The Delfe Treasure

23. After the Storm

Toward the end of the first dog watch, the main and fore course sails had been unfurled and set, and all three jibs were up and filled. The seas, though still high, had calmed sufficiently that Elizabeth's renewed speed made it safe to come across to put her port quarter to them.

After the watch had changed, and Wilson had reported being relieved by Franklin, Aldrick went below to plot their estimated position and a new course to steer, explaining his process to Elizabeth. "This is the most northerly of our possible tracks, and this is the most southerly. So we are somewhere in this wedge."

She nodded, then pointed to the dashed line. "And this southerly one is both our most dangerous and most advantageous."

"It is. And these two lines are from our assumptions of the least and greatest distance made good." 

"Again the most advantageous is the most dangerous."

"Exactly! From where would you plot our onward course?"

"From where the two most dangerous lines cross."

"Great." He pointed to the line of islands and reefs north of Hispaniola. "We will use these to establish our longitude. How would you suggest we approach them?"

"I would sail to seven miles north of their latitude and follow that line west."

"Why seven miles?"

"The distance to our horizon from the quarterdeck."

"The distance is ten miles from aloft."

"But you need to sight them from on deck for the fixes. You cannot take the pelorus up the mast."

Aldrick smiled at her, then he took the brass protractor from a drawer and laid it on the chart. "We place the hole over the position, then rotate the axis to the magnetical variation, and —"  

Elizabeth looked up from the protractor. "Is this for the same reason you adjust the course steered to a different one on the chart?"

"It is. The place which attracts the magnet of the compass is not at the north end of the earth's axis, but hundreds of miles away from it. As we cross the ocean, the angle between the magnetical and geographical poles changes, so we shoot the azimuth of sunrise and sunset to find the variation. But the sun also changes its declination every day, so we must adjust our sight using the solar tables. Calculations from our last sunset showed the compass was half a point high, so we will use that." 

"This all becomes increasingly complicated."

"That is its intrigue." He pointed to the chart. "Tell me the route to steer."

Elizabeth centred the protractor on the most westerly of the crossed lines and rotated it half a point. Then placing a rule between the centre and north most part of the Caicos Islands, she said, "Steer west by south."

Aldrick removed the cover from the voice tube and blew the whistle. A few moments later, a voice sounded, "Officer of the Watch, Sir."

"Steer west by south."

"Aye, Sir. Steer west by south."

Elizabeth beamed a smile, then it quickly faded. "We are sailing directly toward land with nothing more than a guess where we are."

"This is often the nature of navigation." He shrugged. "But we have eight hundred and fifty miles, maybe as much as a thousand before we run aground. If we make good twelve knots, we have three days in which to find a horizon for the sun or Polaris so we can calculate our latitude."

Two days later — Thursday, 27th August 1733

A few minutes past one bell of the afternoon watch on Thursday, Aldrick and Franklin stood at the port rail of the quarterdeck swinging the sun across the horizon in the mirrors of their sextants, slowly adjusting the drums. "Now, I think, Sir."

"Aye, I was about to say."

As they walked back toward the hutch, Aldrick continued, "With the declination, we are close to twenty-two forty, still more than forty miles north of Caicos' latitude. I will take these below and do the calculations, then call up with a new course."

"Aye, Sir."

In the great cabin two minutes later, Aldrick read the altitudes from the scales on the  sextants as Elizabeth wrote them in the journal, then he said, "You may do the calculations, but explain each step."

"Are you certain? We have not had a latitude for almost a week. This is important."

"You have watched me often enough. You know the steps. Everything is logical." He chuckled. "Besides, the importance will increase care."

Aldrick watched and listened as Elizabeth corrected for dip and index error, then looked up the declination of the sun for the twenty-seventh of August and applied it to the formula. She checked her calculations again, then said, "Twenty-two, thirty-nine, sixteen."

"Excellent!" He leaned and kissed her. "I love my navigator."

She turned and cuddled into him. "And I love my captain."

They merged in a deep kiss, and trembling when finally they parted, she tugged him toward the night cabin. "Come celebrate our noon sight."

He held his position at the chart table. "As much as I am up for that, first, we need to plot this, then we must calculate a new course to steer." 

Aldrick pulled a larger-scale chart from the drawer, and as he drew the long line on it at their new latitude, he explained, "We will lengthen our estimate of longitude for steering and speed errors, then draw our course from its dangerous end." He laid the protractor on the western end and rotated it for variation, and with a measure on the latitude scale, he said, "About three hundred miles at west, half south."

After Aldrick called the new course up to the quarterdeck, Elizabeth said, "We should raise Caicos Islands late of the forenoon to-morrow."

"Not necessarily Caicos, but reach seven miles above their latitude. We still have an estimated position a hundred miles long." Aldrick pressed his front into Elizabeth's belly. "But this has also grown long. Shall we work on shortening it as well?" He swept her off her feet and carried her toward the night cabin.