Bookmark and Share Email this page Email Print this page Print

March/April 2014 Issue 216: Coal fire aboard British Isles

Feb 27, 2014
Pamir a Cape Horn square-rigger similar to British Isles.

Pamir a Cape Horn square-rigger similar to British Isles.

The winter of 1905 was a particularly harsh one for square-rigged ships sailing west from Europe ‘round Cape Horn. Claude Woollard, master mariner, writes in his book The Last of the Cape Horners, that “out of one hundred and thirty vessels which sailed from European ports to round Cape Horn, only fifty-two appeared to have reached their destination without mishap. Four were wrecked, twenty-two put into harbor to make good their damage, and forty-nine had not arrived, or were not accounted for, by the end of July 1905.”

These numbers translate to only a 40 percent chance of success, a dismal record for the ships and for the men who sailed aboard them.

During that terrible winter, British Isles, a full-rigged ship built in 1884 in Glasgow, Scotland, with an LOA of 308 feet, left Cardiff, Wales, carrying a cargo of coal. British Isles, bound for a Chilean port, was approaching the Cape. Unfortunately, if coal is stowed incorrectly or gets wet, fire can break out from spontaneous combustion.

On this passage Capt. Barker discovered from regular temperature readings that the hold was heating up. Before departing, Barker had been informed by the ship’s owners to “keep the seas,” he wasn’t to stop at any harbors. Barker, heeding those orders, decided to solve the coal fire problem while at sea. On July 24 all hands were called on deck as smoke rose from the main hatch.

The captain had two choices: close off the ventilation in the hope of smothering the fire or open the hatches and get to the hot spot deep inside the hold.

The risk in opening up the hatch was that it would provide fresh air to the fire and make it worse. Nonetheless, Barker chose to actively fight the fire. He ordered eight crewmen into the hold with shovels. Another six ran a bucket hoist to deposit the coal onto the deck. The men in the hold were not only hot, they were breathing noxious coal fumes.

So from daybreak to late at night, eight men shoveled coal, trying to locate the fire. Barker had no desire to waste any of the coal, so he prohibited any from being thrown overboard. Lucky for the skipper and the crew the wind held steady from the northwest so that the sails required little trimming. The temperature in the hold climbed from 170° to 200° F. Recalled one, “the heat scorched the soles of our feet, as we frantically hopped from one foot to the other to obtain a moment’s relief and kept hopping for hours on end...”

On the fourth day, the fire was finally located and the burning coal was tossed overboard. The remaining coal then needed to be re-stowed.

Let’s join British Isles in the South Atlantic approaching Cape Horn on July 24 at a DR of 53° 15’ S by 63° 20’ W. The skipper takes a sight of Venus at twilight (time of the sight is same as the time of Civil Twilight). Height of eye is 30 feet, no sextant error. He’s hoping to get a Venus LOP. The Hs is 15° 40.6’. We will use the 2013 Nautical Almanac.

A. What is the time of Civil Twilight at the DR?
B. What is the Ho?
C. What is the Intercept?
D. What is the EP?




Answers:
A. Civil Twilight is at 21:16:20 GMT
B. Ho is 15° 33.1’
C. Intercept is 6.1 nm toward
D. EP is 52° 57’ S by 63° 44’ W
 

Edit Module

Old to new | New to old
Mar 2, 2014 04:15 pm
 Posted by  Jack

I don't get these answers.
I think civil twilight is 21-13-20GMT. I believe LAT adjustment was overlooked.

Likewise, I get Ho. 15-32.0' and intercept of 19.8 away.

Anyone else see this?
Jack

Mar 6, 2014 02:09 pm
 Posted by  ckreitlein

I did not these answers either, ...neither civil twilight, and certainly not Ho as listed above. Both are way off. Ho is 15-32. Civil Twilight is 21:12:45. as in ... for DR lat almanac list is 54 degree at 16:57. With interval of 3 min btwn degrees, add .75 min (DR lat of 53-15 = 1 degree 15 min = add of .75 of interval or 2:25 to lower time)or 2:25 min added to 16:57 for local CT of 16:59:25, then add Dlo of 4:13:20 (L of 63-20 = Dlo 4:13:20) for CT exact of 21:12:45 UT. Am I lost or....?

Mar 6, 2014 02:52 pm
 Posted by  Ocean Navigator

Thanks, Jack & CKReitlein for your comments.

We probably made a mistake here in the way the problem was constructed. Assigning the sight time to be the time of civil twilight is too imprecise. The time of twilight need never be calculated to the exact minute since you should be on deck anyway getting ready for your sights. Most folks don't calculate the time and then rush on deck at that precise minute. And the arrival of twilight is a gradual process not a sudden event. Ultimately what defines the navigational utility of twilight is the ability to see stars and the horizon at the same time. So, twilight really starts when the first star (or planet) is visible and you can begin making sextant observations. From now one we'll give you a precise sight time to prevent the confusion we saw here.

Not sure where you guys got your Ho number. Here's our breakdown.

Hs 15° 40.6'
dip -5.3'
Ha 15° 35.3'
alt. -2.3'
addnl +0.1'
Ho 15° 33.1'

Mar 6, 2014 03:50 pm
 Posted by  ckreitlein

Yes, roger all you said on catching twilight. I only commented because I thought I knew what I was doing, then tried to get the magazine answer and failed... destroyed my confidence! lol

Hs 15-40.6 yep
dip -5.3 yep
Ha 15-35.3 yep
alt. -2.3' ???...for 15-35.3 I see -3.4
Am I wrong?

sorry to "nit pic" this, but just want to confirm I do or do not what I am doing.

Mar 6, 2014 04:26 pm
 Posted by  Ocean Navigator

You are right about the altitude correction. Should be -3.4. We used a different version of the Hs when constructing the problem. We changed the Hs but then failed to change the altitude correction for the new Ha.

Good catch.

Add your comment: