A tender ship is one with a very small GM caused by KG being too large. This occurs if too much weight is placed high up within the ship. The ship will have insufficient stability, righting moments will be very small when heeled causing the ship to be sluggish and slow to return to the upright. Roll period will be long. (A tender ship is still a stable ship i.e. M is above G.)
In other words we can explain stiff vessel as:
- Small GM (but not negative ) due to loading on top
- Ship rolls very slowly
- Uncomfortable but better than stiff ship
A very small GM should be avoided for the following reasons:
- Because of the small righting moments the ship will only offer limited resistance to being rolled, causing the ship to be rolled to larger angles of heel. This will increase the risk of water being shipped on deck.
- The ship will be slow to return to the upright and will tend to remain at the extent of the roll for a comparatively long time. This will create greater and more prolonged strain on cargo lashings and increase the risk of cargo shift.
- Rolling to excessive angles of heel is also uncomfortable for the crew and injury may result.
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