Trialing new F70 Yamahas on my 5.2m Kevlacat

[Dean1]

Just saw a 5.2 Pro Sport with new 70 Yam 4 bangers at Gav from Victory Parts.

Ah i must give Gav a ring then! Funny character he is Cheers for that Smithy.

No nothing happning yet Dan weve both been too busy..

[Grouse]

Pretty impressive demo on the TV show today. Two 70's on a 620 barcrusher getting above 60kph. Then on one leg, out of the water and just over 40kph.

[Salad Fingers]

Pretty impressive demo on the TV show today. Two 70's on a 620 barcrusher getting above 60kph. Then on one leg, out of the water and just over 40kph.

I don't get it? whats so spesh about that?
a 6.2m alloy boat with 140hp doing 60kmhr is pretty normal.
I'll bet they couldn't get it to hop up onto the plane and achieve 40kmhr only using one engine from a standstill though?

Two Yammy 70's is what? 240kg?
One Suzuki 140 is 185kg or thereabouts.

.....

[Grouse]

I'll bet they couldn't get it to hop up onto the plane and achieve 40kmhr only using one engine from a standstill though?

Two Yammy 70's is what? 240kg?
One Suzuki 140 is 185kg or thereabouts.

.....

Pretty sure that's what they did, that's what is "spesh".

If had an offshore boat, I would like two donks, not one.

[FNQCairns]

They had 3 blokes and a full tank of fuel too, it planed in dead calm water from a standstill on one engine...was a job well done i thought, of coarse it took ages to get there.

The engines where meeting the high end of the rpm range, think they said the boat could see 6300RPM, probably wouldn't have made it onto the plane on one engine if it where only seeing 5900.

[Salad Fingers]

Ok well thats special then, i'll pay that

[saltchaser]

Those new 70s got that barcrusher up and runnin.

[kitty_cat]

hey dean might be a good oportunity to get the 2 boats out together it would be interesting to see how they sit in the water side by side and performance ect
will you get to use them without the yamaha guys around not sure how they would react to a suzuki yamaha meeting.
pretty keen to tee this up plenty of guys looking at repower and could be a good pro cons list to be made.
wayne

[Smithy]

So this is the scoop on Gav's one from my mobile outboard mechanic who is pretty tight with Gav. Not a whole lot of difference to the 60s of course cause it is essentially the same motor with different porting/exhausting and all that to ring the extra 10hp out of it. The big thing my guy reckons is the new sumps are only about 1.5litres of oil to keep the weight down and leave more room for the exhaust and with about 1.0l of oil circulating through your moving parts at any given time it doesn't leave a lot spare. Dunno what engine life is going to be like. Little increase in top end speed and it can punch through waves a little bit better without having to play with throttles but certainly not worth the extra $$$s over the high thrust 60s which are significently cheaper.

[Grouse]

Also just noticed a new power report for a twin Yamaha F70A

http://www.yamaha-motor.com.au/sites...%20F70AETL.pdf

[FNQCairns]

Just looking at grouse's link above and I came to the conclusion that the twin 70s on that boat don't actually work very well, IMO would probably be a poor choice relative to what other choices are available.

[Grouse]

Just looking at grouse's link above and I came to the conclusion that the twin 70s on that boat don't actually work very well, IMO would probably be a poor choice relative to what other choices are available.

Yea I'm a little confused at those results as well. I'm sure when I watched the Hook Line & Sinker barcrusher demo, they said they had a 15" prop, not a 13 1/2" dia. Maybe he was talking about the pitch? I need guidance when it comes to props. Is there such thing as a 15" dia prop for that size motor?

[FNQCairns]

Here we go this makes fishing boat mash meat out of the twin 70s for the HP available.

http://www.yamaha-motor.com.au/sites...Cuddy_F115.pdf

Grouse true, when I heard that I also wondered and decided they must have been talking 15 inch pitch like you say, 15 diameter just doesn't work unless the pitch was 13 or so...also they said it was a stainless....not that that actually makes any real difference on fishing boats.

[black runner]

Just read the Vindicator test in F&B and while the speed figures weren't anything exceptional, the twin setup held plane down to 10-11 knots, with plenty of grunt/prop grip to hold it there in rough conditions without dropping into the hole.

I suppose this would apply with the 60 as well.

Cheers

[Noelm]

Pretty sure that's what they did, that's what is "spesh".

If had an offshore boat, I would like two donks, not one.

so you don't suppose they did a quick off camera prop swap then? even if the twins could achieve 6,300RPM I would guess that the prop would be too big on a single to plane ,but not impossible (maybe) given enough time and if you dont care about the engine at all.