Difference between and 50hp and 60hp on My Ranieri Revolution 4.55

[Bigplumbs]

On the new to us Ranieri Revolution 4.55 we have the typical Tohatsu 50 hp 2 stroke which performed OK. On my 4.5 m Rib I have a 60 hp Mariner 2 Stroke which I love. I recently had the opportunity to buy an identical 60 hp Mariner which needs a little work at what I thought was a good price. So I went ahead and bought it.

In theory a 60hp is 20% more power than a 50 hp and in my case the 60 is 25KG heavier at 100kg v 75kg and is well within the specs of the boat. So those with experience or indeed any others what difference do you think I would experience if I swapped the 50 Tohatsu out for the Mariner 60 hp.

First I have got to build a wooden stand to work on the 60 and also assemble the 2Ton engine hoist I bought to lift the thing about

Here is a video of the Ranieri 4.55 with the 50hp on as reference.

If I could get 4 knots more and the engine did not seem to be running fast at 23 knots in the cruise I would be happy

 

[limecc]

Strange nobody replied so here goes, this is how I imagine it. The boat will be transformed.

1000cc 60hp vs 700cc 50hp, you should have a lot more torque and low pickup which is what the stern heavy Revolution needs.

Different gearbox ratios mean a 14p on the Tohatsu is equivalent to 11.5p on the Mariner, that's nearly 29kn. The extra power should enable the new engine to pull a 13" pitch to 32kn, 26kn cruising at 4500rpm. A 14" prop would give you nearly 35kn but from experience I don't think 60hp is enough for that.

I found getting the engine height right is worth the effort whatever pitch you have or you will be disappointed. What are the markings on the current props?

I wonder if the Mariner has the standard ISO engine holes? You might have to re-drill the transom. I had to do this for the lower holes anyway to allow full range of adjustment, AV plate -20mm to +40mm

 

[Bigplumbs]

Strange nobody replied so here goes, this is how I imagine it. The boat will be transformed.

1000cc 60hp vs 700cc 50hp, you should have a lot more torque and low pickup which is what the stern heavy Revolution needs.

Different gearbox ratios mean a 14p on the Tohatsu is equivalent to 11.5p on the Mariner, that's nearly 29kn. The extra power should enable the new engine to pull a 13" pitch to 32kn, 26kn cruising at 4500rpm. A 14" prop would give you nearly 35kn but from experience I don't think 60hp is enough for that.

I found getting the engine height right is worth the effort whatever pitch you have or you will be disappointed. What are the markings on the current props?

I wonder if the Mariner has the standard ISO engine holes? You might have to re-drill the transom. I had to do this for the lower holes anyway to allow full range of adjustment, AV plate -20mm to +40mm

I am fairly sure the engine holes on the Mariner are the same as the Tohatso. I was happy with the Tohatsu but when this engine became available for £750 I decided to go with it. I wont mess around with props as I find all that far to anoying

 

[limecc]

I am fairly sure the engine holes on the Mariner are the same as the Tohatso. I was happy with the Tohatsu but when this engine became available for £750 I decided to go with it. I wont mess around with props as I find all that far to anoying

Which means neither will you experiment with engine height so setting the AV plate 20mm above keel will be a safe one-time thing. You might not needed to change props anyway as it will probably have a 13p already. Am interested if this is so.