Prop guard

Neal · 31 May 2005, 13:25

I have been looking back at some old posts on prop guards not very positive. As the kids have now got some toys to tow this summer the wife thinks we should look at installing one. Has anyone been useing one or have any experance with them they could pass on.

Richard B · 31 May 2005, 13:39

I guess that your search threw up a potential performance loss...

Probably worth looking at the very well finished stainless steel guards that Thundercats use - obviously they want to minimise their performance loss!

Pete7 · 31 May 2005, 13:41

The Royal Navy diving club has a couple of Mariner 40s with them on. They turned a perfectly good planning inflatable boat into a 6 knot disaster. Huge loss in performance and they cost a fortune from Barrus (doesn't everything)

Understand your concern with the kids but in 20 years of diving I haven't seen a problem yet. A smokey 2 stroke tends to persuade individuals to stay away from the back of the boat before they get anywhere near the prop.

Run the engine out of the water and show the kids the prop moving round.

Pete

Jackwabbit · 31 May 2005, 14:03

We had 2 made up from stainless steel for our dive boats, they both run slower than before, and then one hit an underwater obstruction on the Thames while training new members. The result was the prop guard rapped itself round the prop breaking the gear casing, causing the inflatable to drift down the Thames in the fast running water.
Then a couple of years a go we got one of those plastic one’s that they advertise as improving performance. At low speed it did seem to be more directional but we didn’t see any improvement at higher speeds. Unfortunately we suffered another gearbox casing fail allowing salt water to get in & seize the gearbox.
Needless to say we haven’t fitted them since.

Neal · 01 June 2005, 17:59

Thanks all, looks like no real improvements in this matket. Think more training for the kids better option for now.

Simon B · 01 June 2005, 19:33

We had a prop guard of the tunnel/shulz nozzle type fitted, it was about £100 I think. It was smashed to pieces on rocks with only minor damage to the prop.

It did knock a lot of performance off. As as been previously discussed jets offer the ultimate in safety, a number of options exist for retro fitting a jet lower unit, however, one must bear in mind that a jet will lose 1/3 of its hp the Yam 80 is in fact the 115 or 100hp prop unit esteemed fora memebers will no doubt be able to recall this better than myself.

They also perform very differently in some sea states. If the benefits/features outwieghed the risks then possibly the RNLI would use jets they do not and do have rather a good record in rescue.

limeydal · 02 June 2005, 17:01

Hi Neal,
was looking at the same issue ,as my kids also love their donuts !
I also read negative feedback on guards and then came across this product.

http://www.westmarine.com/webapp/wcs...productId=1501

Supposedly the ring eliminates the "filleting effect" of conventional props and would seem to help in seaweed (big Kelp beds here).
Would seem to be a good compromise and claims"better performance'(of course)

Anyone had experience of these ??

cheers Dal

codprawn · 03 June 2005, 00:59

Quote:

Originally Posted by limeydal

Hi Neal,
was looking at the same issue ,as my kids also love their donuts !
I also read negative feedback on guards and then came across this product.

http://www.westmarine.com/webapp/wcs...productId=1501

Supposedly the ring eliminates the "filleting effect" of conventional props and would seem to help in seaweed (big Kelp beds here).
Would seem to be a good compromise and claims"better performance'(of course)

Anyone had experience of these ??

cheers Dal

Yes I have seen these as well - looks a pretty good idea but wonder how well iit will work???

limeydal · 03 June 2005, 05:40

Havn't seen them advertised for larger engines though and wonder if the ring just adds to the potential balance problems.
Seems you could get away with a small ding in a standard prop, but a twist or nick in the ring and the added mass on the outer edge could cause exagerated effects.
cheers Dal

Neal · 03 June 2005, 08:13

Dal I am going to RIBEX over the weekend will report back if I find further information.