Advice req - Outboard size

ausaviator · 02 May 2020, 08:20

Hi all,

Long time reader, first time poster.

I've purchased a low-cost RIB from OS.

It 5 metres and weighs almost 300kg's. It's brand new.

The manufacturer usually plate it at 40-60hp which seems a little low to me. They said I can put anything on it up to 120 and they will change the plate as it's crazily low for Euro certification, to be ultra-safe.

We have a 5.5 metre Zodiac in the family and I'd class it as under-powered with an Evinrude Etec 90, so I'm feeling like this can handle a 75 Mercury 4-stroke.

The issue is that the 60hp is 112kg's and the 75hp is 163 kg's. They are both 4 cylinders but the 75hp is a 2.1 litre capacity engine, whereas the 60hp is a 1 litre, thus the same as a 40hp.

So the 60 hp is a pimped up 40hp and the 75hp is a low-end 90 and about the same size.

Decisions... decisions...

The kids are young <8 and will be looking at skiing and towing in the near future. It's not about cost, as both are affordable. Just weight.

Thinking more about it, walking from front to back of the boat on an average RIB at 80kg's myself, you'd hardly notice it, so 51 kg's would hardly matter.

Thoughts? Speed would be nice to be honest...

What HP would other similar units have on them?

Ribtecer · 02 May 2020, 08:55

I have a 5.3 which had a 60 on it when I bought it. I had the same boat with a 60 on it before and is was ok but a bit sluggish when loaded.

Then I had another of the same boat with a 75, this time I have gone for a 90. It is now ready to try but we're on lockdown, so I can't confirm it's performance but I reckon it's going to be terrific with 90 horse power.

120 sounds too much to me, and then there's the weight to consider.

Good luck with it and keep us posted.

Sandman · 02 May 2020, 09:34

Let us know more about the rib you have bought. I have seen a few Chinese ribs advertised for not a lot of money but have no experience of them. Would love to know about the quality of them (I’m not in the market for one, just curious).

Ferryman · 03 May 2020, 11:26

Change the plate??? What make is it?

Ferryman · 03 May 2020, 11:28

Also 120hp on a 5m rib is way over the top for general use - who is the manufacturer??

Orwell boy · 03 May 2020, 20:22

I have done a very similar repower to what your suggesting with my ribcraft 5.3 , when i purchased it had 114kg yam 60 four stroke injection ,32 knots ,one up ,twin dive console so quite light build ,now maxed recommended with honda 2014 100 vtec with blast technology weighing 165kg ,early days for me as honda was on heavier boat so propped all wrong on my 1 and only trip out ,holeshot was awesome but only 15 pitch prop but still 32 knots but rev limiter was in very early athough we were two up , have a couple of 17 and 19 pitch props to try but then lockdown !!
previously had highfield 5 metre with 90 hp vtec and that was quick but not silly

dgpw · 06 May 2020, 21:06

90 hp :-)

ausaviator · 28 May 2020, 13:24

Well I pressed the go button a couple of months ago and purchased a RIB from China.

It's the 5.0 metre version of the RIB below which is 5.2 metres, however it measures at 5.1 metres, due to the pencil ends which I chose.

They have a 4.8, a new 5.0 model and a 5.2 model, all with different glass hull lengths.

You can customise your colours, components and accessories. I got an extra couple of ladders for the kids, extra handles on the hulls, cover, anchor, sun shade, extra switches, movable console and a few other bits and pieces. Am fitting a Garmin fish/sonar unit and fixed VHF. It's got a 60 litre fuel tank.

I've purchased a 60HP 4-stroke mercury with SS prop and vessel view 403 display.

I had to go the 60hp rather than the 75 because they said that the 75 would be too heavy. I came close to getting a 70hp Yamaha, however I was advised not to as the engine can be a disappointment as it appears to be a small capacity high revving engine that's the same as the 60 but has a higher maximum RPM.

Shipping time from China to Australia is around 20 days. I'll advise further when it arrives.

I've since found a company in the Netherlands selling these exact same ribs. For what cost me AUD$9k delivered, they are offering for AUD$28k for the same RIB! (with no engine)