Sardinia Summer 2015

[BartW]

.... As so many folks now have these I reckon you should get a "group buy" on upgraded consoles - this is a great improvement imho. Basically involves a tiny "shelf" created at the top of the angled face of the dash, so as to move the yam gauges and switches up , allowing room for colour plotter and other nav gear. And throttle stick moved back closer to helmsman. Was done by the GRP team at essexboatyards. ....

I see the improvements of your console, but I'm going to pass for that,
I didn't even install a plotter / depth sounder yet, still in its box for two seasons,
still many things to do or organise on the main ship that have much more use ...
such a upgrade has many more consequences/work than we initially think, including new cover, etc....

glad to hear the smaller prop is better, will upgrade mine, need a spare onboard anyway...

are you still without auto trimflaps, mine was delivered with the flaps installed FOC,
I believe they make a difference,
I remember you planned to design a hull extension ?

 

[BartW]

I think the problem is that none of the outboard manufacturers issue torque curves for their outboards, so we all end up choosing the maximum power to weight ratio rather than what really matters which is low down torque, which is much more dependant on cubic capacity. I assume you chose the Yam 70 because it only weighs 117 kgs? The thing is, it's light because it has a very small cubic capacity for it's power rating, 50% less than a Suzuki 70 for example, and only slightly more than the Suzuki 40 hp. Yamaha have been quite clever in designing outboards with high power ratings but small displacement and therefore low weight. A number of users then report that they're not very happy with the performance. I think we should all be looking at the displacement to weight ratio rather than power to weight. For sure, it's always then worth choosing the highest power rating using that block, but I think It would lead to different choices in some cases.

Yes Nick, I believe you're right on this,
I was surprised, but apreciate the choice you made for the etec on your sportfisher,
I must admid that I have never been a big fan of modern evinrudes for the noise they make.
I have a few friends with old ficht engines, and they sound like a sewing machine, but probably thats much better nowaday's?
Some time ago I drove a Suzuki OB Rib, and the noise from my neighbour ficht boat at 10...20m distance was more than the noise from the Suzuki on the boat I was helming !
only for that, I've alway's liked Suzuki OB's.

 

[jfm]

I see the improvements of your console, but I'm going to pass for that,
I didn't even install a plotter / depth sounder yet, still in its box for two seasons,
still many things to do or organise on the main ship that have much more use ...
such a upgrade has many more consequences/work than we initially think, including new cover, etc....

glad to hear the smaller prop is better, will upgrade mine, need a spare onboard anyway...

are you still without auto trimflaps, mine was delivered with the flaps installed FOC,
I believe they make a difference,
I remember you planned to design a hull extension ?

Hi Bart. Right now, I have nothing on the transom. I'm thinking of a hull extension, or interceptors, or flaps, but didn't get around to it yet. The hull extension would be nice but it is a big job to make moulds then make the extensions in GRP. Sometime, please can you post pictures of your flaps, including close ups

One problem I have with any mod apart from interceptors is that they interfere with my tie-down straps!

 

[MapisM]

what really matters which is low down torque, which is much more dependant on cubic capacity

Yep, but it's even more dependent on the engine cycle.
I mean, for any given displacement, 2 stroke engines are both more powerful and more torquey than 4 stroke - and also lighter.
We've been lead to think that 4 stroke was the be-all and end-all of outboards just because emission regulations became effective before direct injection technology was available, but nowadays, particularly for smallish O/Bs like those used in tenders, the choice between 2 and 4 stroke is almost a no brainer, imho.

 

[Nick_H]

Yes Nick, I believe you're right on this,
I was surprised, but apreciate the choice you made for the etec on your sportfisher,
I must admid that I have never been a big fan of modern evinrudes for the noise they make.
I have a few friends with old ficht engines, and they sound like a sewing machine, but probably thats much better nowaday's?
Some time ago I drove a Suzuki OB Rib, and the noise from my neighbour ficht boat at 10...20m distance was more than the noise from the Suzuki on the boat I was helming !
only for that, I've alway's liked Suzuki OB's.

I think the Etec are much quieter than the old Ficht engines, but still more noise than a four stroke. I really like the other features though, no servicing for 3 years and auto-winterise especially.

Having said that, I've spec'd a Suzuki on my new tender. It's slightly heavier than the equivalent HP Yamaha, but as per my comments above it has 25% bigger cubic capacity so should have much more torque. The Etec at this size was heavier than the Suzuki, and also has a smaller cubic capacity, so any extra torque from the 2-stroke will be offset by the lack of displacement. Suzuki was also offered at a keen price

 

[MapisM]

any extra torque from the 2-stroke will be offset by the lack of displacement.

Sorry if due to laziness I'm not googling for those O/Bs, but how much is the displacement difference, N?
Of course there are many other reasons why a model/brand can be better/worse than another, but when comparing 2 vs. 4 stroke on a (rather theoretical, I must admit) AOTBE basis, it takes a helluva displacement increase for a 4 stroke engine to achieve a torque/revving easiness comparable to a 2 stroke.
Probably in the +33% ballpark, if not more.

