LEGO brought out floating boats quite early, and in many ways the first were the best. (I'll explain why later...) This set in particular is interesting as it came out in two versions; one that includes the first minifigs and another that included the non-armless type. (Set 709.)
The police signs are stickers, and are in surprisingly good condition considering the age of the set. (I am missing one sticker on the front though.)
Note the Technic Bush and Axel; they are the old type.
The position of the second figure is not a mistake; I think he's supposed to be sitting down....
The first boats out by LEGO needed a weighted keel to prevent them.... keeling over. (I have tested this!) I suspect this is because of the density of the old hulls and the flat bottom... but I could be wrong. (It can't be just because of the flat bottom as the new cargo ship doesn't need one.)
The keel in detail. The bottom extension is for a motor. (Not included, nor made by LEGO at the time.)
The keel had longer studs. Even now it holds extra firmly.
This is why I prefer the old design. You can extend or shorten the hulls as you please, or even insert other LEGO in the middle.
You can easily add wheels or any other piece to the bottom of these hulls. I wish they would go back to this idea; the 4+ hulls were of this concept but were too wide. (Probably so the keel wasn't needed.)
The old minifigs aside from having odd feet and no arms had a normal stud as the neck. Thus when you turn the head it tends to come off.