The Delfe Treasure

15. Of Position and Comfort

Aldrick continued explaining the setting of the islets to Elizabeth. "They use this hill to guide their way into the anchorage, lining it up with what I assume is a singular prominent rock offshore to keep them in safe water." He tapped the drawing. "This shows they are well-learned in navigation. Naval officers before they turned foul."

"What are these figures?"

"They record the position of the anchorage. Its latitude is 22º 17' 15" north of the equator, and its longitude is 75º to 76º west of London."

Elizabeth nodded. "Their latitude is precise to within feet, but why are they so vague with the longitude? A whole degree, near sixty miles."

"Because of the simplicity of determining the one and the difficulty in knowing the other. Latitude can be found by measuring the angle of the sun above the horizon at midday with a quadrant or a backstaff, then using the solar table for the date, quickly calculate the angular distance from the equator. At night, the height of the Pole Star gives latitude."

"And to determine longitude?" 

"This has been a problem since men first sailed away from land. For nearly twenty years now, the King has offered a prize of up to twenty thousand pounds to the first person to devise an accurate method." 

Elizabeth's eyes widened. "Twenty thousand?"

"This shows the seriousness of the problem." Aldrick chuckled. "When I first saw you in Cambridge, I was trying to understand a convoluted treatise on lunar distance as a method of determining time at sea."

"I was intrigued by how serious you were, yet you took time to flirt."

"You were a delightfully welcome relief to the heaviness of Frisius, Huygens, Newton and Halley.

She giggled as she wrapped her arms around him. "I could see you were flustered, and I enjoyed the game of leading you on, seeing if I could get past your timidity."

"You almost did, but I had an engagement with Halley I could not miss, and I needed to be fully conversant with the concept of calculating the time from the moon and stars."

"Time again, why time?"

"The earth's rotation and its relationship with the sun, moon, planets and stars are all precise and calculable. With accurate tables of the heavenly bodies, we can determine where we are in the vast system, but without time, we have no measure of where the earth is in its rotation on its axis. As it turns, the heavens above race past us at fifteen degrees each hour, giving no time reference other than night and day."

Elizabeth bobbed her head as she thought. "Yes, a full three hundred and sixty degrees each twenty-four hours. Fifteen degrees is nine hundred miles." She paused as realisation grew. "We spin at nine hundred miles per hour."

"Yes, in relation to the celestial sphere, thus precise time is essential to fixing our position on the seas. We cannot use a surveyor's chain."

She tilted her head. "Ships have sailed far from land for centuries and crossed all the seas. How have they determined their positions?"

"Poorly." He chuckled. "Since antiquity, we have relied on measuring speed and plotting it with the course steered to calculate our position. This has come to be called deduced or dead reckoning, and this position is only as accurate as the estimate of speed and course made good and the diligence in turning the sandglasses. The longer the voyage, the greater the cumulative error. Extreme caution and a sharp lookout become the orders of the day."

"So, how do we safely cross the seas if we know not where we are?"

Aldrick shrugged. "We sail to the known latitude, then follow it to..."

He paused when the footman knocked and announced. "Sir, your horses are saddled and waiting in the courtyard."

"Thank you, James."

A while later, Elizabeth and Aldrick guided their horses through the busy streets of Westminster to Charring Cross and along The Strand into the City on their way to London Bridge. After they had crossed the Thames, Elizabeth held a fresh rosewater cloth to her nose in an attempt to mask the stench along The Borough.

Finally, they turned into the Kent Road, and within a hundred yards, they were beyond the last houses and into fresher air. After a pause to pay the toll at the Dun Cow turnpike, they continued at a canter along the road through the open countryside all the way to the New Cross gate.

As their horses walked them through Deptford, Elizabeth said, "We were not in London long enough to become re-accustomed to the foul air. How much longer must we endure it?"

"Another eight or ten weeks. Launch should be midweek; then there is the mast stepping, rigging and fitting-out. Mister Stacey has confirmed in a letter that mid-August is still an accurate timing for our sailing away."

They rode into the yard to see Elizabeth fully planked, with her hull painted and her bottom tarred, then Aldrick guided Elizabeth aft.

"Oh, my! So different from her standing in ribs. I love all the windows. And the name."

As they dismounted, Mister Stacey strode across the yard to greet them. "I see from her expression that she is well pleased."

"As am I. This is far more grand than I had envisioned."

"His Majesty's Shipyard has idled many hands, and I have selected the best of them, Sir." He called for a ladder. "The hull is not yet dry, but we can repaint any marks."

Aldrick nodded. "She appears near ready for launch."

"Awaiting only a tide. With the moon now waxing toward full, there should be higher highs the next few days."

Once the ladder was in place, Mister Stacey led the way up, followed by Elizabeth, with Aldrick a few steps behind, ready to assist if needed. He shuddered as he watched her cheeks move in her tight breeches beneath her coattails close above his face.

Safely aboard, Stacey led them aft into the void which was to become the great cabin, and he pointed to the chalk marks on the deck. "We made these from the drawings in your letter, Sir."

After a quick look out through the wall of windows, Elizabeth stepped across and wrapped Aldrick in a hug. "Far beyond my dreams."

Aldrick chuckled. "It is as yet an empty shell awaiting the cabinetmakers' magic. This will soon be as refined as the interior of our St James house."

"Where will our bed be?"

"Beneath these four windows." He pointed to the chalked lines on the deck. "The berth will be built here."

She walked into the corner and knelt. "Will we be able to look out at the sea from lying in bed?"

"We will." He knelt beside her. "I have requested its top be at the level of the cills." He took her in his arms and trembled, then he turned to the master shipwright. "Thank you, Mister Stacey. We will see you in your office in a while."