 

[jfm]

Merc/Yam (same powerhead) 996cc for the 50-60-70 hp. 4 cyl. (4 valve head in the 70)
Suzuki 941cc in the 40-50-60hp. 3 cyl
Evinrude 863cc in the 40-50-60. 2 cyl and 2T
Tohatsu 866cc in the brand new 50hp just announced. 3 cyl
Honda 808cc in 40 and 50hp. 3cyl.
Honda 998cc in 60hp 3 cyl and 4 valve head

The evinrude seems best for hole shot, said by a guy who bought Yamaha and thought it would be ok (which it is, except for hole shotting)

 

[Nick_H]

Sorry if due to laziness I'm not googling for those O/Bs, but how much is the displacement difference, N?
Of course there are many other reasons why a model/brand can be better/worse than another, but when comparing 2 vs. 4 stroke on a (rather theoretical, I must admit) AOTBE basis, it takes a helluva displacement increase for a 4 stroke engine to achieve a torque/revving easiness comparable to a 2 stroke.
Probably in the +33% ballpark, if not more.

I linked to a video on another thread where a Suzuki 40 holds it's own against an Etec 40 in a test of low down torque, with only a 9% bigger displacement, and a lighter overall weight, but in the same test the Yamaha 40 is out performed by a smaller Etec 30 despite having 35% more displacement. As you say, it obviously depends on lots of other things and the only way to know for sure is to fit the engine and try it.

Here's the video link again. Relevant bit is from 1:57: https://www.youtube.com/watch?v=tZvIw83uZgY

 

[Nick_H]

Merc/Yam (same powerhead) 996cc for the 50-60-70 hp. 4 cyl. (4 valve head in the 70)
Suzuki 941cc in the 40-50-60hp. 3 cyl
Evinrude 863cc in the 40-50-60. 2 cyl and 2T
Tohatsu 866cc in the brand new 50hp just announced. 3 cyl
Honda 808cc in 40 and 50hp. 3cyl.
Honda 998cc in 60hp 3 cyl and 4 valve head

The evinrude seems best for hole shot, said by a guy who bought Yamaha and thought it would be ok (which it is, except for hole shotting)

It would be really useful if engine manufacturers would release their torque/power curves, but it seems they are reluctant. In some cases the higher power variants of the same block also have more torque at lower rpm, but I don't know if this is always, or even usually, the case. I didn't know whether to order a 40 or 50 for my new tender, because I had no idea whether the 50 would give me more low down grunt, which I wanted, or just a higher top speed, which I didn't.

 

[MapisM]

Thanks jfm for the summary.
Just curious, are you just less lazy than myself (which ain't difficult, TBH ), or did you already prepare a comparison chart when you made your evaluations?

Anyway, without knowing anything else, I wouldn't hesitate one second to put my money be on the smaller 2T rather than the bigger 4T, in terms of torque.
The displacement differences are nowhere near enough to give 4T an edge, AOTBE.
N_H, re. your doubt, with a 4T engine, I'd expect the higher power version to deliver also more low rpm torque, but obviously I can't be positive on that.
I fully agree re. power curves, fwiw. 'Fiuaskme, it should be mandatory to disclose them!

 

[jfm]

Thanks jfm for the summary.
Just curious, are you just less lazy than myself (which ain't difficult, TBH ), or did you already prepare a comparison chart when you made your evaluations?

Anyway, without knowing anything else, I wouldn't hesitate one second to put my money be on the smaller 2T rather than the bigger 4T, in terms of torque.
The displacement differences are nowhere near enough to give 4T an edge, AOTBE.
N_H, re. your doubt, with a 4T engine, I'd expect the higher power version to deliver also more low rpm torque, but obviously I can't be positive on that.
I fully agree re. power curves, fwiw. 'Fiuaskme, it should be mandatory to disclose them!

Haha MapisM - that was a quick google while on a conf call!
The other thing to remember is that with higher HP people fit bigger props. The "right" prop on my novurania with yam 70 is a 16p, and it came with that. It gives great top speed but the holeshot is like trying to drag race in a station wagon in 5th gear. So I've gone down in pitch to 14, 4th gear rahter than 5th, so throwing away the top speed benefit of 70hp, but got better low down performance. Still not drag race stuff, but much better.
And then the other thing is people. With one person only my yam 70/novu is very fast. But put 5 or 6 people in it and everything is different. Alas you have to pick one prop, and so you make compromises. I often have plenty of people in mine and might even buy a 12P prop (3rd gear) and just live with the lack of top end speed. It would be great if they could install a little 2-speed epicyclical gearbox just under the powerhead

 

[MapisM]

might even buy a 12P prop (3rd gear)

Have you ever considered this option?
http://propulse.se/en/
On paper, with one of them, a full gear choice should be right at your fingertips...

 

[davids0865]

Have you ever considered this option?
http://propulse.se/en/
On paper, with one of them, a full gear choice should be right at your fingertips...

Very clever...................

