12:16.174S 174:48.285W

Working our way South towards Tongatapu we took one more overnight stop on the way down, anchoring between the islands of Nomuka and Nomuki Iki. It was a lovely day sail down, with whales keeping us company, tail slapping behind our boat. As we navigated our way down we came across a feature on the charts that we'd not encountered before: blind rollers. These, it turns out, aren't some sort of curtaining (blind rollers, not roller blinds!), they are big waves that can't be seen from certain points of view. As you sail alongside the area they are in you start to see bumps on the horizon, looking like little islands, then you realise they are moving, and, like those pictures that you look at for ages before suddenly you can see the horse in them, you realise that they are a sequence of big breakers passing along the horizon, seen end on. Once you are past them, looking back, all is clear; there's a shoal forcing the big Pacific swell to break with wave after wave rolling in. But from the other point of view there's no white horses to be seen, no sign of them at all.

As usual we went ashore to explore a little, climbing on the wreck of the fishing boat that had washed up there and venturing inland with Franz, from Vela. We were looking for fruit - mango or figs, but only found huge rubber trees, 50 ft high, huge examples of the plants everybody's parents had in the living room when I was growing up. When you broke off a leaf the sticky white latex trickled out.

We realised that we were sheltered but hadn't realised quite how effective the reef and islands were until the next morning when, as soon as we cleared the reef we were rocking and rolling, the big ocean swell forming short steep waves as it passed over the shallow plate we were sailing down. The day sail down to Tongatapu had started as it meant to go on: plenty of bounce, plenty of water over the decks and plenty of wind - but right on the nose!