Few questions.Rib project

abyss · 14 April 2015, 14:42

Hi ,
started a project and would like some answers and advice:
1) is this ex rnli boat?how to tell?is it a good rib?
2) what material is the tubes?
3) would this engine be powerful enough for divers boat? 5-6 divers plus gear?
4)engine shaft is 20 inch .rib transom is about 27 so i have to cut to fit it.is it ok to do that?or i better look for 25 inch engine shaft?
i know,i know too many for the first post,but season is nearly there so i have to be quick.
thanks in advance.
regards

Starovich · 14 April 2015, 15:46

more experience will be along shortly,
I would say, not RNLI (maybe used by in some capacity but not as a rescue boat).
I think Cobra are Hypalon I'm sure some one will poke me if i'm wrong
Cant see clearly the HP I would say min 150 hp needed.
Seven inch is a lot to cut out i would say look for an engine closer to the correct length.

9D280 · 14 April 2015, 16:58

Quote:

Originally Posted by abyss

Hi ,
started a project and would like some answers and advice:
1) is this ex rnli boat?how to tell?is it a good rib?
2) what material is the tubes?
3) would this engine be powerful enough for divers boat? 5-6 divers plus gear?
4)engine shaft is 20 inch .rib transom is about 27 so i have to cut to fit it.is it ok to do that?or i better look for 25 inch engine shaft?
i know,i know too many for the first post,but season is nearly there so i have to be quick.
thanks in advance.
regards

Hi! Welcome to the madhouse!

I'm at work at the mo, so can't enlarge the pics too much -hence 2 Qs - How big is the boat (I guess 6.5-ish m?) and how many Gee Gees is that engne? - I guess somewhrere round the 130 mark from the shape?

Re./ the transom height / engine leg length- I reckon that hull was set up for twins based on the fact the "lip" is missing in the locations I would expect you would want to park a pair of engines. Now, this is where the measurements get fun:

Measure the depth of the transom at the midpoint of those two cutouts - I'll bet the depth is 25 inches.

I'll need to hand you over to the tank carrying brigade (I don't dive!) but beofre you start sawing the transom around - and assuming that is a 6.5m or bigger hull & 130 odd HP engine, do you actually want to be looking for a twin for it? (Although they are not a young design so that may be a bit more difficult than it looks unless you don't mind resuscitating engines!)

And before the "twin vs single debate starts again - if the transom is set up for a pair, why @rse around with it & risk a leak / rotten transom? Especially as those Clamshell type engines were remarkably light for their HP.

abyss · 14 April 2015, 16:58

It's 135 hp mariner.

abyss · 14 April 2015, 17:11

It's a 7m long if measured with the tubes.135 hp 2 stroke.
Don't have to fly with it.just runaround with my fellow divers. Don't want to spend xxx amounts of $ too.so if it's safe to put something out of what I have and it will work I will do it.
Have no problems to fabricate most of the hardware for the project .
It's my first boating experience ...

Nos4r2 · 14 April 2015, 17:44

Welcome to Ribnet

Nice looking hull.

This may sound a little negative I'm afraid.

What you've got there is a hull and motor that really shouldn't go together. The hull is set up for twins, and realistically cutting the transom down may reveal/cause things you don't want happen.
135hp isn't really enough HP for that hull, and that old motor is going to use a LOT of fuel-more so as you'll be caning it to get it to go with 5-6 divers+gear and cox. I'd expect 50 litres per hour or more.

Essentially, either get a motor/motors that'll fit the hull you have (which would be desirable), with at least 175hp and newer tech, or get a hull that'll go with that motor (less desirable but cheaper inital outlay).

Pikey Dave · 14 April 2015, 18:09

Just to add to what's been said, there's no way would I cut a transom down on a dive boat. When you get loaded up, freeboard is everything. You get some lardy @rsed diver kitting up at the stern & it soon starts getting very wet.

.....sh1t happens.......

paintman · 14 April 2015, 18:56

Quote:

Originally Posted by Nos4r2

135hp isn't really enough HP for that hull, and that old motor is going to use a LOT of fuel-more so as you'll be caning it to get it to go with 5-6 divers+gear and cox.

Same as the Mercury on my hardboat - 17' Dory Sportsman. They are basically a detuned 150hp. V6 2 litre with 'oil injection' - although it's really just drip-fed into the fuel line before the carbs - which has a certain reputation. Disabling the oil pump & using a 50:1 premix is recommended on some sites & appears to be a common mod. Mine's standard, but I did have the oil feed pipe split, fortunately I was drifting & fishing at the time & had the 'Where's that oil slick at the back of the boat coming from?' moment which is preferable to the 'Oh dear it's seized' one

Not exactly slow, but they ARE thirsty! I do toy with changing it & if I lived nearer the sea & used it more I probably would.