 

[BartW]

Have you ever considered this option?
http://propulse.se/en/
On paper, with one of them, a full gear choice should be right at your fingertips...

many years ago I tried one of these on a 6m sport fisher V6 Merc alfa drive, and the performance was nowhere near a Original Mercruiser prop,

 

[MapisM]

B, I've been told that up to 100hp or so the efficiency difference is not much, and well worth accepting to get the pitch adjustment, anyway.
Not my first hand experience I must say, but the guy who told me about these props normally knows his onions, and has no reason to be biased.
Otoh, It's easy to guess that if you're after squeezing the max top speed out of an engine, nothing can beat a "normal" prop (or even better, a s/steel one), but as I understood, that's not what jfm is interested in...

 

[BartW]

B, I've been told that up to 100hp or so the efficiency difference is not much, and well worth accepting to get the pitch adjustment, ...

yes my experience is also very limited, and on 200Hp engine only,
at the time (2004 iirc) I had a old slightly damaged prop on the boat, so I ordered that propulse prop, and we used it for a while, and that was OK,
changing the pitch was quite a hassle so we only did a 2 or 3 times iirc

then during the holiday we touched ground, and damaged two blades, and went to a local Chandler,
he had the blades / propulse prop in stock, but adviced us to go for a Original merc prop, which we did, (he might have had some commercial incentive also )
This prop had blade cupping compared to our old that didn't, and the boat worked better than ever before,
I mean, accelaration, going on the plane and pulling toy's, without cavitation nor ventilation...
we were never looking for higher speed
that was the first time I had experience with prop blade cupping,
and realised how important it is to have a impeccable prop

 

[Hurricane]

OK - so what does the panel think about these engines?
http://yamahaoutboards.com/outboards/High-Thrust/overview
I did a little research and it seems that, essentially, they are geared differently.
It looks like Yamaha designed them for the heavier boat but maybe they would perform better at the lower speeds.
I came to the conclusion that it would be safer to stick with a standard engine.
(see - a new dinghy is getting serious now)

 

[jfm]

Hurricane I think the high thrust yam f50 and f60 are the same engine as the normal 50/60 but with the bigger gearbox added (2.33:1 ratio, and 4 inch hub dia, or maybe 4.25", instead of the 3.5 inch hub dia on standard f50/f60) and -according to your link- some details like a less ventilating propeller. Designed for heavy/slow boats.

The 70 yam already has that 4inch gearbox fitted, so it doesn't/can't come in a "high thrust" variant. So you might as well just buy the 70 imho

Props are a bit of a black art and at ~ £150 each you cant keep trying different ones as a leisure boater. I'm firm that the 14inch pitch yam works better on the Novu than the 16inch, but there could be other better props out there. MapisM thank you for the propulse link - I struggle because they are (for my o/b) €300 and the pitch range on model 8902 is 15-21P whereas I want say 12-16P. Meanwhile a yam fixed prop is only £130 http://www.ebay.co.uk/itm/Yamaha-Ge...e-K-14-x-11-/140759731637?hash=item20c5ef0db5. Also, it is an easy job to throw a 12 or 13P on for waterskiing, so it needs to be VERY easy to change the pitch on the propulse to beat that in terms of hassle/effort

Hurricane, for the yam f70 you need a "type K" prop. This defines the number of splines and hub diameter, and I suggest you should use type k when internet/ebay searching. I think the f50/60 use type J but I'm not 100% sure

 

[Hurricane]

Hurricane I think the high thrust yam f50 and f60 are the same engine as the normal 50/60 but with the bigger gearbox added (2.33:1 ratio, and 4 inch hub dia, or maybe 4.25", instead of the 3.5 inch hub dia on standard f50/f60) and -according to your link- some details like a less ventilating propeller. Designed for heavy/slow boats.

The 70 yam already has that 4inch gearbox fitted, so it doesn't/can't come in a "high thrust" variant. So you might as well just buy the 70 imho

Props are a bit of a black art and at ~ £150 each you cant keep trying different ones as a leisure boater. I'm firm that the 14inch pitch yam works better on the Novu than the 16inch, but there could be other better props out there. MapisM thank you for the propulse link - I struggle because they are (for my o/b) €300 and the pitch range on model 8902 is 15-21P whereas I want say 12-16P. Meanwhile a yam fixed prop is only £130 http://www.ebay.co.uk/itm/Yamaha-Ge...e-K-14-x-11-/140759731637?hash=item20c5ef0db5. Also, it is an easy job to throw a 12 or 13P on for waterskiing, so it needs to be VERY easy to change the pitch on the propulse to beat that in terms of hassle/effort

Hurricane, for the yam f70 you need a "type K" prop. This defines the number of splines and hub diameter, and I suggest you should use type k when internet/ebay searching. I think the f50/60 use type J but I'm not 100% sure

I remember doing just this on our current "over engine d" Walker Bay / 40HP Yam.
I reduced the pitch by a couple and it did seem to give it a bit more performance at the lower speeds (better for skiing) - never went back to the original one - top speed is mad on that little boat anyway.

 

[MapisM]

M, any reason for sticking to Yam 4 sroke?
I for one wouldn't rule out the 60hp E-TEC.