sail-world.com
 
 
News Home Boats for Sale MarineBusiness-World Sail-World Racing Cruising Int Magnetic Is RW Photo Gallery FishingBoating
Sail-World.com : Carry this sailing navigation super tool for safety!
Carry this sailing navigation super tool for safety!


'Choose a navigation protractor that you find easy and intuitive to use for drawing courses or plotting bearings. I believe nothing tops the Weem’s plotter (lower plotting protractor) for simplicity, speed, accuracy, and practical sailing navigation in all sailing weather.'    Captain John Jamieson

In my mind, nothing beats simple and fast when it comes to plotting on a small sailboat. After all, you are short handed, on a heel, and want to spend minimum time in the cabin (if that's where you are plotting).

Enter the tool I use and have used for over two decades. And it comes not from the marine world--but that of the aviation world. I wouldn't sail without one or two aboard. Read on to discover this 'gotta-have-it' navigation magic tool!

I navigated big ships and small boats in the US Coast Guard in the days before push-button navigation. And navigation was anything but a relaxed environment as it often will be when sailing. Fixes in inland piloting waters were taken and plotted every one to three minutes, set and drift of current determined at each fix, course and speed to maintain track computed, and a recommendation given to the conning officer for new course, time to turn to next course, and so forth.

With ships drawing 12 to 17 feet (draft), there's not a lot of room for error. We needed fast, accurate, 'works-every-time' tools. You may have read my recommendation to use a drafting compass (also called a 'plotting compass') for most practical chart work in navigation. Matter of fact, I rarely ever use dividers except in the planning stages of a trip.

The same goes for parallel rules. I believe they are a challenge to use on any but the most stable of platforms. Take a bit of roll or pitch and they will often slip and slide, which can result in navigation errors of several degrees.

Line up the center crosshair (red arrow) with any vertical line or meridian on your nautical chart. Read the course or bearing direction where the vertical line intersects the half-circle. Take care to note the direction you want to travel (two directions are shown). -  Captain John Jamieson  
Do I use parallel rules? You bet--they make a great planning tool (before you depart), serve as a good straight edge, and are a superb backup tool in case your other tools break or fail. But they will never be my primary plotting tool.

Enter the Weem's plotter. This tool was first used by aircraft navigators. The Weems looks like a clear rectangular shaped protractor with a small bar on rollers attached to the bottom. The wheels enable you to roll the protractor across any flat surface.

An engraved half circle with a cross-hair has been placed in the center. Degrees on the outside of the half circle are for directions from north through east to south.

Degrees on the inside of the half circle are for directions from south through west and back up to north. Quarter circles are engraved at each end to use with parallels of latitude if desired (rarely used, but nice to have).

The top edge has convenient distance scales that can be used on three common coastal and harbor chart scales : 1:80,000; 1:40,000 and 1:20,000.

Follow these easy steps along with the illustrations to learn how to use the Weems plotter. Five minutes of practice and you will be a pro with this super navigation tool for sailing!

1. Draw the course line with the Weems onto your nautical chart. Or, you can skip this step if you want to plot a specific pre-determined course or bearing (illustrations). Go to step 2.

2. Roll the Weems over to any convenient vertical line nearby (use a meridian of longitude or other vertical line).

3. Line up the center cross-hair of the half circle with the line.

4. Read the direction where the vertical line crosses the half circle. Notice that each direction will be a reciprocal of the other. Take care to read the direction you are going.

Look at the illustrations and note that the vertical line intersects the Weem's half circle at 110° and 290° (the reciprocal). If you are sailing to the southeast your course will be 110°. If you are sailing to the northwest your course will be 290°. Use this same logic when taking bearings to prominent objects ashore or afloat.

5. You can also use the Weems plotter to determine the direction of a pre-plotted course line. Lay one part of the straight edge along the line. Slide the Weems over to any convenient vertical line. Read the instrument as described in the steps above.

How to Use the Weems Plotter with a Compass Rose
You may prefer to continue to use compass roses. Use the Weems and you will slice 50% or more off your plotting time compared to parallel rules. Line up the long edge of your Weems with a plotted course line. Slide the Weems over to the closest compass rose. Read the direction indicated on the compass rose (use the same cautions described earlier to be sure you read the correct direction).

