Theory:

     I could not understand why all the elders were so upset. I remembered the several sea adventures I had read about. Excitedly, I turned to the elderly gentleman sitting next to me. “Uncle, won’t it be thrilling to face a storm on board a steamer? Have you ever been on a ship during a storm?”
 
     “It can be quite unpleasant, you know,” he replied rather severely. “I remember a time when the ship on which I was travelling ran off course. We were wandering on the ocean for a couple of days.”
Explanation:
 
Vasantha was confused as to why the elders were so concerned. She didn't know the reason behind people's strange behaviour in worrying about the storm rather than enjoying that. As a child, she didn't want to stress herself. Also, she was more attracted to adventures. Instead, she decided to observe nature's beauty. Apart from her age, her curiosity was also another reason that challenges elders' age and experiences.
 
Vasantha's mind had been preoccupied with the stories of sea experiences she had read about. Vasantha then began to approach a man sitting next to her. "Uncle, won't it be exciting to face a storm aboard a steamer?" she inquired. She also questioned as to if he had ever been on a ship during a storm. She was excited as she awaited the ship's arrival in the Indian Ocean.

The stranger's reply to Vasantha was the complete opposite of what she had expected. He told her that it would be so bad and unpleasant to be on a ship during a storm. He then shared his bad experiences while being on a ship during a crisis. It seemed that their ship wandered for a couple of days on the ocean.
 
Meaning of difficult words:
  
S.No
Words
Meaning
1.
Adventure
An unusual, exciting or dangerous experience
2.
Off course
Something that is lost or confused
3.
Severely
Very badly or seriously
4.
Unpleasant 
Not enjoyable or comfortable
5.
On board
On a ship or an aircraft
6.
SteamerA ship that is driven by steam
7.
Strange Unusual and different in a way that is difficult to understand 
8.
Concerned Worried and feeling concern about something
9.
CuriosityA strong desire to learn or know about something
10.
Wandering Moving away from the proper or normal way without a sense of direction or purpose
11. CrisisA difficult or dangerous situation
Reference:
State Council of Educational Research and Training (2018). Term-3 English Standard-7. Man Overboard - Vasantha Murthi (pp. 125-130). Published by the Tamil Nadu Textbook and Educational Services Corporation.