[hpv-boats] converting pedal power to prop power right angles

[mark McWilliams]

How do you change the angle of drive the 90 degrees needed to change the pedal power which is 90 degrees to the direction of the propeller ? 

pedals 
pedals >>>O < possible bike gears
                  v
                  v
                  v
                  v
                  v>>> propeller

If I wanted two 90 degree turns one going into the water and the second to the propeller then how would this be achieved in an application that will certainly get very wet and stay wet. 
Are there bevel gears that can be purchased ?
Have any of you made your own bevel or helical gears? 
If any of you have made bevel or helical gears how did you do it and how well has it worked?