1st Hand Advise Needed - Fazer 170 Boat (somewhat urgent)

[Morne - Skip]

I don't think you could go wrong with this, I have this exact same rig, hours probably about the same. The difference between the 115HP & 130HP engines is purely that the 115HP version uses a carburetor while the 130 is fuel-injected.

With 2-5 people on board, I never once battled pulling any skiers, slalom or not, never even entered my mind that I could not and simply floored the throttle and away we went. This was at our local Dam and also at the Vaal River Boating Club, near Orkney.

Sadly, for various reasons I have not touched my boats for 6 years now, they are parked here at home and I sold my cottages at the boat club.


-F_D

Please be sure to save my number, if ever you want to sell the Fazer .... please

[Petri Oosthuizen]

It depend what fins you speak of. There is the Hydrofoil that fits to the lower unit of the motor, I don't like these as they put strain on the motor mounts etc. You get the Trim Tabs which most definitely work. These are installed on the transom at the bottom. They made a really big difference on my old boat and WILL buy then again for the new boat.

Further to Koebelwagen's post, most importantly when you have the WOT speed, the gearbox ratio and the propeller size you can measure the "slip". As he said not all prop's are equal, some are cupped for better efficiency etc, etc. So the slip is the difference between the theoretical speed and the actual speed as the prop has cavitational losses.

Theoretical Speed = Motor rpm / Gear Ratio x Prop Pitch. So lets assume 5 500rpm, 2:1 Gearbox ratio and a 17" pitch or 431.8mm pitch or 0.4318m pitch.
5500/2*0.4318 = 1 187.5m/min or 71.25km per hour

if you only actually get say 60km/hour then the slip of the propeller is ((71.25km/h/60km/h)-1)x100 = 18.75% there are props at 5% slip.

So now you can try different props and the ones with the lowest slip will have the best hole shot.

Stainless props have less slip than die cast aluminium props.

Thanks again, I'm learning a TON here.

Trim tabs......?? But I'll Google anyway. I was talking about those hydrofoils, but dunno - I guess they may work, but my (limited) boat logic also says they may make a boat a but unstable maybe?? My old believe.......if they were that great, the outboard manufactrers would have made them like that, or at least as an approved accessory.

Just curious - why is there less slip on alu than cast props?? Do the steel ones "bend" a bit at speed?

Anyway - the Bootjie (the Kids call her " Fazey ") is all cleaned up and polished nicely, upholstery is squeaky clean, and yes.......still VERY chuffed this side!!!

[Andrew Leigh]

Thanks again, I'm learning a TON here.

Trim tabs......?? But I'll Google anyway. I was talking about those hydrofoils, but dunno - I guess they may work, but my (limited) boat logic also says they may make a boat a but unstable maybe?? My old believe.......if they were that great, the outboard manufactrers would have made them like that, or at least as an approved accessory.

Just curious - why is there less slip on alu than cast props?? Do the steel ones "bend" a bit at speed?

There is more slip on Aluminium. SS is tough and does not flex that readily. Plus the blade thickness is much thinner allowing the blades to cut into the water easier than aluminium.

Anyway - the Bootjie (the Kids call her " Fazey ") is all cleaned up and polished nicely, upholstery is squeaky clean, and yes.......still VERY chuffed this side!!!

Nice name for the boat.

[Koebelwagen]

SS is tough and does not flex that readily. Plus the blade thickness is much thinner allowing the blades to cut into the water easier.

May I just add stainless props come into their own on motors with more than 100HP and excel in motors with 200HP+ but again don't just fit a stainless prop for the sake of the material, the blade design remains critical.

Take my boat and that of my father. Both bass boats, both with 70HP Yamaha motors. Mine is 16Ft and his 14Ft but mine is slightly narrower than his and both weigh within 20Kg of each other dry.

I bought mine with a Solas stainless prop and he had the standard Yamaha unit on his boat. My boat can do 60KM/H GPS speed which is very fast for the combination and the fact I weigh just about twice as much as my dad whilst his boat could do only 55KM/H so he decided to fit a new prop to his boat. First thing he did was order a stainless steel Solas/ Rubex unit with the same pitch and diameter and it was a disaster due to a different design of the blades, his boat was not only slower but it also took much longer to get onto plane because the motor simply doesn't have the power to swing the much larger profile blades.

Then he tried an aluminium Rubex with a more aggressive pitch but far less aggressive blade and it only just worked when he was alone in the boat but put two people into it and it would bog down. In the end a different aluminium Yamaha prop with the same pitch and similar blade design as the unit on my boat worked the best and his boat can now also run 60KM/H GPS speed. Incidentally the aluminium Yamaha prop that ended up being the best was also the cheapest by some margin, as in R2 200.00 VS R5k+ for the Stainless Solas.

