The line itself is not needed. It is easier to convert time zones. The Marshall Islands are Zone  +12. Baker Island is Zone -12.   To go east from +12 to -12 there is a total change of -24.

That results in setting the calendar back 1 day and gaining 1 day when going eastward.  In the opposite direction from -12 to +12 there is a total change of +24. That results in setting the calendar ahead 1 day and losing a day when going westward.  

Suppose it is 1 pm in San Diego (Zone -8) on Monday. You want to know the date and time in the Kiribati Line Islands (Zone +14). Do the time zone conversion and the date will follow. From -8 to +14 is a change of +22.  So add 22 to 1 pm. Do this in 2 steps. Add 11 hours to get to midnight and thus the next day, Tuesday. Then add 11 more hours to get to 11 am on Tuesday. 

Before the date line change, the Kiribati Line Islands were in Zone -10.  From -8 to -10 would have been a reduction of 2 hours from 1 pm to 11 am on Monday.

Wikipedia points out that it is possible to simultaneously have three different dates in the world. This is because of the bending of the so-called date line. The best method to calculate is again by time zone difference while forgetting about date line. 

Calculate as follows:

Start with 10:01 am on Thursday at UTC (Zone 0, Greenwich, England).
Find time in American Samoa (Zone -11).  From 0 to -11 is a change of -11 which is 11:01 pm Wednesday because in subtracting 11 hours from 10:01 am, we pass backwards over midnight. 

Find time in Kiribati, Line Islands (+14). From 0 to +14 is a change of +14 which is 12:01 am Friday because in adding 14 hours we pass forward over midnight.
See “Facts dependent on the IDL” section of Wikipedia, International Date Line
 
Here are some steps to keep things straight when converting between time zones:

• Remove daylight savings (subtract 1 hour, “fall back”) wherever used.
• Calculate hour difference between time zones (see examples above).
• The dates will adjust automatically with correct math.
• Add daylight saving back if applicable (add 1 hour, “spring forward”).

​Click here for a 2 page chart. 
Page 1 permits calculations by table. Page 2 gives examples of time zones.

Example calculation: 
Convert April 29 at 5:01 pm San Diego to Fiji date and time. Look on page 2 and see that San Diego is Zone -8 (U) and Fiji is Zone +12 (M). Start with 5:01 pm DST and subtract  1 hour to get 4:01 pm standard time. Add 12 hours for 24 hour time of 1601. Find 16 in column for zone -8 (U). It is marked as 16- in pink to show it is a day behind UTC which means UTC is a day ahead of it. 

Look to right in UTC column and see it is “00 midnight.” Therefore April 29 at 5:01 pm DST in San Diego is April 30 at 0001 UTC. Keep in this same time row going right to the column of +12 (M) Fiji and find 12. Therefore Fiji in standard time is 1201 or 12:01 pm. Look on Page 2 to see that Fiji is below the equator (lat. 17 deg. s) so it has winter when San Diego has summer. 

Internet search confirms hunch that Fiji does not have Daylight Savings Time on April 30, so the answer remains as 12:01 pm on April 30. Internet confirms this is correct, but no internet or computer is needed with the 2-page chart available here for printing with the permission of author. 

Consider again the 10:01 am example shown by Wikipedia when there are three dates in the world at the same instant. This can be seen on Page 1 of the above chart by looking at 10 am UTC and noting that at that time it is 1 day earlier (pink 23-) in Zone -11 (X) and 1 day later (yellow 00+) in Zone +14 (M †). This only happens because of the new times zones +13 and +14. 

The result is that the date line is no longer as simple as adding or subtracting 1 day.  If it were 11:01 pm in America Samoa (Zone -11),  and you were able to jump in 10 minutes to Kiribati  (Zone +14), your watch would read 11:11 pm. Then you would need to advance your watch and calendar by 25 hours putting you at the hour of 11 minutes after midnight two days later.  One day for the movement past midnight and 1 day because Kiribati advanced itself ahead a day from what would be expected by a normal date line. 

​Accordingly, the International Date Line is none of the three things implied by its name. It is not international because time is decided by local politics. It is not a single date change because in theory there could be a 2-day change when crossing. It is not a line because it zigs and zags and potentially could be discontinuous according to the whim of localities. But you still must change your ship’s calendar at some point when circumnavigating the globe.

