The Secret of Skeleton Island

As a kid I mostly read the Rick Brant series books.
I have often heard fans of those book refer to the Ken Holt books.
I have now read a couple of those and I understand the attraction.
I liked the book, the mystery elements are similar to the Rick Brant books but without the science and engineering.
I thought the big action sequence (involving several boats and a hotel) went on a bit long
but it was a well thought out plot.