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Old 16 April 2015, 11:55   #31
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And That's what I gonna do. Until I make a my mind about do I sell my engine and look for twins or buy another one like I have.
I'm not cutting my boat .that tought is history.
Have no problems making a bracket and I'm sure he will be ok to hold the engine. Few things needs to be engineered before: make something that I won't bend control cables when tilting. And find out underfloor petrol tank locations.
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Old 16 April 2015, 15:07   #32
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I call cobra ribs today...they never did any ribs for rnli.that question is answered.
And there was me thinking that the question HAD been answered

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I would say, not RNLI.
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The rig is commercial, but not ex-RNLI.
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Yes and it is definitely not ex RNLI
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this isn't an RNLI boat either.
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To be clear the RNLI boats were not Cobras.
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Old 16 April 2015, 15:46   #33
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And there was me thinking that the question HAD been answered
The fella just had to make sure.
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Old 16 April 2015, 16:25   #34
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Come on guys cut the guy some slack he's new & doesn't know the level of knowledge on here
It's all to easy to be negative about what people are trying to achieve
not everyone has deep pockets or years of experience
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Old 16 April 2015, 18:42   #35
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Abyss.

Theory is all well & good, but some of us have a budget and a hull.

Your current combo is probably not too dissimilar to a scaled up version of my first RIB- an SR4 with a 25 Hp on the transom. Read the forum here you'd think I'd have struggled to get out the marina! needless to say I had some amazing cruises with that boat.

Your hull is definitely set up for twins, and I would guess that two of your current engine would do nicely (check the maker's plate / book of words for actual HP ratings!)

Now, assuming you have that engine already or it's a nice easy / cheap buy, as I said before, the big issue might be finding a twin for it, BUT old engines appear all the time, and I would be reasonably confident you could find it a twin at a sensible price.

Now, above there are many posts about "buy a new <whatever>, but I will throw this into the mix: I bought my 1973 vintage 60Hp clamshell for 200 with no guarantees (and the fallout from that decision is contained in many an old post on here!). A used modern 4-stroke 60Hp would have set me back the best part of 8K. Now, I agree the modern engines are probably slightly more fuel efficient (definitely quieter!), but how long will it take me to burn enough fuel to equal a 7800 purchase saving? (OK, it's more of a 6000 saving by the time I fully rebuilt it, but the point still stands!)

Me? I would Google / Ebay / whatever you local boat auction is for that style / HP of engine (remembering it's a rebadged Merc) and see what a twin would cost you. My gut feel is that would be a long term easier way to go based on sawing transoms about & the "lardy diver kitting up" comment above...

Also do a search for twin single - if you want backup a "big aux" isn't such a bad thing!
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Old 16 April 2015, 19:57   #36
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Someone really likes to say:- I told you so ok . I say it : all of you were right . I was wrong !
If that's good enough I want to move on to second part.
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Old 16 April 2015, 21:02   #37
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which is:
i understand that engine i have is old, inefficient ,loud and stinky...but, even if i will find some twins for sale (in my price range) they will be very close to the era where this mariner is from. so that said -is it better ,easier look for twins or look for another 135 mercury/mariner?
in fact ,non of the things (loud stinky etc..) bothers me .cause:all i need the rib for- is diving.
and that how it works: i load everything and go about 30 min. MAX to the dive site.stop .dive once,then once more and go back .another 30 min. multiply that about 20 times per season...
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Old 16 April 2015, 21:13   #38
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[QUOTE=9D280;674266]Abyss.

Theory is all well & good, but some of us have a budget and a hull.


Now, assuming you have that engine already or it's a nice easy / cheap buy, as I said before, the big issue might be finding a twin for it, BUT old engines appear all the time, and I would be reasonably confident you could find it a twin at a sensible price.

Now, above there are many posts about "buy a new <whatever>, but I will throw this into the mix: I bought my 1973 vintage 60Hp clamshell for 200 with no guarantees (and the fallout from that decision is contained in many an old post on here!). A used modern 4-stroke 60Hp would have set me back the best part of 8K. Now, I agree the modern engines are probably slightly more fuel efficient (definitely quieter!), but how long will it take me to burn enough fuel to equal a 7800 purchase saving? (OK, it's more of a 6000 saving by the time I fully rebuilt it, but the point still stands!)

Me? I would Google / Ebay / whatever you local boat auction is for that style / HP of engine (remembering it's a rebadged Merc) and see what a twin would cost you. My gut feel is that would be a long term easier way to go based on sawing transoms about & the "lardy diver kitting up" comment above...

exactly my point... and thats what came up like someone said after 30 sec of google...

Mariner 135Hp Outboard | eBay

price is bit high sided, but they come up frequently
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Old 16 April 2015, 21:59   #39
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If you can get a second 135 Merc/mariner the same, go for it. With 2x135hp, you've got a manageable boat which at a guess will burn less fuel than with the single 135 -ie, it'll have an actual planing cruise speed rather than flat out and falling off the plane with a load on.

FWIW though, if you're going to do it, do it 1st or you're going to have to buy new cables for the motors and re-rig them.That's a serious pain in the butt. Push-pull cables aren't easy to do away with excess lengths, specially if you've got under deck trunking.
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Old 17 April 2015, 03:02   #40
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Few questions.Rib project

I feel your pain, boating on a budget is a real struggle, especially when you have the size of hull you have.

IMHO?, a pair of those 130's are going to be shockingly pricey to run/maintain. I ran a pair of 60s on a 5.8m hull and fully loaded i was using anything up to 1.4 litres a mile. I couldn't stomach it.

I bought a four stroke and notched the transom to accept the single. Many people frown upon it, as long as its done properly I don't fully understand why. I've saved 40kgs on my transom so in theory it should sit a little higher in the water and the cut out takes the transom height to a normal long shaft transom anyway.

I've gone from 2 older/thirsty/pricey/inefficient 2 strokes to a modern/economical/lighter/more reliable 4 stroke. It's a win win situation in my eyes.

I don't have pocketfuls of cash I can chuck at a boat and couldn't be doing with the hassle of buying and selling. You can only piss with the cock you've got.

Basically what I'm trying to say is.....I'd cut the transom and go with a bigger single because I don't have the pockets but that's just me.
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