replacement for my stolen rib

crui05 · 15 August 2018, 19:14

have seen a humber 6.3 with a 115 hp engine. 6k. previosly a rescue boat.
i hae the chance to replace my stolen beaver 2 (see previous messgae)
i wondered if the engine is underpowered for a boat this size
any info is much appreciated.
james.

Poly · 15 August 2018, 19:19

Depends what you plan to use it for, and which Humber it is, but most people on here would be unimpressed with that combo.

crui05 · 15 August 2018, 19:22

just for me. crusing the east and south coast. nosing around the next corner
why is it not a good combo

willk · 15 August 2018, 19:27

Quote:

Originally Posted by crui05

i wondered if the engine is underpowered for a boat this size.

Quote:

Originally Posted by Poly

... but most people on here would be unimpressed with that combo.

Quote:

Originally Posted by crui05

why is it not a good combo

HUMBER P4VWL · 15 August 2018, 20:04

I’d imagine it’d get up on the plane and cruise around with just you. If you had 3 passengers it’d really struggle to get up on the plane, if it did it’d take a long time.

We have a 2.5L V6 2S Merc on a 6.3 Humber. The 115 is a 1.7L 4cyl 2S. It just won’t push the boat about v quickly, or get going v well.

IMHO it’s underpowered, but take it for a spin and see for yourself!!

Poly · 15 August 2018, 22:16

Quote:

Originally Posted by HUMBER P4VWL

I’d imagine it’d get up on the plane and cruise around with just you. If you had 3 passengers it’d really struggle to get up on the plane, if it did it’d take a long time.

You are probably being unnecessarily pessimistic. Humber website suggests the 6.3 is probably the narrow beam OP. As a rescue boat it will at times have had to carry a reasonable load and probably tow a handful of dinghies. It will be (should be) propped accordingly. So it won’t be blisteringly fast, and if you are used to acceleration that knocks you into the back of your seat you may well be frustrated but it should plane even with four average adults on board. I’d guess top speed moderately loaded would be mid to high 20’s. Only the OP will know how that suits him. Whilst some of it is purely down to “the need for speed” it is fair to say if you are going out in conditions where one person needs a 6.3m boat then at times you will be pushing the throttle and waiting whilst you climb the wave; that’s not a great feeling and also means you are working the engine hard burning more fuel. Should you find yourself calf deep in water in big waves the elephant trunks seem to take a long time when the engine is screening away.

If it were me doing what you described I’d save my money for a slightly smaller boat.

Xk59D · 15 August 2018, 23:00

It depends what 115 it is, if it is a mercury/mariner/yamaha 4 stroke for example then I would give it a wide berth on a 6.3.

I had the same engine on a 5.6 and it would REALLY struggle to plane 4 up, was fine once up there.

If it was an optimax or similar then a 115 would be ok but will never set the world alight.

phantom 19 · 15 August 2018, 23:10

A 115hp on an ocean pro 6.3 is absolutely fine and not underpowered at all, I remember rigging quite a few of them with the Yamaha f115 when it first came out 20 years ago, all would do mid/high 30s knots no problem. One was a commercial dive boat which would carry 8 divers plus kit with no issues. If a 5.6 struggled to get on the plane with 4 up it was setup wrongly!

The 6.3 was I thought the best Ocean pro (especially if it was the rare low floor version with the floor positioned one chine lower then normal) it was the largest size they did in that mould, moving up to the 6.5 was a completely different mould and had less deck space than the 6.3.

HUMBER P4VWL · 16 August 2018, 23:36

Just go test it! ...and let us know.

crui05 · 17 August 2018, 07:50

testing on sunday.

HUMBER P4VWL · 17 August 2018, 09:08

I’d recommend taking a couple of crew so you can see any change in performance. It’s incredible the difference a bit of weight makes! See how much fuel is on board too.

In our Humber 6.3, it jumps up on to the plane in only a few seconds when alone. Add 3 x 15stone blokes and 140L of fuel and it’s like driving a truck compared to a hot hatch back, pushing the boat over the hump of water takes quite some time. You may find a 115 4S takes forever and you have to shift weight about. As others said, if a 2S, it may be ok.

crui05 · 17 August 2018, 12:02

thanks for that. i will be watching it.
i will probably only rarely be carrying anyone else. but yea, fuel can be heavy.
james.