ADDENDUM TO MEASURING TIME

Mathematician David Darling explains  “there’s no way to continuously map points on a real number line onto a circle” as shown by “the “Borsuk-Ulam theorem in one dimension.”  “The International Date Line is needed ... (because it) takes care of the inevitable discontinuity by having it happen all at once, as a jump by one whole day, on a longitude that passes mostly through open water in the Pacific.”  The Universal Book of Mathematics: From Abracadabra to Zeno's Paradoxes by David Darling.  

Here is a video explanation of that theorem. The part about temperature (single dimension) is relevant. The video shows that on an instantaneous trip about the equator, assuming that temperature change from point to point is continuous, then there must be two antipodal points with the same temperature. 

Two antipodal points are defined as diametrically opposed points which means points connected by a diameter which means points connected by a line running through the center of the earth. 

I would welcome any reader to check and expand my following understanding of the above. We want two things from our time system: 

1. Time to flow continuously as it does on a real number line from starting point to infinity with possibility for an infinite number of ever smaller divisions of measurement between points of that line. 
2. Time zones to be rationally related with neighboring time zones so as to

• progress between time zones with equal time increments and 
• keep to the convention of clock noon fitting with sun noon. 

These two wants create a continuity which can not work on a circle in which any circumnavigation starts and ends at the same point of a circle. A discontinuity must be introduced. The Time Line does so.

While there must be a discontinuity, it need not be a line drawn on the map. The system of times zones flowing as +1, +2 to +12 in one direction from the Prime Meridian and -1, -2, to -12 in the other direction automatically create the necessary discontinuity. Movement between the neighboring  -12 and +12 zones creates a discontinuity of a time zone change of 24 hours. 

In all other movements between time zones the time zone change is 1 hour. We could go to 48 zones of 30 minutes each with -24 and +24 as neighbors. There  would still be a difference between these discontinuous neighbors equal to 48 times 30/60 which is still 24 hours. Or go to times zones as small as you like and the discontinuity would still be handled as 1 day of 24 hours.

USE UTC

We need agreement on time to navigate and coordinate activities including rescues. See UTC as a great convenience and safety mechanism rather than an irritating strange number for converting to local time. Ships should keep a clock set to UTC or at least keep in their log the difference between their current settings of GPS devices, watches, clocks etc. and UTC. There is possibility of trying to have extra safety with several GPS devices, but they are all inadvertently programed for different local times.

HAVE A MEANS TO ALWAYS KNOW UTC

There is no other way to assure coordination between you and the world outside your ship whether that be a rescuer or  navigation by celestial objects. UTC is simple. Everyone agrees on what it is. It flows second by second in only one direction. There are no time zone shifts and no date shifts to make mistakes with.

Local time can take care of itself. When you stop on an island, you can ask locals what they are using for date and the time. For all you know they might have changed their clocks and date by a new law passed while you were at sea. If you lose track of UTC, that could be a big problem. You do not really need to know local time until you are catching an airplane home. Then you can ask.

WHAT IS UTC?

UTC stands for Coordinated Universal Time. It is our primary time standard, not a time zone. It happens that when people in Greenwich, England are not using Daylight Savings Time, then their time zone (0 or Z or Zulu or GMT) has the same time (as a practical matter) as UTC.  UTC gets adjusted by a second from time to time to coordinate with the sun. Other time standards may not do this so as to keep them simpler and more consistent. 

Time is always measured by repletion of cyclic events. The cycle of the earth’s rotation, the cycle of the moon, the ticking of a clock, the swing of a pendulum, the hum of a tuning fork. 

UTC is maintained by observing the resonance frequency of the cesium atom.

HOW TO USE UTC

​When you need to communicate with others about the world, coordinating your plans by UTC is the easiest way to avoid making a computational error. 
​
To convert to local time and date, add or subtract the local zone and then if applicable add 1 hour for daylight savings.

When seen about the time of sunrise, the moon is always waning and a quarter moon is always 3rd quarter. Whatever moon phase you see about the time of sunrise, you can be sure that at the next sunrise the moon will illuminate less area until it gets to new. 

This shows the range of possible moon phases at sunrise. ​

Sailing to Santa Cruz Island and going ashore to the Nature Conservancy’s private wilderness portion of the island is a privilege as well as a fabulous experience.

To take advantage of that privilege, Celtic Song must acquire a landing permit. All crew members must read it. You can do so now: 
 
Each person must also have obtained, printed, signed, copied, and returned The Nature Conservancy Acknowledgment, Release, and Indemnification form to the address on the landing permit. In addition to sending it, you must also keep a copy as proof. This becomes your “ticket,” and you won’t be allowed ashore unless you have it. 

