as in any jet boat, sand is its enemy. It wears the impellar housing to a point where water passes around the outside of the impellar. Jets can be refurbished or replaced and depending on how well you like your jet you may want to consider changing to stainless steel. Get ready for a sticker shock though.
In water fast, on land their slow.
the smaller they are the less resistance to water and the faster they move.
Particles
No fur so less friction with the water.
The size, shape, and fins make the fish go fast. Some are build for speed and have special 'fins' on the top.
Fairly slowly
in my science book it says pebbles move .75 cm/sec
it depends if its in a hot or cold temperature. hot = FAST cold = SLOW
Well actually, turtles move slow not fast.. unless you are not worrying about it then it will seem like it's moving fast... but in further notice they move faster in water.
They move their tails up and down so fast that it makes swim fast.
It is huge and conjoined together so it lets it move fast in water
Penguins can move quickly in the water, using their flipper-like wings to "fly" through the water at speeds up to 15-25 miles per hour. On land, however, penguins waddle at a slower pace due to their anatomical structure, which is not designed for speed on land.