Spar torpedo craft and extreme crew risk

Were spar-torpedo boats and early submarines precursors to Second World War suicide craft?

Yes; their close-contact attack method exposed crews to similarly extreme danger.

A spar torpedo required a small craft to bring an explosive charge into direct contact with an enemy hull. The answer readily accepts the comparison to later suicide craft because the operator had to approach at extraordinarily close range. The danger applied to both surface boats and the primitive submarines that carried the weapon. The emphatic refusal to go near one conveys how little margin for survival the attack profile offered.