Or, to start with the compass rose and find direction, line up the straight edge of the Weems with the center cross hair on the compass rose. Read the direction on the compass rose. Roll the Weems over to the departure point, draw the new course line and label with the direction.

What are the drawbacks?
The Weems was not built in a robust fashion. The plastic protractor part may seem a bit flimsy. And, you want to store it out of direct sunlight to prevent warping. I made a simple case for mine out of scrap cardboard. Cut two rectangular pieces two inches larger than the instrument all around. Use packing or wrapping tape on the long edges and one short edge. You can now insert the Weems into the case to protect it when packing for a trip or aboard your boat.

Boost your sailing navigation accuracy with the power of the Weems plotting protractor. This will give you the confidence to navigate your small sailboat faster and easier--wherever in the world you choose to sail or cruise!

John Jamieson (Captain John) with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website at website! Sign up for the Free, highly
popular weekly 'Captain John's Sailing Tip-of-the-Week'. Discover how you can gain instant access to hundreds of sailing articles, videos, and e-Books!


by John Jamieson

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=111609

1:59 PM Fri 5 Jul 2013GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.







Sail-World Cruising News - local and the World



Canal Boating in the Alsace with the Galley Guys by Greg Nicoll with John Armstrong,




World ARC fleet arrives in Darwin by World Cruising Club,






Dangers of the Dinghy trip back to your boat by Rob Kothe & the Sail-World Team,






Where in the world are our strongest corals? by Hanny Rivera - Cohen's Lab,






Barnacle Busting by Neil and Ley Langford,




Polar research: Six priorities for Antarctic science by Mahlon C. Kennicutt II and colleagues,




































Risks to penguin populations continues by British Antarctic Survey,


Dangerous conditions for boaters from this afternoon
ARC Baltic fleet head from Helsinki to Stockholm
Follow these tips when anchoring
Swedish couple rescued off Cook Islands
Elaine Fowler, RPAYC's first female life member elected
Refurbished Protector project 'better than buying new'
Galley Guys meet the Spice Lady
Discover science of maritime exploration at National Maritime Museum
Royal Prince Alfred Yacht Club’s Jack Gale training centre born
Multihull Central launches Aquila range at SIBS *Feature
If all else fails read the instructions!!
ARC Baltic fleet cruising and anchoring in the Finnish archipelago
Phuket Yacht Show: new kid on the block taking on PIMEX? *Feature
Endangered species are like Movie Stars - Charlie Sheens and Tom Hanks
Vanuatu Customs making life easier for visiting cruising yachts
Multihull Central - Covering all the bases *Feature
Baltic 4 Nations rally is now in full swing
Flags at Sea, an infographic by John Tissott
Cruising lessons from ocean racers
Sydney International Boat Show - Day 2 *Feature
Marine Rescue volunteers celebrate new unit and $120,000 vessel   
Procedures set out for waterborne visitors to Vanuatu   
17-year-old RNLI volunteer saves child in first rescue mission + Video   
Teen names latest RNLI Shannon class lifeboat in Poole + Video   
Fascinating opportunity with OceansWatch   
Pantaenius Insurance - being seen in yellow, green and orange *Feature   
Fake GPS signals detected when cruising the high seas   
Sydney International Boat Show - Changed conditions on Sydney Harbour   
Our new Cruising Editor editor remembers his first offshore adventure   
World Odyssey Race - Bringing back the Corinthian spirit   
Blue Planet Odyssey Rally - Raising climate change awareness   
Pacific Circuit Rally - 2015   
All Points Rally departs this November   
Gold Coast Broadwater no closer to welcoming supermaxis *Feature   
2014 Magnetic Island Race Week Cruising North - One for Poppy? *Feature   
World ARC 2014 reaches Australia   
A Mooring in Iceberg Alley   
Marine Rescue volunteers called to rescue out of fuel vessel updates   
Marine Rescue volunteers called to rescue second vessel out of fuel   
Boaters urged to speak up on 15%ethanol proposal   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph, contact the photographer directly.
XLXL WAS Cru SH
LocalAds   DE  ES  FR  IT