Your vessel has a midships engine room and the cargo is concentrated in the end holds. The vessel is __________.
A. sagging with tensile stress on main deck
B. sagging with compressive stress on main deck
C. hogging with tensile stress on main deck
D. hogging with compressive stress on main deck
A. sagging with tensile stress on main deck
B. sagging with compressive stress on main deck
C. hogging with tensile stress on main deck
D. hogging with compressive stress on main deck
The best answer is hogging, Choice C.
ReplyDeleteMidships Engine Rooms are lighter than full cargo holds, so the ends of the vessel are acting downward due to gravity with more weight than buoyancy per unit length. At the middle there is more buoyant force acting upward than weight acting downward per unit length. This will cause a Hogging situation.
The second part of the question is the deck in stress (being pulled apart, under tension) or in compression (being squeezed together or being comperssed). In this situation of hogging you can think of the deck being stretched and the bottom plating being crushed, similar to bending a stick with both hands pulling down at the ends and pushing the middle of the stick up with your thumbs. So the deck is in Tension or having Tensile stress.
DO YOU AGREE OR DISAGREE?
AGREE. LETER C IS CORRECT
ReplyDeleteGiven the fact that the vessel has a midships engine room and the cargo is at the ends:
Cargo is way heavier than the engine room.
Cargo at the ends mean the ship is hogging because of the momentum.
So, the upper strakes are certainly being pulled apart and the strakes close to the keel (let's say the garboard strake) are being squeezed together.
Thank you very much, Cap. William.
Here's an explanation of why ships hog and sag, it is amazingly written just as Capitan William's answer.
ReplyDeletehttps://www.quora.com/Why-do-ships-bend-hog-and-twist-at-sea
Thank you very much
Charley
ReplyDelete