Halkett was an amateur inventor , and during his spare time whilst serving in the navy he worked on solving the problem of how to design a boat that would be small and light enough to transport easily on foot through wilderness , but robust enough to carry people in safety across wide bodies of water .
During his spare time while in the navy , he worked on building a boat that would be small and light enough to be carried through wilderness , but strong enough to carry people in safety across wide bodies of water .