New Ribcraft - DF175 Suzuki Prop

[dwalters]

Hi.

Firstly, I picked up my new Ribcraft 6.5 last week, which as expected has been fantastically built by the guys at Ribcraft. Many thanks to all them for producing such a good boat.

Following the run in at the weekend, I got the opportunity to give it full chat for a few minutes. The boat has a Suzuki DF175 on it which has a max rev range of 5,500 to 6,100 rpm.

On the run my boat max'd out at 4,800 rpm and 38 knots (SOG). Whilst I am not usually concerned about top speed, I do beleive this is considerably less than what the engine is capable of. Does anyone have any comments about whether this is just a prop change or something else (I am afraid I forgot to look at what pitch I was running).

Thanks

[TNDB]

Nice rig
I have a new DF150 on a Rib-X 640 which runs a Suzuki SS 3 X 15 X 21pitch prop and manages 43knots at about 6200rpm.

Realising that 6200rpm is pushing it a bit for the DF150 (operating range 5000-6000rpm) I have puchased a Solas Lexor 14.75 X 23pitch and am hoping this will drop me back to around 5800rpm.

The DF175 has the higher lift cams in it with the extra 25hp coming in above 5500rpm so to get the benefit of your higher rated motor you need to get it propped right, acceleration will also benefit from a prop which will take you into the full power zone.

[IBWET]

Firstly best of luck with your new boat,i picked a 5.85 up from RC last september,the boat has more than compatently handled all I've asked of it,
I have a DF150, ultimately end up with a 25" with the boat doing 46knots at5,900...I also had a go with the 23" this was over revving and 45knts.

If I were you I would be looking a 4 blader,the 150 engine gives me the impression that torque is plentifull with the boat catching up to the engine during acceleration so I'm now looking at 4 bladers.

Originally Posted by dwalters

Hi.

Firstly, I picked up my new Ribcraft 6.5 last week, which as expected has been fantastically built by the guys at Ribcraft. Many thanks to all them for producing such a good boat.

Following the run in at the weekend, I got the opportunity to give it full chat for a few minutes. The boat has a Suzuki DF175 on it which has a max rev range of 5,500 to 6,100 rpm.

On the run my boat max'd out at 4,800 rpm and 38 knots (SOG). Whilst I am not usually concerned about top speed, I do beleive this is considerably less than what the engine is capable of. Does anyone have any comments about whether this is just a prop change or something else (I am afraid I forgot to look at what pitch I was running).

Thanks

[parm]

nice boat Dwalters

[Hightower]

Just a thought.

Do you think the engine software is limiting revs during a run-in period?

[dwalters]

Originally Posted by Hightower

Just a thought.

Do you think the engine software is limiting revs during a run-in period?

I had wondered that, the engine has probably done 4 hours now. The Suzuki has the going home mode which limits to 3k rpm, so it would have the ability to limit during the run in time.

[TNDB]

Originally Posted by dwalters

I had wondered that, the engine has probably done 4 hours now. The Suzuki has the going home mode which limits to 3k rpm, so it would have the ability to limit during the run in time.

My DF150 ran 6000rpm during the sea trial at ~1 hour.

I'm a bit confused how Ribcraft let you have a package which clearly doesn't perform as it should. Is it normal practice to wait until the engine is broken in to conduct maximum speed tests or is my 1 hour brief trip to the max (done by the installer) more typical ?

I am not being delibrately contentious/critical (of Ribcarft) since it seems now my engine is run in it also needs a different prop so my sea trial max was far from definative