a mountain-climbing harness for 30 years. The recent article does not mention the most important features of a climbing harness as contrasted with a bosun's chair. First, with a climbing harness, you can actually climb the mast, with the halyard(s) being merely an assist. The point is that, with a climbing…

01 Jan

More on mariners' anti-malaria measures

Ocean NavigatorShort Tacks

Your recent article on malaria ("Malaria prevention," Issue No. 90) has a few errors and omissions that this retired preventive medicine type noted. First, permethrin is more toxic than DEET, not less. It is actually an insecticide (of the pyrethroid class), not just a repellent, with some uses for killing lice. Uncle Sam's Army says never put it on the skin, just on the outer clothing. It does have the advantage that it is still effective after several washings. Also, way back when, we named WR-142,490 "mefloquine," with a terminal "e." On a more serious note, if you are going…

01 Jan

Nada's re-rigging: finally getting it right

Ocean NavigatorNavigation, Short Tacks

Recently we converted our wooden-sparred ketch Nada to an aluminum-sparred cutter. The idea was to remove weight aloft from what had always been an overly tender boat. However, I didn't get things quite right when I calculated the new location of the mast. It turned out that I moved it too far aft, giving Nada excessive weather helm. We have a relatively small main (303 square feet), and a relatively large genoa (550 square feet), but, even so, any time we set the full main it completely overpowered the headsails and Nada simply rounded up. The boat did so with…

01 Jan

House sail' shades southeast glass wall

Ocean NavigatorShort Tacks

To the editor: I would like to offer a more seaman-like solution than pasting up paper to screen your handsome new offices from the sun (Chartroom Chatter, Issue 119, Jan.⁄Feb. 2002). I had a similar problem several years ago with the morning sun flooding a two-story living room that presented a glass wall to the southeast. Furniture, floor and paintings were fried, and I was determined to find a better solution than turning the entire room beige or blocking the view with a cat's cradle of curtains and drawstrings. So I sunk four stainless steel eyes in the four corners…

01 Jan

Don't forget to put your boat aground

Ocean NavigatorShort Tacks

The recent article by Gordon Wyatt on antennas ("Homemade antenna," Issue No. 90) was very interesting and practical. However, no mention was made of the fact that a proper grounding or counterpoise system must be included with all HF long-wire or insulated backstay installations. In fact, a proper seawater ground is the key to good performance. As mentioned in the article, the antenna coupler will match the 50-ohm output impedance of the transceiver to the long wire, but only if a ground is attached to the coupler. I have experimented with such antennas for the past 20 years and have…

01 Jan

Offshore telemedicine services explained

Ocean NavigatorGood Reads, Short Tacks

From Ocean Navigator #99 July/August 1999 To the editor: Thank you for summarizing the services of the Maritime Health Services Division of Global Medical Systems, Inc. (MHS), in the recent story by William Boyd on telemedicine ("Doctor on Call," Issue No. 97, Ocean Voyager). There are just a few points that I wish to mention. In the text, MHS is referred to as a subsidiary of AEA International. As of June 1998 MHS has been independent of AEA International but has maintained full access to the services of this leading provider of international medical assistance. Dr. Brown and I now…

01 Jan

Searching for Slocum's clock

Ocean NavigatorShort Tacks

To the editor: “At Yarmouth, too, I got my famous tin clock, the only timepiece I carried on the whole voyage. The price of it was a dollar and a half, but on account of the face being smashed the merchant let me have it for a dollar,” so says Joshua Slocum in Sailing Alone Around the World. Slocum’s well-known volume whimsically chronicles his three-year voyage, the first solo circumnavigation, between 1895 and 1899. He met famous people and fought off cannibals. He weathered storms, sickness, calms and hallucinations. But of all the interesting and telling parts of his fascinating…