Safety (Guard vs. Propeller)

Question · 04 June 2010, 18:44

Hi,

I was reading the forum and some other sites about the pros and cons of apparatus so called propeller guards (what I'm looking for is a guard against the propeller actually

), then I came across with this:

http://www.abc.net.au/tv/newinventors/txt/s2736928.htm

What do you think?

Q

PS: I couldn't find one, but if there's already a thread about this please redirect me : )

donegaldan · 04 June 2010, 22:21

Nice find.

Wonder what the performance is like v's ali and stainless.
Be interesting to see if it ever makes it to market.
handy for safety boats, and might even save a gear box or two.
be interested to see has anyone seen of them before.

God I'm full of questions on a friday night....
DonegalDan

SeaSkills · 05 June 2010, 05:54

There was some talk of this when I was in Western Australia before Christmas. It certainly sounds interesting. There is some more information and discussion here; http://rbbi.com/pgic/ptech/safetypro...ypropeller.htm

I won't be rushing out to get one until it's been tried and tested, but I do think this worth watching

Ian

Simon B · 05 June 2010, 13:00

Looked like a large leading edge so pressure is reduced. This would lead to less slicing of the water also. My initial guess would be a big drop in efficiency/performance. It'll spin as fast yes but not deliver.

The key is training and awareness, divers operate near props but accidents are rare. If you are really concerned a jet is the best option however expect a 25-30% in hp and a corresponding hike in fuel use.

My lottery fantasy boat has jets of course!

Question · 05 June 2010, 16:42

Quote:

Originally Posted by Simon B

... jet is the best option however expect a 25-30% in hp and a corresponding hike in fuel use...

A jet would only be a long term project for us either, thus it seems I'll stick with conventional prop guards for now.

Thanks for the replies.

Best

Q

sarahscottiedog · 05 June 2010, 22:00

Hooray

what a great idea! would love to see and trial one just to see what the performance is like, and find out how much they cost. Any one find a price for one anywhere ? or if they are available in the UK?

Simon B · 06 June 2010, 16:06

A long time ago we tried one of these;

Propguard

It got destroyed before I could get a realistic experience of of good or bad it was.

sarahscottiedog · 06 June 2010, 16:56

SO how did it "get destroyed" ? Operator error ? or failure ?

Simon B · 06 June 2010, 17:28

Operator error most definitely, they got to close to rocks and were pushed against them by the waves. We did not re-fit another one and it is still my worst nightmare as a dive boat handler. All commercial dive ribs I've seen do not have prop guards either.

boristhebold · 09 June 2010, 09:58

Quote:

Originally Posted by Question

Hi,

I was reading the forum and some other sites about the pros and cons of apparatus so called propeller guards (what I'm looking for is a guard against the propeller actually

), then I came across with this:

http://www.abc.net.au/tv/newinventors/txt/s2736928.htm

What do you think?

Q

PS: I couldn't find one, but if there's already a thread about this please redirect me : )

I cant see how it would work, I dont fancy sticking my arm in tio find out

Daibheid · 09 June 2010, 10:11

Quote:

Originally Posted by Question

http://www.abc.net.au/tv/newinventors/txt/s2736928.htm

What do you think?

I thinnk it's a great idea but it's rare to see a prop without some marks on it's edges no matter how careful we are with them. I'd expect teh prop must be made out of glass-filled polycarbonate or a similar engineering type plastic to be anything like rigid enough to transmit power. If that's the case as soon as it picks up a few nicks and scratches it'd saw an arm almost as fast as an alloy prop.
On the plus side - the fat leading edge would definitely cost some efficiency but going by the speed impact of the propguard on my Zapcat, this new prop would probably be way more efficient than a guarded prop.
Of course that's without the slots in the blades which make no sense. You don't see aircraft wings with slots out of their main lift surfaces.

willfinch36 · 09 June 2010, 10:57

If you use your head I cant really think of a reason why you would need a prop guard....

Shame we live in the real world and not the ideal world... (everyone using their heads!!)