Pikey Dave · 14 April 2015, 19:40

Quote:

Originally Posted by paintman

Not exactly slow, but they ARE thirsty!.

+1 My mate had one on a 585 RC & it was a thirsty, stinking beast

Maximus · 14 April 2015, 20:10

Quote:

Originally Posted by Pikey Dave

+1 My mate had one on a 585 RC & it was a thirsty, stinking beast

Aren't ALL Yorkshiremen!?

paintman · 14 April 2015, 20:22

Quote:

Originally Posted by Pikey Dave

+1 My mate had one on a 585 RC & it was a thirsty, stinking beast

Ah, forgot that bit. There is a very brief smoke screen issue when started after sitting overnight

According to the workshop manual it weighs in at 172kg

abyss · 14 April 2015, 21:29

By the look of it my transom is very solid. Thick too -3 inches.
But...it seems everyone is against of cutting it .Ok then, how about laser cut, inch thick ,steel plate to mount engine lower then transom top and use existing holes of the two outboards to secure it?
I'm gonna look for twin setup for sale but up to then this mariner has to be ok.
About the hull... Never saw before that leisure craft would have that kind of A frame with capsize recovery device and radar reflector...also the gel coat color,twin underfloor petrol tanks...
Anyone with more knowledge about RNLI boats?

Mollers · 14 April 2015, 21:42

Quote:

Originally Posted by abyss

About the hull... Never saw before that leisure craft would have that kind of A frame with capsize recovery device and radar reflector...also the gel coat color,twin underfloor petrol tanks...
Anyone with more knowledge about RNLI boats?

The rig is commercial, but not ex-RNLI.
If you're gonna doubt the information that you're given from fellas clearly far more knowledgeable than yourself, you'll not get very far on this forum, or possibly any other.

Starovich · 14 April 2015, 21:45

I see your hoping its x rnli, but i very much doubt it. Maybe ask the manufactrers

abyss · 14 April 2015, 22:15

Had no intension to offend anyone by having my doubts , but the often answers like :I don't think so or in my opinion - are wrong.
If someone would answer : no, not RNLI because this and that etc... Then I wouldn't question that any more
I not hoping that's ex rnli. Way should I ?it is what it is and if it floats that's good enough for me. Definitive answer would help me search for the answers of the other questions that I might have . Cause believe it or not I'm never saw another picture of the boat on the web that looks like mine.

Starovich · 14 April 2015, 22:17

30 sec on google

paintman · 14 April 2015, 22:20

You will need to speak to the manufacturers - details are above - with your hull details to see who the hull was supplied to.
The RNLI do much of their own building & you could also try asking them:Inshore Lifeboat Centre
Hopefully you will get a definitive answer from one or the other.

abyss · 14 April 2015, 22:32

30 sec on google show that what I have seen for months.
No of them look one to one like mine.
I gonna contact both cobra and rnli tomorrow .have two numbers on the hull .

Ribochet · 14 April 2015, 22:34

Quote:

Originally Posted by abyss

Anyone with more knowledge about RNLI boats?

Yes and it is definitely not ex RNLI

Quote:

Originally Posted by Mollers

The rig is commercial, but not ex-RNLI.
If you're gonna doubt the information that you're given from fellas clearly far more knowledgeable than yourself, you'll not get very far on this forum, or possibly any other.

+ 1

willk · 14 April 2015, 22:36

Quote:

Originally Posted by abyss

Had no intension to offend anyone by having my doubts , but the often answers like :I don't think so or in my opinion - are wrong.
If someone would answer : no, not RNLI because this and that etc... Then I wouldn't question that any more
I not hoping that's ex rnli. Way should I ?it is what it is and if it floats that's good enough for me. Definitive answer would help me search for the answers of the other questions that I might have . Cause believe it or not I'm never saw another picture of the boat on the web that looks like mine.

Evenin' Abyss,

I see that you've met Mollers. He's our resident Training Troll. If you get over him, you're in...

FYI - the RNLI question is a regular one. Lots of random orange RIBs are sold as "ex-RNLI". It means nothing and IMO, this isn't an RNLI boat either. They just don't do boats like that. What it almost certainly IS will be a commercial or government department boat - Fisheries or similar would be my choice - maybe an Independent Lifeboat. Picton Cobra have been making RIBs since the late 80's and your's is an old 'un. That said, it has huge potential and I'd suggest that you listen to the advice here and don't butcher it for the sake of hitting the water sooner rather than later.

IMHO, it's designed for twins and will be MUCH easier to keep that way. Sell that engine you have - unless you build/buy a proper offset transom jack, it's only ever going to be a balls, just sayin'...

My advice is stick on a few more detailed photos and have a chat about what could be done with it. There are a few rodney's on here, but there is also a mine of information and experience that you'll not find easily elsewhere.

ATB

willk (Honorary Oop Northerner)