Here is a summary for Celtic Song crew to help with — not replace — reading the form and its rules. This is not meant as advice, interpretation or a legal opinion. 

You could be injured or take ill in a way that could cost you your life or cost lifetime expenses for medical care. 

Some examples of specific dangers of this island in addition to the general dangers of going ashore from a sailboat to any island: 

• Steep cliffs, slippery rocks and soils, landslides. (People have died). 
• Rodents with diseases including hantavirus. Anyone who comes into contact with rodents that carry hantavirus is at risk of Hantavirus Pulmonary Syndrome or HPS, a severe, sometimes fatal, respiratory disease in humans caused by infection with a hantavirus.  
• Wild animals, mold, yellow jackets, bees, ticks.
• Falling branches. Example of fatality from tree in San Diego.  
• Cactus spines, poison oak, stinging nettles.
• Non-potable water.
• Unstable building structures.
  
  

The Nature Conservancy will not pay you anything if you are injured or killed on the SCI Preserve (release of liability) and you will reimburse it and those associated with it for claims made against them by others because of your actions on or about the SCI Preserve (indemnification).

SUMMARY OF RULES for use of the SCI Preserve. (Please read the actual rules). Remove dirt, seeds and insects from shoes etc. before arriving at island.

Prohibited Items: cardboard (because it can harbor insects), pets, plants, unprocessed wood, fireworks, firearms, weapons, bicycles.

​Prohibited Activities: 

• Leaving any of your stuff behind on the island. Examples: Orange peels or paper (unsightly), apple cores (seeds), plastic (environment).
• Collecting (taking) any of the island stuff such as flowers or rocks.
• Photography. Exception: Photography OK if:  
  • it is only of nature with no buildings or facilities shown  
  • it is for personal non-commercial use and  
  • it is not shared or published unless done with “appropriate restrictions which prohibit the commercial use of the images.”
• Entry to the central valley of the island including Christy Beach area at the west end of island and Canada del Puerto road located to the south of Prisoners’ Harbor at the east end of the preserve. See landing permit map.
• Fire, cooking, smoking (fire hazard). Note: Cooking onboard vessel is OK.
• Disturbing animals, fishing, hunting.
• Cutting vegetation.
• Entering into any structure (building).
• Camping

When I was 12, my father ordered a 30-foot Chris Craft cabin cruiser to be christened Jaunty June in honor of my mother who, as it happened, never much enjoyed life on a boat. 

For me the boat became a ticket to summer adventures from New York City to Maine by sea and to Canada by Hudson River, Lake Champlain, and upstate canals and locks. 

While waiting for his boat, my father nearly memorized Chapman’s Piloting & Seamanship  proudly telling me of his mental prowess and giving a lesson he was willing to share with his eager son: “East is least and west is best, un-correcting.” 
​
I always remembered, but never understood, what that meant until after his death when I studied navigation during the year Celtic Song was being built in Orange County.

Finding North by the North Star (Polaris) is easy. Look up in the night sky. The North Pole is located directly below Polaris. There lies North. 

This works in the Northern Hemisphere for the period from Shakespeare’s time through the 21st century. In 3,200 years, a new pole star will be needed because of the precession of the Earth’s axis (wobbling like a top).
See these links for reference:

1. Polaris
2. Precession
3. Polaris
4. Pole star

If you sail south from the Northern Hemisphere, night by night you will see the height of Polaris fall towards the horizon until it disappears as you pass over the equator. That’s what I saw on a voyage from Puerta Vallarta, Mexico to Hiva Oa of the Marquesas in French Polynesia. 

On any clear night in the Northern Hemisphere, you can estimate latitude by observing the angle of Polaris above the horizon. At 90 degrees, you are at the North Pole. At zero degrees, you are somewhere on the 24,901-mile equator.   

After you pass over the equator to the Southern Hemisphere, you find the South Pole by using the Southern Cross. You can research that and teach it to me.

​When you know where north is, you can hold a circle of directions (known as rose of the winds or compass rose) parallel to the sea with the line marked north pointing to north so that by looking at the circle you can see which way lies every other direction (east, south, west).

In the accompanying compass rose that I created for Celtic Song, 112.5 degrees represents the angle in which the green starboard navigation light shines from dead ahead to “two points abaft the starboard beam.”  With 32 points in 360 degrees, each point is 11.25 degrees. Starting from dead ahead, the starboard beam sits at 90 degrees. Two points more add 22.5 degrees giving an angle of 112.5 degrees. Today the COLREGS use the phrase “22.5 degrees” in nine places.

