Hi
I have recent purchased a 2nd hand quicksilver s/s 14p prop for my yamaha 50hp fitted to a zapcat, when comparing it to the quicksilver s/s 16p prop that was fitted when i bought the boat I have noticed that one the blades on the 16p are thinner(thats fine)but also the hub of the prop that goes into the gearbox housing has been turned down and is black in colour. I am assuming the black colouring is from exhaust gases not going through the prop but around the outside.
So finally to my questions:
Is this a normal modification? if so why? if not, this will cause cavitation wont it?
Any help and advise will be great.
Thanks

Hi,

First of all, do you want to race?

The mod to the 16" is standard, yes. The lighter the prop, the quicker it will rev. But you need to find the balance between a very light prop that easily pick up damage and a thick and heavy one. At the end of the day is your 1. Prop choice for certain conditions 2. Very important, your setup of the boat.

Regarding cavatation: 99% of the time you cavatate, your boat setup is wrong, or you are to hard on the throttle. Remember to be smooth and lower your setup millimeter by millimeter.

Other advice if you want to race: Get yourself a Tohatsu. Lots more bottom - and top end. Ceaser Ratcat, beautiful all-round boat. If you would like more info, feel free to contact me. I love the sport.

Kind Regards

Steyn Basson
Pilot: Team Champs 23 Blueprint class in RSA<br /><br />Post edited by: Revman, at: 2007/03/31 19:32

Thanks for the info.
No I don't want to race I have the boat just for fun.
It does suffer with cavitation a bit but my son who crews for me is only 13 and weight 50kg soaking wet and I feel that is some of the problem because when he drives and I crew it does not cavitate, this would change the engine height and trim though so perhaps i try the engine a bit higher, at the moment the cavitaion plate on the engine is about 1.5 cm below the transom plate.
any advise would be great as I am new to this type of boat.
Julian

Julian, the prop should not let the exhaust gasses go arround, the hub is there to prevent that from happening so it must be the wrong prop you got with the boat, and yes it will cause cavitation, as that is exactly what cavitation is .... air by the prop blades .......



Hey Steyn Basson, I want some info, what is your e-mail adress, there is no PM function on this forum .......

Sorted the cavitation out it appears the hub had ben turned down, possibly to fit a different engine, I have done a temporary repair with some filler to make the hub a snug fit in the gearbox housing and all cavitaion has gone ,so it seems that was the problem all along.

glad to hear it is all sorted now, funny how a small thing like that can cause so much frustration ......