Newbie in need of help

teamplonker · 13 July 2012, 20:21

Hi All
I have just bought a 3.2 metre rib from a rib retube company in devon, It does not have a manufacturers plate on it so i have no idea of max persons and max out board size it will take.
Is there a rule of thumb for working this out or is best guess.
thanks in advance
Lee

Poly · 13 July 2012, 20:25

(1) The rib retube company can probably ID it and then you can check with the maker.
(2) Their is an ISO standard for HP on ribs, i'll see if I can find it for you. [EDIT take a look here: http://www.rib.net/forum/f36/engine-...ml#post145062]
(3) Have a look at similar sized boats - but compare transom designs as not all are the same.

teamplonker · 13 July 2012, 21:08

Thanks for the quick response.
The retube company does not know the maker, I have followed the formula in the link and it comes back Max 15hp but i have looked at other ribs of simalar Length and width with 25-35hp outboards on.
I don't want to waste money on an under powered motor on the other hand I don't want to rip the transom out.
Im still unsure for max persons though.
Lee

PeterM · 13 July 2012, 21:21

Post some pics of it. Someone will know what it is :-)

Poly · 13 July 2012, 22:07

Quote:

Originally Posted by teamplonker

Thanks for the quick response.
The retube company does not know the maker, I have followed the formula in the link and it comes back Max 15hp but i have looked at other ribs of simalar Length and width with 25-35hp outboards on.
I don't want to waste money on an under powered motor on the other hand I don't want to rip the transom out.
Im still unsure for max persons though.
Lee

Are you sure you've worked it out right?

- most RIBs are specced on the distance from front of bow to transom, but the formula demands bow to tip of sponsons behind transom. Presumably that is at least 3.2m.
- i'd have guess the beam was 1.6m ish.
- that would give you 'near as damn it' a 25HP limit.

teamplonker · 14 July 2012, 06:48

Thanks again for your quick responses.
I will remeasure with the formula ( bow to tip of sponsons behind transom), is this the front of bow? also is the width measured from the outside of the tubes at the widest point?.
I will get some pics posted this weekend, Maybe someone will know what it is .
Lee

Dhf · 14 July 2012, 09:45

[QUOTE=teamplonker;475542]
I will remeasure with the formula ( bow to tip of sponsons behind transom), is this the front of bow?
No, the transom is at the stern (rear end) where the engine clamps on,
the transom would be the extent with most hard boats, but with ribs the tubes /sponsons travel further back past the transom, for extra stability.

"also is the width measured from the outside of the tubes at the widest point?."
Yes, usually getting wider toward the back / stern,

I will get some pics posted this weekend, Maybe someone will know what it is .
That's a great idea, I'll bet someone on here will know it,
All the best,

paul tilley · 14 July 2012, 16:53

Bet no one knows what it is

teamplonker · 14 July 2012, 19:19

You seem so sure, Paul From Dartmouth " Mmm that rings a bell " the rib i've bought is in Dartmouth with a man called Paul

Poly · 14 July 2012, 20:00

Quote:

Originally Posted by teamplonker

Thanks again for your quick responses.
I will remeasure with the formula ( bow to tip of sponsons behind transom), is this the front of bow? also is the width measured from the outside of the tubes at the widest point?.
I will get some pics posted this weekend, Maybe someone will know what it is .
Lee

Yes the absolute widest and longest measurements (effectively the size of box you would need to put it in). There are certainly ribs around that have bigger engines than the ISO standard suggests, but they should have been tested with that size of engine.