Which prop???

[Stephan]

I read about different props constantly but don't know waht difference it makes.

What is the best on my 580 deep V with my Yam F100. I mostly cruise with my wife and little son. I don't even know what prop I have at the moment for I bought it like this. It planes quickly but it feels like it could go faster. At 5000rpm it goes about 50-55 km/h. Is that normal?

[Noddy]

Hi Stephan
Do what I did -Pm Julie from Steele Developments(SteelDev on here) tell her your current prop size and she will advise you - she knows her subject!
Your current Propellor Size should be stamped on one of the blades.
regards
Martyn

[timboli]

Originally Posted by Stephan

I read about different props constantly but don't know waht difference it makes.

What is the best on my 580 deep V with my Yam F100. I mostly cruise with my wife and little son. I don't even know what prop I have at the moment for I bought it like this. It planes quickly but it feels like it could go faster. At 5000rpm it goes about 50-55 km/h. Is that normal?

I have a similar set up to you,I have a 21 inch prop,the engine pulls 5700-6100 dependant on trim(up at the front equals faster but more unstable) and around 48mph (40 knots)max,I also usually cruise with my wife and son.
I am waiting for my dealer to get the next size prop bigger(more pitch) to try as I feel I would like to cruise at lower revs,and would be interested to know if this increases top speed.
I find the engine relatively rough at 3000-3500 revs(just on the plane) so also want to see if i can plane at lower revs(out of the rough zone).
One thing to bear in mind is that if you pull skiers,the engine will struggle more with a larger prop.
Yamaha advised me against a stainless prop as if you hit something,it is more likely to damage the gearbox as stainless is stronger then alloy.
If 5000 is your max revs,you could be overpropped as max power is developed at 5500
Let me know how you get on if you change the prop please

[Stephan]

Originally Posted by timboli

I have a similar set up to you,I have a 21 inch prop,the engine pulls 5700-6100 dependant on trim(up at the front equals faster but more unstable) and around 48mph (40 knots)max,I also usually cruise with my wife and son.
I am waiting for my dealer to get the next size prop bigger(more pitch) to try as I feel I would like to cruise at lower revs,and would be interested to know if this increases top speed.
I find the engine relatively rough at 3000-3500 revs(just on the plane) so also want to see if i can plane at lower revs(out of the rough zone).
One thing to bear in mind is that if you pull skiers,the engine will struggle more with a larger prop.
Yamaha advised me against a stainless prop as if you hit something,it is more likely to damage the gearbox as stainless is stronger then alloy.
If 5000 is your max revs,you could be overpropped as max power is developed at 5500

Thanks Timboli.

Unfortunately is my Dutch better than my English so I can't understand everything. I'm also not a specialist in "rib- and propthings". I can not read the size of the prop which is fitted now but the seller gave me another one which looks heavier and is bigger. It is an: 12 5/8 * 21-K and I don't exactly know what it means. Maybe it will go faster if I fit this one. (By the way: is it easy to change a prop??)

At the moment I'm very quickly in the red zone with my revs (about 6000). Like you I prefer a higher top speed. My top speed is about 35 mp/h and I think it's too slow for a rib like mine. I tested it on flat water with no other person in it. That's like a snail comparing to your 48 mp/h.

I hope you know the answer. Thanks in advance.

Regards from Maastricht,

Stephan

[timboli]

Stephan,
I dont know if the diameter is the same but my current prop is a 21k,are both props in good condition as I have heard that damaged props will affect performance,does trimming the boat up more at the bow make any difference,is the engine cavitation plate on the same level as the bottom of the hull,if it is lower,it could slow you down,beware that raising the engine so that the cavitation plate is above the bottom of the hull may increase speed but could also cause the prop to lose grip on the water.
My boat is around 350kg without the engine,tank and any kit,do you have a lot of kit stored on board,check if there is any water trapped in the area between the deck and the hull.
If all else fails contact your local yamaha dealer,he should be able to tell you what prop is on there if you show it to him.
I dont know much about bombards,it may be that the design speed is low although I believe they are quite light(weight) from the factory.
I may be wrong but I think I had a Bombard brochure about a year ago which told you what speed each model was capable of with the max rated horsepower.It may be worth visiting a Bombard dealer and getting a brochure.

[Stephan]

Do what I did -Pm Julie from Steele Developments(SteelDev on here) tell her your current prop size and she will advise you - she knows her subject!

Hi Noddy,

Sorry I didn't react earlier. Who is Julie and how can I contact her.

Is it easy to change the prop myself? Than I can sea the size of my current prop. I know the spare one is a 21k.

And Timboli: I'll let you know how the 21 handles compared with the one that is fitted at the moment. I'll go to Spain the 1st of july and will change the prop first. It's not relaxed to cruise at 5000 revs and about 34 mph.

[Neal]

I think this is what you need www.steeldevelopments.co.uk

Neal