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Old 29 May 2015, 16:57   #1
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Our Ideal rib....thoughts?

We we're thinking of buying/ assembling a new rib. We have narrowed it down to a Humber 6.0m or 6.3m with either a115 single on the back or two 60's. If one 60 went down would the other 60 on its own be able to get the rib to plane? The weight of two 60's is the same approx as one 115. We were keen on twin 60's.Any thoughts? What top speed could we expect. We're more interested in cruising. What speed is it likely to cruise ? Many thanks Nik
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Old 29 May 2015, 18:30   #2
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Destroyer or ocean pro?

You can probably get a lightly loaded 6m to plane with 60hp BUT the prop you would choose would be very different from if it was half of a pair. You might still be able to find a chromite that works.

If you go twins make sure the electrics and fuel systems are independent otherwise you don't really get redundancy.
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Old 29 May 2015, 19:14   #3
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Hi. What have you crossed off to arrive at your final choice? A 6/6.3m rig with 115 or 2x60hp is not gonna be too lively.

Don't dismiss 1x main and a decent sized aux. Don't forget, twins are 2xs.
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Old 29 May 2015, 19:15   #4
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Go for an Ocean Pro, doesn't matter whether it is 6m or 6.3m.
There is not a lot of width on the transom to squeeze in two OBs and I don't believe you need twin engine redundancy with the modern engine's reliability.
I would go for a single OB, I had a Suzuki DF140 (which in reality is circa 125 hp) and it gave me a top speed of 40 kts with an "all day" cruise speed of 30 kts.
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Old 29 May 2015, 22:54   #5
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Thanks all. What is the difference between the oceon pro and the destroyer? A top of 40 and an all day of 30 would do me fine. I find passengers get fed up going much faster than constant 30knts. No chat! I didn't appreciate the need for the wider transom for the twins. Will both these hulls take twins? If I had them propped so the twins ran max efficiency, and i presume a higher pitch, would that pitch be then to course to enable the boat to plane with one 60 without resorting to a finer prop? Ta Nik
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Old 30 May 2015, 03:16   #6
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Thanks all. What is the difference between the oceon pro and the destroyer?
Both are good hull's, but quite different. If you are still unsure of that then I think Mollers question is pertinent.
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Old 30 May 2015, 05:11   #7
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A top of 40 and an all day of 30 would do me fine.
You'll be well shy of these figures with the set-ups that you've proposed. You'll need to be at, or very near max design hp to achieve 40knots max and cruising of 30.

With the twins, you're going to huge extra cost for a potentially 'never' event. Unless you're planning to head miles offshore, a decent aux will get you to port easily if you should be unlucky. As Poly said, unless the twins are truly independent, the set-up will not be fail proof.
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Old 30 May 2015, 06:06   #8
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I had a used Ocean Pro 6.0, I then ordered a brand new Ocean Pro 6.3, assuming it to be just the same as the previous one with an extra foot length. When I picked it up, externally it was the same but internally the old one had a much lower floor, mounted one chine lower, and felt much more secure as the tubes were higher in relation to the console - The new 6.3 with the high floor always felt like you were sat ontop of the boat, not in it like the old one.
I had a new Yamaha 130hp and would do 40 from memory although I had an 80mph phantom at the same time so top speed was irrelevant!
It was too big really for my needs and I ended up selling it and buying a second hand attaque, with the low floor.

Although Humber make great hulls, particularly the Ocean pro upto 6.3, the finishing and fit out leaves a lot to be desired, they use the cheapest tat for fuel systems etc and items like A frames seldom fit and are bent into place etc. I've been fitting them out for nearly twenty years and have seen all their faults and they haven't really improved. The last one I did three years ago was delivered as a supposedly finished and sea trialled boat and I spent almost a week correcting their fitout with some truly shocking faults. When I bought my Ocean pro I ordered it as a bare hull and unsecured console only.
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Old 30 May 2015, 07:28   #9
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You'll be well shy of these figures with the set-ups that you've proposed. You'll need to be at, or very near max design hp to achieve 40knots max and cruising of 30.

With the twins, you're going to huge extra cost for a potentially 'never' event. Unless you're planning to head miles offshore, a decent aux will get you to port easily if you should be unlucky. As Poly said, unless the twins are truly independent, the set-up will not be fail proof.
Clearly all engines need appropriate servicing to ensure reliability however twins inherently will be a safer option. Lots of talk about separate fuel systems ( yet I bet both individual tanks would be filled from the same potentially contaminated fuel supply...............) and electrics, however obviously twins benefit from two of everything, including gear boxes, engines , props, timing belts ( where appropriate ) - components can, will and do fail! I've run both single and twin set-ups and even taking into account the extra costs I'd personally always choose twins. Not forgetting manoeuvring with twins is a joy
It would certainly pay the OP to try both styles.
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Old 30 May 2015, 07:56   #10
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however twins inherently will be a safer option..
I agree, but depending on the OP's intended usage, twins are a lot of added expensive in terms of purchase and running costs added to reduced efficiency, for only a degree of additional safety. An aux will get you home, just not as quickly.

At purchase time, it's his money to do with as he wishes.
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