Trojan Boat Forum

When I purchased my boat I found an extra set of props in the bilge and thought this was due to the previous owner changing the pitch. But upon further investigation they are the same 16x15 with cup (dont know how to tell if it is light or super cup, but its cupped).

The only difference is the ones off the boat are bronze and the ones on the boat have AL stamped on them and when I scratched the hub slightly it was silver under like aluminum. Would they be aluminum or a light bronze alloy? And why, whats the difference?

Might they be NiBrAl and all you can see is the Al? Ni(nickel)Br(bronze)Al(aluminum)

I will look, if so why the change?

As oposed to a brass propeller, NiBrAl is an alloy that will deflect alot less under load and which transfers the power from your engine to the water much more efficiently. The difference is most noticable when getting up on plane. (holeshot)

What a great find! Spare props are a bonus. The props on the boat are an upgrade, if they are Nibral, & It sounds like they are.

You might want to take the spare set to the prop shop and have them scanned. That way you will know their condition in case you need to use them. You wouldn’t want to change a dinged prop with another bad on.

Keep looking, maybe you'll find a shaft or two.

Just wanted to open this post again with another question.

It seems that both sets are NiBrAl 16x15 cupped, dont know why, maybe it was a 2 for 1 deal or something. But my question now is they have a black patina or maybe a dark dark grey. Is this normal? or should I focus on polishing it up? If so with what?

I also noticed my rudders are dull and dark grey to match, but with a little rougher finish, should these be polished to.....

Last question, its a fresh water boat could this be caused by electrolysis?