GWCPWC

Hi, just purchased a used SP in unknown condition, has been sitting a while. There is no battery in it, but I hooked up a booster to the cables and when I pressed the starter button a loud warning siren(whistle) started going off and wouldnt stop unless I unhooked the cables, at the same time it kinda seemed like it was cranking, but didnt sound exactly right????

also there is a short black cable(ground?) in the engine compartment in addition to the negative battery cable that has an eyelet on each end, looks like one end goes to the battery, but does anyone know where the other end goes?

any help would be greatly appreciated, hope to have this thing in the water soon.