how fast is your rib?

[diaster]

Originally Posted by Searider

150hp Optimax Pro XS on a 1999 Scorpion 6.5
About 42 knots on a good day, light and clean. 40 knots after a couple of weeks in the water.

which prop please?

[gileszmilpro]

Not allowed to say how fast, but comfortably more than 55, even when the sea is lumpy.

[jackreno]

33 mph with just me onboard

Bombard C4 with a 50 hp Tohatsu 4 stroke 15 pitch prop at 5800 rpm.

[mavrick211]

Originally Posted by ShinyShoe

Hull speed only applies to displacement speed. Never heard that depth of the V affects hill speed...

The calculation is:



1.34 x √LWL



LWL = waterline length in feet

Result is knots...



You'll find a number less than 10 for most RIBs... but most RIBs will have top speeds >20knots on the plane.

I’m just comparing it to a bass boat that has a flat bottom on the back same length and hp as mine but goes at least 20knots faster
If I get over 42mph it chine walks badly

[Searider]

Originally Posted by diaster

which prop please?

19" Lazer II

[jackreno]

Hull shape has a lot to do with it, I had a 11 foot Novurania with a 30 hp and did about the same top speed as my current Bombard with a 50 hp..

The Novurania had a deep hull while the Bombard is mostly flat hull, the tubes on the Bombard do not get out of the water and it causes drag but the Novurania at top speed was unstable and chine walked while the Bombard is steady at top speed.

So as to a long run the Bombard would over all be faster cause I can maintain top speed safely..

[Searider90]

44 mph 2pob Avon SR -5 , Yamaha 90 2stroke

[Miller]

44kts with a 19p prop and 42kts with a 21p.. that was going into a head wind with 3 on board and 140 quids worth of fuel ( about 5 gallons these days)

[Sprocker]

Ribeye S650, Yamaha 200, 2 people, 180litres fuel, 42kts past Salcombe last weekend.

[Ajsimp]

Ceasar p850 twin Honda 225’s 49.7kts gps. Full 500L tanks and 2 people on board. Going to run the tanks down so I can crack 50!

[tebay91]

Valiant DR490
Merc 60HP
33 Knts, 2 up

[Safi]

Sr6 mercury efi 225 laser2 prop 21p
57kts 5800rpm (on limiter) cinewalks baadly after about 47kts or earlier if trimmed up, the boat are steady up to 40kts after that all kinds of bounsing and cinewalking

[MChivers]

Wow, I’ll need to check mine as it’s a 2t yam 200 hpdi and maxes @ around 38mph! A bit slow compared to the above.

[Safi]

Originally Posted by MChivers

Wow, I’ll need to check mine as it’s a 2t yam 200 hpdi and maxes @ around 38mph! A bit slow compared to the above.

Do you mean you have a sr6 with a 200 hpdi yamaha and you only get about 33kts max speed?
If so you defenetly need to check it, as people get about 43kts with 150hp 4strokes

[beemer]

this thread is ridiculous,,,,

[beerbelly]

Originally Posted by beemer

this thread is ridiculous,,,,

how far can you piss up a wall

[Pikey Dave]

Originally Posted by beemer

this thread is ridiculous,,,,

270 odd replies, somebody likes it[emoji6]

[jwalker]

Originally Posted by beerbelly

how far can you piss up a wall

Not very far but me boat can do 100mph!

[Jojosrib]

Brig 610 with a f130 18p prop. 200 kg on board inc fuel.

39 knots WOT.

27 knots cruise, 4600 rpm, 20 LPH.

[MChivers]

A couple of weeks it was only reaching 35mph (200 hpdi on 7.5 Cobra), changed the plugs, emptied the hull which had loads of rain water in it, anti-fouled with hard race and reached 40mph yesterday. Better but I do think it should be hitting around 45-48 if anyone has any suggestions ?