i have a 87 comp and well... 25 bucks will get you 250 pounds of sand at the hardware store and i usually throw them ontop of the gas tank.. with a full tank and stratiegically placed bodys we get a nice wake... the sand is easy to move around and we will throw them up under the bow but ya gotta be careful not to submarine! we recently bought a 540 pound fat sac... but we cant get the pump to work. but we are gonna try that soon we might sink her though...