Vipermax down under

Apherel · 25 August 2008, 12:34

Delighted with the boat, especially in the rougher stuff - of which there are no pictures, however here are some recent shots from a cruise up the Yarra river. We took a group of 10 year olds for a birthday party upto the city, then up river where they were collected. Fabulous day. Evening trip down stream was spectacular as evening fell.

Apherel · 25 August 2008, 12:37

and back home - all at 5kn speed limit so very tranquil.

Apherel · 25 August 2008, 12:45

These shots are on Port Philip Bay.

Downhilldai · 25 August 2008, 13:28

Nice!
What max speed do you get out of her?

Apherel · 25 August 2008, 13:55

Not quite as fast as I'd hoped.

Around 35 kn. In retrospect (and acknowledging the advice on the forum) a 150 hp would have given more hooning opportunities and I'd definitely go for a 150 if making the choice again. Having said that, the DF 140 is more than adequate in anything except a flat sea and cruises very comfortably in our local choppy seas.

Downhilldai · 25 August 2008, 14:04

They're not the fastest hull around, but I thought you would hit more than 35kt. What prop are you running and what max rpm are you hitting?

Apherel · 25 August 2008, 14:11

Yes I did too, the boat was much heavier than I'd expected. I'm using the standard suzi aluminum 21x14 inch. I've tried the 19 inch & this is better. Revs to 6100, just under the 6200 rpm max.

Talked with the suzuki dealers about a stainless 22 inch, but they don't think it will make much difference.

So unless the engine is not powering up correctly, I'm at a bit of a loss.

Downhilldai · 25 August 2008, 23:23

This thread may be of some use:

http://rib.net/forum/showthread.php?t=13500

It's a Ribcraft, but same size and same motor.

Ian Sharlot · 26 August 2008, 08:11

Quote:

Originally Posted by Apherel

Not quite as fast as I'd hoped.

Around 35 kn. In retrospect (and acknowledging the advice on the forum) a 150 hp would have given more hooning opportunities and I'd definitely go for a 150 if making the choice again. Having said that, the DF 140 is more than adequate in anything except a flat sea and cruises very comfortably in our local choppy seas.

Top Banana has a 5.8 Osprey with a 135 opti and gets 42-44 knots I think. Nice boat.

Top banana · 26 August 2008, 14:19

Quote:

Originally Posted by Ian Sharlot

Top Banana has a 5.8 Osprey with a 135 opti and gets 42-44 knots I think. Nice boat.

yes Ian thats correct, with 150ltrs, and four adults, with a frame and aux 6hp
42 knots, going 44 running lighter. I do remember your thread about which engine to go for, as said my last rib was a shakespear 6.2 with a 140 suzuki
and only managed 37 knotts whatever i did.And the shakespear was a lighter boat. So you may not be that far away from your top end. you could try lifting the engine up a hole, or join the optimax brigade

Hightower · 26 August 2008, 18:44

Vipermax 6.2 with Rude DI 150 with a WOT speed of about 39 knotts with a 19" prop.

I too was a little disapointed, but nearly always run with over 100 litres of fuel on board and I guess she has had a few pork pies stowed away

.

Apherel · 26 August 2008, 22:47

Thanks for the comments - I'm having trouble understanding how the Suzuki 140 would produce such a different top end from the opti 135 - hole shot or acceleration I could imagine - but nearly 10 kn difference in top speed??

Over the next few weeks I'll get a diagnostic run on the engine, check the height (which I think is OK), weigh the boat, see how it runs with a lighter load then think about trying a stainless prop.

Any other ideas greatly appreciated.

Downhilldai · 27 August 2008, 00:43

135 Opti is a 2.5 litre, V6 2-stroke (de-tuned 175hp)

DF150 Soozook is a 2.9 litre in-line 4cyl, 4-stroke. (de-tuned 175hp)
DF140 Soozook is a 2.1 litre in-line 4cyl, 4-stroke.

Some say Soozook brought out the DF150 'cos the DF140 can't produce the full box of horseys.

Apherel · 27 August 2008, 02:11

Ok I didn't realise the opti was a V6. I'm aware of the chatter about the DF 140 output, but I thought that had been disproved, although having a quick look on the web I couldn't find anything definitive.

Did find some comments that the setup is pretty sensitive to props and needs to be mounted with the cav plate 2-3 inches above the bottom which seems a bit higher than other setups.

Also seems that many people feel the need to run them near WOT, which is OK 'cause they are quiet, economical and have a 5 year warrantee.

But I'm getting a pessimistic feeling that I'm going to get a lot more from it.

Hightower · 27 August 2008, 17:03

I too had heard of Suzuki's being a little bit opimistic on the engine badge for the 140. But on the opposite side of things the Evinrude bought out the HO brand that offers something above the quoted HP.

Wonder what the limits are in HP difference you need to comply with advertising, trade description etc?

Apherel · 27 August 2008, 21:47

And under what conditions - I doubt that they would be allowed to market it with a major difference (I read somewhere it was less than 6%), and they supposedly all have to be tested under the same conditions.

Top banana · 27 August 2008, 22:18

forgot to mention. im not running at max rpm yet, got to try and squeeze another 400revs somehow

Apherel · 27 August 2008, 23:26

Quote:

Originally Posted by Top banana

forgot to mention. im not running at max rpm yet, got to try and squeeze another 400revs somehow

Hmmmmmm

Hightower · 28 August 2008, 00:21

Quote:

Originally Posted by Top banana

forgot to mention. im not running at max rpm yet, got to try and squeeze another 400revs somehow

Yeh, but you might not get any more speed! I assum you're going to find a prop to give you those extra revs?

Downhilldai · 28 August 2008, 00:27

Quote:

Originally Posted by Top banana

forgot to mention. im not running at max rpm yet, got to try and squeeze another 400revs somehow

Mine's the same - most I've seen is 5200rpm