Boatnerd Discussion Forum

Guest wrote:Timerover, nice to see you again. Have you found a ship for your expeditions yet?

I have been having more health problems, so for the present, I am not working on any explorations, although I would like too.

Timerover, nice to see you again. Have you found a ship for your expeditions yet?

The key factor in hull strength is the depth of the hull girder, defined as the distance between the ship keel to the highest continuous deck of the ship. The greater that distance, the stronger the hull, assuming that it is built to current standards. The length to beam ration is more important when it comes to powering a ship, as a longer ship takes proportionally less power to propel. For a long time, the Panama Canal locks set the limit on the size of U.S. Navy ships, as they were required to pass through the locks. That was discontinued with the design of the Montana-class battleships during World War 2, and with the very large fleet aircraft carriers built after the war.

When it comes to the very long ships, the problem is that the hogging and sagging stresses on the ship are increased by the greater length compared to the average wave spacing. As those stresses tend to be concentrated in the midships area of the hull, excessive stress can lead to the ship breaking in two under severe weather conditions and exception wave sizes.

I've seen papers written on the hull to depth ratio for Great Lakes ships, but never for the length to width ratio.

The classification societies set standards for both, but there is more concern with the length to depth ratio, as the greater it is, the more hull springing there can be, though springing can be reduced by changing a vessel's heading.

There were several studies done on hull springing in the late-1960s to the 70s.

Guest wrote:The Cliffs Victory would have had a length to beam ratio of 11.5
Beechglen 11.3

These, along with the LAT, AAA's and Kaye E Barker all have very high length to beam ratios. Does this effect how they handle in a heavy sea ? More flexing perhaps ?

The Cliffs Victory would have had a length to beam ratio of 11.5
Beechglen 11.3

I'll throw in the Cliffs Victory which was 716 x 62

In its final stage of 680x60 I believe the Beechglen takes the cake on that one.

William Lafferty wrote:If we go by a standard measurement, namely registered length, the Tregurtha is 812.5/75.2 = 10.8. However, most canallers back in the day were around 6. Consider the Mondoc, the former William Schupp (from the 1948 Canadian List of Shipping): 253.5/43.3 = 5.85, or almost half the ratio of the Tregurtha. Then again, the Victory of 1895 (Merchant Vessels of the United States, 1895), a big boat for the day, was 387.5/48.3 = 8.02. So what I'm trying to say is, there were many, many more "slender" boats before the Tregurtha, those ratios determined by the canals in which they would operate.

Thanks for the info but that isn't what I meant. Let me rephrase my question. Has there ever been a GL boat with a longer length to beam ratio ?

a 10 to 1 ratio is more slender than 6 to 1

How does a lower ratio than 11:1 make them more slender?

If we go by a standard measurement, namely registered length, the Tregurtha is 812.5/75.2 = 10.8. However, most canallers back in the day were around 6. Consider the Mondoc, the former William Schupp (from the 1948 Canadian List of Shipping): 253.5/43.3 = 5.85, or almost half the ratio of the Tregurtha. Then again, the Victory of 1895 (Merchant Vessels of the United States, 1895), a big boat for the day, was 387.5/48.3 = 8.02. So what I'm trying to say is, there were many, many more "slender" boats before the Tregurtha, those ratios determined by the canals in which they would operate.

Is the Lee A Tregurtha the most slender boat to ever sail the Great Lakes ? At 826' long and 75' wide she has a length to beam ratio of slightly over 11:1.