Why an angle in fractional degrees? Because the rule’s angle remains constant while the unit of measurement has changed from points to degrees. Also, after subtracting 112.5 degrees on starboard and 112.5 on port, 135 degrees remain across the stern. This is the angle of white stern light. It is the angle an approaching vessel is, under the COLREGS, an overtaking vessel.

​I always keep the Celtic Song compass rose on the navigation desk to help translate a bearing from a number of degrees (as received from the AIS) to a graphic bearing line on the chart plotter or on a paper chart. 

​The AIS is True North Up; it gives bearings in True only -- not magnetic. So for consistency, the chart plotter at the Nav Station must stay set for True North Up. Paper charts are also True North Up. ​

Let’s focus on a portion of the world shown in the upper right.

The magnetic 12 east variation line (red thin above red bold) runs approximately through San Diego and the Aleutian Islands. The 20 east variation line (red bold) touches down to the Gulf of Alaska north of Glacier Bay. The zero variation line (green) cuts through the Midwest of the U.S. running into the Gulf of Mexico at about New Orleans. The 10 west variation line (-10 blue bold) cuts into the Eastern Seaboard in the Mid Atlantic states.

Now let’s go from the big picture to greater precision. What was the magnetic variation of the Harbor Island Fuel Dock on Jan. 1, 2017?  Three methods for answering:
(1) Paper chart.
(2) Calculation from model using a web site 
(3) Computer software

For the paper chart method, start with the correct chart:​

Look at the portion of its compass rose (upper right) where it says: VAR 12°00’ E (2012) Annual Decrease 6’

In about 5 years, at 6 minutes of angle a year, the decrease is 30 minutes of angle — 30 divided by 60 or 0.5 degrees of angle. So the variation in San Diego on Jan. 1, 2017 is about 12 degrees East minus 0.5 degrees East or 11.5 degrees East.

​For the calculation from model method, start with this web site:

Enter latitude and longitude of Harbor Island fuel dock and date of Jan. 1, 2017 and receive the answer of “2017-01-01, 11.61° E  ± 0.33°” using the year 2015 World Magnetic Model. 

​Or get the world declination software and make the calculation without an internet connection.

​The result is the same. Remember that positive declination is East Variation and negative declination is West Variation.​

No small boat should cross an ocean without one or more crew members trained as medical officer. 

This is different from basic CPR or the first aid training of the 3 Cs: Check, Call 911, Care until ambulance arrives. At sea, you are the ambulance and the hospital. That extraordinary responsibility requires bravura mixed with humility. 

Fortunately, excellent training is available. The cool result of training is getting to correct thinking. That means knowing you can do much more to help than you might have imagined. 

​Correct thinking also means knowing you can do much less to help than you might have wished. The resolution of this paradox is learning to distinguish one from the other. The process is a journey into medicine and into your own psyche to distinguish fear from arrogance.

The course to take is "Offshore Emergency Medicine" taught by Jeffrey Isaac, PA-C, of Medical Officer, Ltd. http://www.medofficer.net Look under Courses. Also look under Articles for thoughtful opinions. The course is designed for home study followed by three days of class practice. The course book, Wilderness And Rescue Medicine by Jeffrey Isaac, is available from Amazon. http://a.co/c3I2Zbn

I took the course years ago. To be relied upon, I would need to take it again. This is what impressed me about the experience:

Think of the human body as a machine. With plenty of clean water, warmth, food, sleep and good social vibes, the body will work well most of the time. But In extremis: No oxygen = no life -- only minutes. 

Think methodically and keep notes about the whole system: Air goes in (not if under water) through nose and mouth to lungs (not if obstructed or muscles not working) into the blood (not if pressure too low –- causes?) bringing oxygen to (1) the brain (which tells heart and lungs to keep working) and (2) the muscles (which pump the blood and move the lungs). Understand the big picture so you can ask the right questions to methodically go through a check list to see what is wrong.

Observe the crew. A talking active person who drinks enough water, eats and defecates, is not shivering, is coherent, and is within their own personality range is probably OK -- at least for awhile. 

Often in class a student would ask how long a human could live with some condition. Answer: “Five.” Next question: “Five what?” Answer: “I don’t know, minutes, days, years” meaning it depends on factors beyond your control and outside your knowledge. Other conditions were separated between deadly if not air lifted, and those not warranting the danger of an air lift.

Keep the obvious in mind, but do not let it blind you from considering unexpected causes or multiple causes. If you do not know how something should look, compare right side with left. While people come in different shapes, they are normally symmetrical.

Remember, you are not the patient: (1) The pain of cleaning a deep wound is not your pain, but do not flinch from doing it properly while still comforting your patient. Your stress will only magnify the patient’s fear and pain. (2) With a conscious coherent patient, you may not do anything without permission. 

“I see you are in pain. I have some training, may I check your body for wounds?” If the patient says “no” explore why, but do not act without permission. 

Perhaps the patient wants to be examined by someone else. Say what you are going to do. Try to get to a “yes” answer. 

“I am going to put your dislocated shoulder back into its happy place, I will not start until you say go, and I will stop if you command me, but together we can do this. Do you need more assurance? Do you want a small glass of whisky? Are you ready to get this done now?”

When you have permission, give yourself permission to let go of your own inhibitions. Focus on your purpose. No one wants a death because you were too embarrassed to do a complete exam. While you lack most medical tools and are neither trained nor licensed as a doctor, you can certainly gently and quickly pat a person from head to toe to disclose hidden injuries.

You must also let go of your own revulsions. Learn to accept the sight of blood. Some wounds are messy, but if blood is not spurting out, blood is not by itself an immediate threat to life. 

Think mechanically. Stop spurting blood with hand pressure. Use washed hands, gloves and sterile gauze pads, if available. Loss of a little blood isn’t the larger concern, it’s the loss of blood pressure. 

Consider whether the patient is a danger to care givers because of Hepatitis C or other viruses transmitted by blood. Have this discussion before leaving the dock. Being at sea requires frank realism.

With a week of home study before the three-day course, you learn that you can do a lot to save lives, offer comfort and a stronger recovery. 

​You can handle many problems with limited resources. Others require years of medical experience and the machines and medications of a hospital. A goal of the Medicine at Sea course is to avoid unnecessary air evacuation at sea. 

Learn the difference between life threatening and scary looking. If possible, make radio contact with a medical doctor but know they may not understand your conditions at sea. 
Know that evacuation personnel thrive on the heroic thrill of doing their job. Your job is to provide dispassionate thought for your patient’s well being. 

In addition to response to trauma, Emergency Medicine at Sea teaches sailors to assess illness, including: infections of eyes, ears, teeth; abdominal pain; chest pain; gastrointestinal problems; respiratory infections.

Air evacuation to hospital may not be possible or fast enough to save a patient’s life. Understand those life and death consequences. 

​Encourage the crew to stay well with healthy eating, hydration, sleep, and proper clothing as well as remaining alert to danger and  physical trauma.
 
Those who will not or can not follow the prescription of the last sentence should not go offshore on a small boat. That would be unfair.

I see in Diane’s 3-4-2017 Blog entry: "Bowlines are great knots. But they do occasionally slip. Make sure you pull the knot tight and leave enough of a tail on the bitter end." 
The word “occasionally” implies a random event. I disagree. Do it right every time, and it won’t be:

1. something to fear or
2. an excuse. 

The bowline can be dangerous given its false reputation for never failing (“king of knots”). See links below for cases of rock climber injury and death. When tying on jib sheets there are four steps to bowline success:

1. Tie bowline correctly
2. Leave extra tail
3. Pull the knot as tight as you can
4. Make sure the knot has “set”

It is only after the knot has been put under great tension of wind on the jib that the knot becomes “set.” Until then,  inspect it often – especially as it alternates between tension and slack because that might cause the knot to come loose. 

In my experience, after many days of high tension use, the jib sheet bowline becomes so tight that it’s impossible to untie it with bare fingers. That is set. 

With a set jib sheet bowline, you are much more assured that it will not untie itself; however, it is still up to you to inspect and determine that it remains OK, and that the amount of tail has remained constant. When it comes time to untie the bowline, you may need to use a marlinspike to loosen the knot and “break its back.”
 
​So be wary of two characteristics of a correctly tied bowline having extra tail: 

• Until it is set, it can come untied on its own when alternating between slack and tension
• After it is set you may not be able to untie it 

Finally, do your own research and gather your own evidence. Be wary of conclusions about knots including this one. 

Discussion of knots is a slippery topic.
​ 
Two References: 
1. Outside Magazine discussion about what happened to a climber when a bowline came undone.
2.  The Great Outdoors site reviews how the bowline performs in different situations.