how fast is your rib?

[bkils@mac.com]

Duncan,

I pulled the prop off and this is what it reads on the inside:
10 3/8 x 13 G. The engine is a 2009 50HP 2 stroke.

Bjoern

[Jonny H]

I'm sorry but that's not possible what are you using to record your speed ?

[bkils@mac.com]

@Jonny since you asked: Raymarine A50 GPS and secondary iphone iNavX software. With my old 40HP 2 stroke she topped out at 42 knots WOT with a 38x1.3 P prop. Next time you're in manhattan shoot me an email - you're welcome aboard.

[willk]

Bjoern

I can see this debate becoming a Did/Didn't kinda argument.

48 knots on a SR4 with a Yammie 50 is Guinness Book of Records material - the upper end reported for this rig (on here) is below 40kts, mid 30's being typical. There's not much SR4 left in the water at 35kts. I guess that explains some of the replies you've got/are going to get.

Like Guinness, an independent witness or a video is going to be needed to convince readers that this is the real deal.

Then, you'll be a kind of Searider God on here

[Searider]

kph?

knots per hour?

[bkils@mac.com]

yup 48 knots (Kts) as in 55.2 Mph = 88.9 Km/h = 24.7 m/s. It's an old searider 4m bought in germany in 1986.

[bkils@mac.com]

I'll shoot you guys video the next time I'm out - most likely this Wednesday. You're right about not much hull being in the water --I've uploaded 2 pictures to the 'RIB PHOTOS' tab.

[thomas]

I maybe new to small boats but approaching 35kts in my 4.5m was starting to get a bit hairy, approaching 50 in a 4m would require balls of steel - looking forward to vid.

[Leapy]

[Oscarguitar]

48 km/ph maybe? 30 mph give or take.

Max theoretical speed using 5500 rpm, 1.85 ratio, 13 in pitch is 37 mph. This would be with no prop slip. SR 4 re-writes the laws of physics. Prop would need to be a 21 at least.

Looking forward to the video......

[Courageous]

88.9km/hr apparently

[Xk59D]

5.6 avon adventure, 100hp 4 stroke- 40 knots on GPS.

achieved on a nice small chop and 2 up.

cheers

[Oscarguitar]

I had the exact same set up. Lovely combination, don't think I ever had it going that fast though but I expect my sons did! Nice one.

[Poly]

Originally Posted by bkils@mac.com

yup 48 knots (Kts) as in 55.2 Mph = 88.9 Km/h = 24.7 m/s.

You see that is why our two countries have a "special relationship"...

... because FIBnet exists on both sides of the pond

Its just about possible to get to 38 knots with that prop on the right engine:

13" rotating at 6500* / 1.8** rpm (x 60 min/hr) = 2816666 "/hr = 38.6 Nautical miles / hr.

* the maximum RPM for any 2-stroke I've ever seen.
** the minimum gearbox ratio of any outboard I've ever seen.

Even then a 10% prop slip is considered normal, and less than about 8% amazing (or unbelievable depending on your outlook!).

If you really are getting 48 knots the engine must be screaming its tits off (over 8000 rpm) in which case a video of it blowing up would be good.

[Oscarguitar]

I calculated 37 mph using the max RPM of 5500 from the yamaha site and the 1.86 ratio for the lower unit. I agree about the video!

Test was Wednesday so we should get the pictures today! Cant wait!

[Courageous]

Originally Posted by Polwart

If you really are getting 48 knots the engine must be screaming its tits off (over 8000 rpm) in which case a video of it blowing up would be good.

[bkils@mac.com]

For my friends on the other side of the pond, the mathmagicians and those by now out of popcorn: I took her on the Hudson River yesterday but there was some wind and chop and I wasn't able to duplicate the exact number I got on flat water. Anyways here's the raw video clip: Hudson River, New York on Vimeo
Enjoy the holidays :-) Over and Out.

[Xk59D]

Originally Posted by Oscarguitar

I had the exact same set up. Lovely combination, don't think I ever had it going that fast though but I expect my sons did!Attachment 64189 Nice one.

my own one i've only seen the magic number twice of 40knots on the gps.

it is more normal to see 35/36 knots from it as i'm usually out with 3/4 people.

cheers

[Courageous]

Fair fecks Bjoern I saw 44.5kts on that there screen sir!

[Searider]

Originally Posted by bkils@mac.com

For my friends on the other side of the pond, the mathmagicians and those by now out of popcorn: I took her on the Hudson River yesterday but there was some wind and chop and I wasn't able to duplicate the exact number I got on flat water. Anyways here's the raw video clip: Hudson River, New York on Vimeo
Enjoy the holidays :-) Over and Out.

That looks impressive - was that 44 point something?

Is your boat a Rescue spec / deluxe / or an early boat?
Engine a new Yam 50hp 2 stroke? We can't get those here unfortunately. What RPM were you making.?
Standard Al prop or SS?

Was there any current and did you run the other way as well?

I'd love a 48 knot searider. :-)