Yamaha 150 - what speed?

johnboym3 · 12 May 2009, 22:22

Hey guys just bought a RIB with a 4 stroke 150 yamaha outboard on it... i was expecting to get around 50mph at sea with it but i am getting around 34 mph flat

what do you reckon?

Nos4r2 · 12 May 2009, 22:25

Quote:

Originally Posted by johnboym3

Hey guys just bought a RIB with a 4 stroke 150 yamaha outboard on it... i was expecting to get around 50mph at sea with it but i am getting around 34 mph flat

what do you reckon?

What revs is it making, how much green stuff is growing on the bottom and is the hull full of water?

neilda · 12 May 2009, 22:26

Others are more qualified than I (actually everyone is at the moment), but a 150, depending on the size of RIB, should be in the 45+ area I would have thought. At least that's what the sales people say!

What RIB and size is it?

Heart-trouble · 12 May 2009, 22:47

is it trimmed right?

Trevor G · 12 May 2009, 22:48

Hi Neilda. I've a 2004 Yamaha F150AET on the back of my Ballistic 6.5 and I get a top speed of about 39 knots (Satnav speed) - this is 4-up with a pretty full tank but I'm not sure it will go much faster!
Trevor

johnboym3 · 12 May 2009, 22:48

Quote:

Originally Posted by Nos4r2

What revs is it making, how much green stuff is growing on the bottom and is the hull full of water?

it is revving to 4400rpm. dont think there is much on the bottom as it has been anti fouled.

no water in the hull

johnboym3 · 12 May 2009, 22:49

Quote:

Originally Posted by neilda

Others are more qualified than I (actually everyone is at the moment), but a 150, depending on the size of RIB, should be in the 45+ area I would have thought. At least that's what the sales people say!

What RIB and size is it?

its a ribeye 650 sport and it 6.5 meters

yeah i have moved the trim to all areas

Heart-trouble · 12 May 2009, 22:53

if yr on your own you should easily get 45-50mph @ 5600rpm, i think you have the wrong size prop

codprawn · 12 May 2009, 22:58

Have you experimented with the trim?

If so then it is the wrong prop or a damaged one - the hub could even be slipping.

It doesn't take much slime or other growth to rob you of a lot of speed either.

Nos4r2 · 12 May 2009, 23:13

Quote:

Originally Posted by johnboym3

it is revving to 4400rpm. dont think there is much on the bottom as it has been anti fouled.

no water in the hull

Your prop hub isn't slipping if you're only making 4400 rpm.

Physically check for slime buildup. You'd be surprised how much difference a small layer makes. More importantly find out what pitch and diameter propeller you've got. You should be doing between 5000 and 6000 rpm at wide open throttle depending on how much load is onboard so either
a) You're overpropped
b)Your hull is filthy (or worse but unlikely , damaged somewhere out of sight)
c)You've got an engine problem.

johnboym3 · 12 May 2009, 23:15

thanks guys, i will check all tomorrow

neilda · 12 May 2009, 23:28

Quote:

Originally Posted by DizzyLizzy

Hi Neilda. I've a 2004 Yamaha F150AET on the back of my Ballistic 6.5 and I get a top speed of about 39 knots (Satnav speed) - this is 4-up with a pretty full tank but I'm not sure it will go much faster!
Trevor

I've been reading the ads too much! The Ribeye 650 (with the Yamaha F150AETL) is regularly quoted as being able to do 50+ knots. However, I'm sure you're right that the actual real-world speed is somewhat lower.

codprawn · 12 May 2009, 23:29

Quote:

Originally Posted by Nos4r2

Your prop hub isn't slipping if you're only making 4400 rpm.

Physically check for slime buildup. You'd be surprised how much difference a small layer makes. More importantly find out what pitch and diameter propeller you've got. You should be doing between 5000 and 6000 rpm at wide open throttle depending on how much load is onboard so either
a) You're overpropped
b)Your hull is filthy (or worse but unlikely , damaged somewhere out of sight)
c)You've got an engine problem.

Whoops teach me to read all the text properly!!!

Hightower · 13 May 2009, 00:11

All of the above for problem solving. Plus one thing no one has mentioned. Are the throttle plates fully opening when the throttle lever is fully pushed forwards? It's easy to check!

I doubt that you will get more than about 40/42 knotts out of that package with a lightly loaded boat. Once you in the recommended WOT range it's More important to look at revs at verses cruising speed during set-up/prop selection.

allegria · 13 May 2009, 09:06

I've seen 43knots out of my Zodiac Medline II with the Yam 150, which i believe is a heavier boat. That was close to pulling maximum rev's and probably half to fully laden at the time.

neilda · 13 May 2009, 09:11

Just out of curiosity - what would a Yamaha 100 deliver in terms of cruising/top speed on a 6m RIB?

ryza00 · 13 May 2009, 10:20

With the Yam 150 on our Avon 580 we get 50mph at about 5800rpm

Bern Hanreck · 13 May 2009, 12:08

Neilda.......I cruise comfortably at 25 Knts and have a top speed of about 34 Knts under normal ( quite heavily loaded conditions ) . I do believe that if I don't fuel up and ditch the passengers I can find another 5knts.....

bedajim · 13 May 2009, 12:43

this may help

http://rib.net/forum/showthread.php?...&highlight=200