Cruising Tips - Navigation

Chart Smart (July 2006)We arrived off Suva, the capital of Fiji, after a 10-day passage from New Zealand. While we knew the island of Viti Levu was about 5 miles off our bow, we couldn’t see it because of a heavy rainstorm. My husband, Bob, turned on the computer and looked at the electronic charts we had added to our navigation suite a few weeks earlier. We wanted to use them to
Author:
Publish date:

Chart Smart (July 2006)

We arrived off Suva, the capital of Fiji, after a 10-day passage from New Zealand. While we knew the island of Viti Levu was about 5 miles off our bow, we couldn’t see it because of a heavy rainstorm. My husband, Bob, turned on the computer and looked at the electronic charts we had added to our navigation suite a few weeks earlier. We wanted to use them to help us get through the pass in the reef but were unwilling to trust them, knowing charts are often inaccurate in this part of the world.

We hove-to, hoping the visibility would improve, after two hours we concluded conditions weren’t going to change quickly. We got on the radio and called boats we knew were already anchored in the harbor. We asked whether they had used electronic charts to get through the pass and, if so, whether the data was spot-on. After we heard from three boats whose judgment we trusted, we felt better about the accuracy of our charts.

As we went in, we kept our paper charts laid out with the route carefully plotted; I stood watch on the bow. We motored through the rain at a snail’s pace and used the radar and depthsounder to keep track of our location. We had no problems, and everything worked out fine—including the electronic charts. But the moral of the story is that you never should rely on just one form of position finding. Even though electronic charts can guide you through potentially hazardous waters, you should always use as many different sources of position data as you can and constantly evaluate all of them as you check and double-check your position. You—not the equipment—are responsible for your navigation decisions. Cary Deringer

Radar piloting (June 2006)

The most accurate tool for estimating your distance to a solid target is radar. When you have to traverse a narrow channel close to the shore with off-lying dangers and you can’t line up two objects to see you through, select the most appropriate range setting, then set the variable range marker (VRM) to a safe distance from whichever shore seems likely to offer the best radar target. You can then sail or motor along and be sure of your distance off. Double-check everything, make sure you have a bailout plan in case the radar goes on the blink, then forge ahead while keeping the VRM just touching the echo of the shore. Tom Cunliffe

GPS and Great-circle Courses for Ocean Navigators (March 2006)

Most GPS receivers are capable of delivering the bearing to a waypoint as either a rhumb-line or a great-circle course. When sailing along the coast or making an offshore passage, the two are synonymous for all practical purposes. However, when making an east-west ocean passage well away from the equator, following a great-circle course—so far as wind and wave permit—could save a day or more. Thanks to your GPS, you need not immerse yourself in tortuous calculations involving spherical trigonometry or plot new courses repeatedly from a gnomonic chart. As long as you have specified great-circle course on the setup page, you have only to create a destination waypoint, hit the go-to button, and read off the course. The figure you get will be the great-circle heading from your current position. Tom Cunliffe

Click here to return to the Cruising Tips Archive

Related

arc18-3981

Stories from the Cruisers of the ARC

Each December, the docks at Rodney Bay Marina in St. Lucia are abuzz as the fleet of the ARC—the Atlantic Rally for Cruisers—arrives to much fanfare. No matter what time of day or night, the staff of the World Cruising Club, organizers of the 33-year-old rally, are there to ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com A sign from outside the box  Rev counters on modern engines are driven electronically from a terminal on the alternator. If all is well, as soon as the engine fires up the revs will read true. If, ...read more

emSelf-tacking-jib

Ask Sail: Are Self-trackers Worth It?

Q: I’m seeing more and more self-tacking jibs out on the water (and in the pages of SAIL) these days. I can’t help thinking these boats are all hopelessly underpowered, especially off the wind, when compared to boats with even slightly overlapping headsails. But I could be ...read more

01-LEAD-hose-leak-CREDIT-BoatUS

Know how: Is Your Bilge Pump up to the Job?

Without much reflection, I recently replaced my broken bilge pump with a slightly larger model. After all, I thought, surely an 800 gallon-per-hour (gph) pump will outperform the previous 500gph unit? Well, yes, but that’s no reason to feel much safer, as I soon discovered. The ...read more

190314-viddy

St. Maarten Heineken Regatta: A Source of Hope

The tagline for the St. Maarten Heineken Regatta is "serious sailing, serious fun." However, for the inhabitants of St. Maarten, the event is more than just a festival of great music and some of the best sailing around. Local blogger Angie Soeffker explains the impact the race ...read more

SPOTX-1500x1500_front

Gear: SPOT-X Satellite

Hits the SPOT The SPOT-X two-way satellite messenger is an economical way of staying connected to the outside world via text or e-mail when you’re at sea. As well as the messaging service, it has a distress function that not only alerts authorities if you’re in trouble, but lets ...read more

_8105684

A Kid’s Take on the Northwest Passage

Going North—and West Crack! Crunch! I woke with a start to the sound of ice scraping the hull of our 60ft sailboat, Dogbark. In a drowsy daze, I hobbled out of the small cabin I was sharing with my little sister. As I emerged into the cockpit, I swiveled my head, searching for ...read more