Prop crack

verytricky · 20-06-2006, 09:17 AM

Any recommendations on repairing a crack on my prop? The smaller of the two out of the duoprop set has a large crack, and this is causing quite a problem..

Personal experiance recommendations please, not just a list of everyone who can fix things..

CB1 · 20-06-2006, 12:24 PM

Get a new set. Dont bother repairing it will go somewhere else.

Matt · 20-06-2006, 01:02 PM

If it's near the root, I tend to agree with Chris.

DAVE · 20-06-2006, 04:42 PM

Absolutely...

verytricky · 20-06-2006, 07:23 PM

No body has been able to replicate the prop.

It cavitates on two of the blades, not the third, yet is 1 mile faster than the closest matching prop

Matt · 20-06-2006, 07:34 PM

It "might" be possible to weld if heated up good and hot before hand. I suspect a normal prop repair place would be tig welding it, which induces loads of stress into the material, hence not so good for you. But "if" the prop is hot enough when welding, the overall induced stresses should be low enough. Heat treating after welding would also help.

But, in conversation with Jon the other day, we reckon the rear prop does feck all anyway, which the fact your fastest prop is the one that cavitates (ie the rear prop unloads) supports. Reckon you should cut the blades off the rear prop, just run the hub, and see what happens.

You could also reshape the leading edge of the rear prop to force it to cavitate, or just cut the blade diameter right down.

Matt · 20-06-2006, 07:36 PM

Should add, it's been 10 years since I did metallurgy, so I reserve the right to be talking shite!

Foolish · 20-06-2006, 10:20 PM

Quote:

Originally posted by Matt

But, in conversation with Jon the other day, we reckon the rear prop does feck all anyway, which the fact your fastest prop is the one that cavitates (ie the rear prop unloads) supports. Reckon you should cut the blades off the rear prop, just run the hub, and see what happens.

so do you reckon it would be better to a "SP" lower rather than the "DP" ??

Matt · 20-06-2006, 10:45 PM

Yeh, more top speed, but probably at the compromise of handling and acceleration.

verytricky · 20-06-2006, 11:27 PM

Quote:

Originally posted by Matt
But, in conversation with Jon the other day, we reckon the rear prop does feck all anyway, which the fact your fastest prop is the one that cavitates (ie the rear prop unloads) supports. Reckon you should cut the blades off the rear prop, just run the hub, and see what happens.

OK,

The front prop is 100%
I have a spare rear prop, which is thinned and balanced - it is also as close to the same spec as the existing race prop.
*BUT*
When I tested combinations of props, the race front prop with the spare rear prop was almost a mile slower than the full race setup. I already tested that whilst trying to get the most speed out of the boat. Why??

FWIF, I do have a very very very trimmed rear prop - it was a broken one I picked up for next to nothing, and 'worked' it down to 9 inches, thinned and cut away as well. Handling goes for a ball of shite, but it does add about 1/2 a mile onto the top speed - so I feel sure I will get the British Speed record for V24 this season.

All the work and experimentation for Conniston last year is definately paying off in the V24 Championships this year......

jw. · 12-07-2006, 12:25 AM

Quote:

Originally posted by Matt
...But, in conversation with Jon the other day, we reckon the rear prop does feck all anyway, which the fact your fastest prop is the one that cavitates (ie the rear prop unloads) supports. Reckon you should cut the blades off the rear prop, just run the hub, and see what happens.

Matt, would you like to share your conversation?