which prop? - Page 2

Chris · 20 June 2009, 00:17

Quote:

Originally Posted by Tarbh

I've just checked and my prop is actually a 19 Viper!

Based on that, would a 21 Viper be my best option?...

Yes

If the 21 works out for you and you decide you don't need the 19" I would take it as a spare.

Chris

Maximus · 20 June 2009, 09:55

Quote:

Originally Posted by humper

Hi, I have recently launched my new boat. Vipermax 7.5 with 250 etec. I wanted a 23" prop as I had this set up on my 7m Vipermax/250etec.and it proved to be a great all rounder. It was good out of the hole but could sometimes slip a bit.Top speed was good at 59mph.Ecomony was very good as we regularly saw around 1mile/litre when crusing. The trouble is the new etec has come with a 21" viper prop and 23" vipers are very hard to come by.
My engine supplier is being very helpful and has offered me various alternatives. A 23" 4 blade, a 22" viper or a 24". The 24" has to be rejected because of the potential slip problem.so it comes down to the 4 blade 23 or a 3 blade 22. I have got no experience of 4 bladed props so am struggling to reach an informed decision.The trouble is that I can`t try the 23/4blade as this will then become a used prop if I don`t like it and the dealer will lose out.I am tempted to go for the 22. Has anyone got an opinion on my choices?
Thanks

Your dealer seems a bit 'reluctant' to me Humper,recently bought a new e-tec from Race Marine and he gave me no fewer than four props to try!The difference was notable dispite what some of the 'worthys' on the Forum had to say,although I see it did'nt stop them from experimenting!ha!If you read through the manual which comes with the engine it recomends you to try as many props a you can,so who is going to supply them if not the dealer?who has just relieved you of several grand by the way?? Maybe I was lucky,maybe someone is being less than helpful.[And yes all the props were brand new!]

Mollers · 20 June 2009, 13:42

Quote:

Originally Posted by Maximus

Your dealer seems a bit 'reluctant' to me Humper,recently bought a new e-tec from Race Marine and he gave me no fewer than four props to try!The difference was notable dispite what some of the 'worthys' on the Forum had to say,although I see it did'nt stop them from experimenting!ha!......

So do your '30+ years' of experience make you the most 'worthy' of them all?

Poly · 20 June 2009, 20:47

Quote:

Originally Posted by Maximus

And yes all the props were brand new!

before or after you used them

Mollers · 20 June 2009, 23:56

Quote:

Originally Posted by Polwart

before or after you used them

A call might be in order for a deal on a used prop.

Downhilldai · 21 June 2009, 00:04

Quote:

Originally Posted by Maximus

.... he gave me no fewer than four props to try!The difference was notable ....

What props did you try and what differences did you note?

Chris · 21 June 2009, 08:07

I can answer this one as I was the one who helped test them.

Viper 17" (std) - 5950 RPM, 42 knots
Aluminium 19" - 5700 RPM, 44 knots
Raker 20" - 5600 RPM, 46 knots
Raker 22" - Did not test, no point.

Chris · 21 June 2009, 08:18

What we need is a website where you can hire different props to test with a view to purchase. A nice business idea if set up right, surely.

You could make it interactive by typing in your current performance, prop and boat details the website then fires back a couple of suggestions for you to try.

Hmmm

Maximus · 22 June 2009, 22:51

Quote:

Originally Posted by Downhilldai

What props did you try and what differences did you note?

Chris was about right DHD,although with the standard 17'' Viper only managed around 40knts,and I JUST HAD TO to better Matt h in his 'Sea Rider,'or I'd hear him gloating ....over the engine!!

blufin · 23 June 2009, 13:29

hi chris/maximus
just wondering what your thoughts are on the raker versus the viper..overall perf., grip, hole shot etc.
ta gerry

Chris · 23 June 2009, 21:51

Quote:

Originally Posted by blufin

hi chris/maximus
just wondering what your thoughts are on the raker versus the viper..overall perf., grip, hole shot etc.
ta gerry

Hi Gerry,

The experience I have had tends to suggest the Raker grips slighty better and will potentially give you a marginal improvement in Speed whilst losing a few RPMs. you can generally recover the RPM by making sure you have the vent plate riding on top of the water whilst on the plane, which is how any e-tec should be set to achieve best results.

If you are going to change fr om a Viper to a Raker I would recommend lifting the engine at least one notch.

I have not yet tried a Raker on my 150 but would be interested to compare results against the 19" Viper although I am pretty happy with the Vipers perfomance, its a good all rounder IMO.

Cheers

Chris

blufin · 03 July 2009, 13:56

cheers for that chris. its what i was hoping you'd say. my engine is quite high and the viper struggles a bit so the raker sounds like an option...now has anybody got a 23" raker they'd like to sell.
thanks again gerry

Chris · 05 July 2009, 17:45

Quote:

Originally Posted by blufin

cheers for that chris. its what i was hoping you'd say. my engine is quite high and the viper struggles a bit so the raker sounds like an option...now has anybody got a 23" raker they'd like to sell.
thanks again gerry

Gerry, have a chat with Roy Bishop I believe he had a couple of spare props knocking about. If not he is able to get good deals on new ones.

Maximus · 05 July 2009, 20:38

Quote:

Originally Posted by blufin

hi chris/maximus
just wondering what your thoughts are on the raker versus the viper..overall perf., grip, hole shot etc.
ta gerry

Hi Gerry,just got back from great weekend in The Solent so did'nt see your post,personaly think the Raker has the edge top end [slightly] over the Viper,but hole shot may suffer a little,grip excellent...one thing worth bearing in mind though is the Raker is a very fine bladed prop,and as a consequence ALOT more susseptable to damage than say the much chunkyer,thicker bladed Viper.