This is one of the most common questions of ship stability that what is the difference between a Stiff ship and a Tender ship.
Let us have a look at them one by one.
DESCRIPTION OF A STIFF SHIP
- A stiff ship (vessel) is one with unduly large GM.
- In such vessels angle of roll and period of roll is very small.
- Rolling is violent and irregular.
- It is uncomfortable for the crew on board because of jerky movements.
- Hull of the ship undergoes severe stresses.
- General cargo is likely to break loose due to jerky movements.
- Bulk cargo is less likely to shift as angle of roll is small
- There is no likelihood of vessel becoming unstable during passage owing to consumption of Fresh water, Fuel and due to Free surface effect.
- Vessels in a stiff condition have a greater ability to withstand the loss of GM (due to bilging).
- Stiff vessels have a greater ability to withstand transverse shift of cargo.
- Generally tankers and bulk carriers are in stiff condition.
DESCRIPTION OF A TENDER SHIP
- A Tender vessel is one with a small GM for her size, nature, type.
- In such vessels angle of roll and period of roll is large
- Rolling is smooth and regular.
- It is less uncomfortable for the crew on board as compared to Stiff vessels.
- Less severe stresses are set up on hull of the ship.
- General cargo, if properly secured is less likely to break.
- Bulk cargo is more likely to shift as angle of roll is large.
- There is high likelihood of vessel becoming unstable during the passage owing to the consumption of fuel, fresh water and due to Free surface effect.
- Tender vessels have less ability to withstand a loss of GM because already the GM of such ships is small.
- A vessel in tender condition has less ability to withstand transverse shift of the cargo as the list caused due to shifting of cargo is large.
- Generally Timber ships, Ro-Ro, Car carriers and container ships are in Tender condition.
Hope this covers all basic aspects of stiff ship tender ship.