Kiwi Prop - Word of Caution

[theotter]

I hope I am not teaching the proverbial to suck eggs but those with Kiwi props will know that the main retaining nut is prevented from backing out completely by two grub screws. The grub screws protrude into a recess in the main nut thus preventing the main nut coming out of the hub of the prop. However, as I found out by chance, one only has to back off the grub screws a quarter turn, breaking the friction but still within the recess, for the main nut to be backed off completely, bringing the prop with it so to speak. I have explained this to Vecta Marine (Alan Pollard) who agrees this is possible. Although the chances of this happening on its own are small, it does undermine the perceived (well mine at least) effectiveness of the grubscrews.

I have a Volvo sail drive so a belt and braces solution, and one I will be doing, is to make up a 1/2 inch square socket drive sized washer complete with a M8 machine bolt of suitable length and loctite and secure it in the end of the prop using the female thread in the drive shaft. This was also suggested by Vecta Marine.

Good sailing.

 

[nimbusgb]

Interested in making up 2?

I'd use one, I'd hate to loose my prop but I did use the right locktite on the propnut and the grub screws.

 

[wizard]

i have had a Kiwi for 5/6 years now and use a fresh bottle of Loctite 243 each year for the two grubscrews and not had any problems at all. The boat is in the water all year and used all year. Generally the only problem is - will the grubscrew break the seal before the tiny allen key bends!