I would really recommend trying out a few different models of prop if you are able to. You might find the standard unit is best.

[Petri Oosthuizen]

Koebel - thanks.

The kids is riding that boat to pieces

Jokes aside......once again, we're VERY happy with it (OK they - I haven't had a chance to skipper it since).......and that little 115 actually managed to pull Jomar (114kg) out with a start slalom.

Not easy, its not as if Jomar popped out, but it gets him out, and maintains a 50/52 km/h easy peasy, with room to spare. Sev (95 kg) and the girls gets out with a slalom easy peasy.

Pappa sal nog probeer........maar eers later, Pappa braai en drink nog eers op die wal Jack en bestudeer eers alles

This was with 4 others on board.

And, so far, I've decided to just stick with what's on it - the standard 17' 3 blade. Current one is quite chipped and has a little "tear"in it, so I will definitely get a new one, though - and just keep the old one as "spare".

[Family_Dog]

Glad you're enjoying it, Petri, the Fazer/Yamaha 115 combo just works. Can't remember what prop is on mine, but it has coped extremely well with whatever I throw at it. If I remember, I will take a look later today.


-F_D

[Petri Oosthuizen]

FD, ja - soos ek se die prop is nie mooi nie, ek sal hom moet replace.......maar ek het nou al met BAIE okes gepraat oor sizes etc etc:

1) Die 4 blade is nice(erig), maar op 'n 115 moet ek nie verwag dat hy gaan barefoot nie.
2) 15' maak verskil uit die pot uit, maar enjin rev redelik meer as met die standaard 17
3) 19' gaan revs drop, dat die enjin se optimum range dan dalk "uit" gaan wees.
4) S/Steel props kom in gelyke pitch nommers....maar daar moet maar baie water innie see loop voor ek R 16000 betaal vir een.

.....Meeste okes se hou by die standard, 3 blade, 17'. Ek dink ek gaan maar een kry, en so met die tyd sal ek pelle se 4 blades etc etc etc leen en kyk hoe groot verskil maak dit rerig.

[Andrew Leigh]

S/Steel props kom in gelyke pitch nommers....maar daar moet maar baie water innie see loop voor ek R 16000 betaal vir een.

Jy kyk in die verkeerde plekke.

4 blade prop 15 (dogfishmarine.co.za) OK so it is not SS but at R 1950, and add another R 950 for the prop hub kit this may well be worth your while.

[Petri Oosthuizen]

Jy kyk in die verkeerde plekke.

4 blade prop 15 (dogfishmarine.co.za) OK so it is not SS but at R 1950, and add another R 950 for the prop hub kit this may well be worth your while.

Andrew BAIE dankie!!

.....Wat sou jy gedoen het? 15' 4blade, 17' 4 blade of hou wat hy nou is?

Ek MOET anyway 'n ander prop koop.

En dan, daai "Rubex" props - is hulle maar dieselfde as die OE Yamaha??

DANKIE WAARDEER

[Andrew Leigh]

Ek dink die beste is om vir hulle te bel.

My mening is dat n 15" 4 lem prop sal werk.

[Petri Oosthuizen]

Andrew..........LAASTE vraag asb

Drop RPM op 'n 4 blade??

Maw sal die RPM van 'n 4blade drop teenoor RPM van 3 blade, selfde pitch??

Indien wel - RPM op 'n 4 Blade 15 is dan naastenby selfde as op 'n 3 VBlade 17??

BAIE DANKIE en jammer vir al die vrae

[Koebelwagen]

Petri,

Gaan na hierdie link: http://www.yamahapropselector.com/pr...web/inner.html

[Andrew Leigh]

Andrew..........LAASTE vraag asb

Drop RPM op 'n 4 blade??

Maw sal die RPM van 'n 4blade drop teenoor RPM van 3 blade, selfde pitch??

Indien wel - RPM op 'n 4 Blade 15 is dan naastenby selfde as op 'n 3 VBlade 17??

BAIE DANKIE en jammer vir al die vrae

Die oppervlakte van the 4 blade is meer so n 17" pitch 4 blade sal drop teenoor n 17" pitch 3 blade. Ek sal skat dat n 15" pitch blade omtrent die selfde sal wees as n 17" 3 blade.

Ek vermoed dat n 16" pitch 3 blade vir jou gaan werk and sal die velige opsie wees.

Wat is jou max rpm met die 17"?

[Family_Dog]

Petri,

This is the standard prop that I bought with the boat, works very well and handled everything I expected it to. Three blade, 13 x 19-K.


-F_D