How can I protect the prop and prop shaft?

[Jon Boat Jim]

I'm new to Nissan/Tohatsu motors.
I had a 7.5 HP Evinrude that used brass shear pins. On several occasions, I have sheared a pin during a small creek or low water river trip. The NS18E2 that I just bought, has a stainless steel prop. I took it off and discovered that it does not use a shear pin. What can I do to protect the prop and prop shaft?

 

[Sea Rider]

Re: How can I protect the prop and prop shaft?

You could install one of those round devices that protects props, if stainless steel much better. Used to install Prop Guard on Tohatsu 30 HP, although well made and designed, the only issue, are plastic, breaks very easily when hitting sand beds at some speed..

Happy Boating

 

[TOHATSU GURU]

Re: How can I protect the prop and prop shaft?

Your propeller has a hub that is designed to break in order to protect the propshaft and to some degree, the propeller blades. IE Shear pins are not used on modern engines as they break at the worse possible time...So, do nothing with your prop and you will be much better off.

Also, there is no reason for you to be using a SS prop unless you are on a very light hull in a deep water situation.

 

[Jon Boat Jim]

Re: How can I protect the prop and prop shaft?

Tohatsu Guru,
I have several questions:
1) The hub that you refer to....Is that the propeller hub or the "thrust holder, propeller" (362-64231-0) that I found in the parts catalog? Should I have a spare "thrust holder, propeller" on board?
2) I don't understand your comments about the SS prop. I have the engine on a 15ft aluminum jon boat that would be probably considered as medium heavy for this type of boat. Would you explain your comment a bit further?

Jon Boat Jim

 

[Sea Rider]

Re: How can I protect the prop and prop shaft?

Correct, hub is the propeller hub located inside prop center. No need to hava extra thrust holder on board, rear side of prop centers and rests there. But could have a second prop just in case...

Happy Boating

 

[TOHATSU GURU]

Re: How can I protect the prop and prop shaft?

1) Hub and a spare would not be necessary.

2) You have to start off with a basic understanding of what a SS prop is for. Aluminum propellers are normally what people should be running in shallow water where there is risk of hitting a submerged object or just as an economical propeller. SS props should be used in applications where there is little or no risk of damage, where the micro increase in speed/holeshot is necessary because the boat is underpowered and you are trying to get the most possible out of it or because "I like to go fast".

Basically SS props are for micro increases in performance. Unfortunately many people use them with the mistaken idea that, because SS is harder than aluminum, they are better because you will not tear your prop up as quickly. This is what is known as a:

BAD IDEA

Yes, the prop will take a slightly harder hit without tearing apart, but that comes at the expense of a greater risk of catastrophic damage to the lower unit. While SS props have slipping hubs like aluminum props, you still have to take into account the greater mass of SS over aluminum. It's just a risk that people should avoid unless they have money to burn or think they will be lucky.