'Really?' Halt said.

Gundar glared at him. 'Well, of course. That's why so many of them start heaving their guts up the minute they step aboard.'

Will saw the conversation heading back into danger. 'So tell us about this design. How does it work?'

'The most important part of it is that it lets us sail into the wind,' Gundar told them.

'Into the wind?' Halt said. 'How can that be possible?'

Gundar puckered his face in a frown. He was reluctant to admit any shortcoming in his ship, but he knew that if he didn't answer truthfully, his audience would see through his boasting eventually.

'Not really into the wind,' he admitted. 'We can sail across it, gradually making ground against it. We're able to move at an angle to the wind so we can still make progress when it's on our bow. No square-rigged ship can do that.'

'So that's why you were constantly changing direction yesterday when the wind was against us?' Selethen asked.

'That's right. We move diagonally to the wind. Then after a while, we switch and go the other way, gradually zigzagging in the direction we want. We call it tacking.'

'Why?' Alyss asked and he frowned again. He'd never queried why the manoeuvre he'd described was called tacking. Gundar was an accepting person, with a non-inquiring mind.

'Because…that's what it's called,' he said. 'Tacking.'

Wisely, Alyss pursued the matter no further. Will hid a small smile with his hand. He knew Alyss and knew that Gundar's answer was totally inadequate to her inquisitive mind. He thought it best they should move on.

'So how does it actually work?' he asked. Gundar looked at him gratefully. This part he could explain.

'Well, the young Skandian lad who designed it,' he glared quickly at Halt, daring him to challenge the inventor's nationality again, 'had spent a lot of time studying seabirds, particularly the shape of their wings. He thought it might be a good idea to stiffen the front edge of the sail like a bird's wing, and shape the sail itself so it was triangular, not square.