Chapter 7 Summary
The father argues against moving from the beach to the tree. He finds the beach easier to protect from intruders. Where they landed, the beach is very rocky, thus making it difficult for ships to make their way in. If he blasts the rocks near the river, an approach by land would also be more challenging.
Elizabeth refuses to give in, saying the heat during the day is oppressive. While he transports supplies from the ship or surveys the island in the shade of the trees, she remains behind on the beach all day.
Finally they reach a compromise. The father will build the house in the tree but they will keep the beach compound as a secret retreat. The children are ecstatic and call the grove of trees on the other side of the river the Promised Land.
To carry all their equipment, they must construct a bridge to cross the fast-moving water safely and without fear of getting the supplies, such as their precious gun powder, wet.
First the father and his sons consider rowing back out to the wrecked ship and confiscating lumber. They even row out, but only a short distance from the shore, they notice a large congregation of seagulls squawking around a pile of rocks inside a separate cove. Curious, they change their direction and pull into shore. There they find the shark Fritz had shot. They shoo the seagulls away and then skin the shark, thinking it may one day come in handy. In the cove, they also find long lengths of good lumber piled on the beach from previous storms. They decide to use the wood for the bridge, saving them another trip to the ship.
The sons help their father find the best spot to bridge the river. Then they tie a rock to a line and throw it over to the other side to measure the width. The father adds a few more feet on either side to stabilize the structure. With a series of ropes and pulleys, they begin construction of the bridge.