Addding cuddy to 5.2m RIB

yallis · 30 December 2011, 04:57

Hi
I wanted some advice on adding a cuddy to an existing 5.2m GRP/hypalon RIB.

It has been retubed and I am considering adding a small forward cabin for the sake of freeing up space and providing some protection from the elements. Will be built out of aluminium frame and 2 or 3mm plate.

My concerns are the redistribution of weight and changing the COG. I do also plan on setting the outboard further back with a jacking plate or pod 8-10" to help counter the change in COG and to free up some space in the stern. I dont think wind drag will be an issue because of the height of the cabin.
This project i feel is ideal for a larger vessel but for storage reasons i have to stick with this size.

Ive attached a scaled rough sketch (which has scanned badly) to illustrate. Will try to attach some better sketches.

Interested in opinions?

captnjack · 30 December 2011, 05:12

How much power is pushing this RIB? Hopefully as much as it will take as I think you'll find the increased windage significant.

willk · 30 December 2011, 09:46

Quote:

Originally Posted by yallis

This project i feel is ideal for a larger vessel but for storage reasons i have to stick with this size.

I think you know what the problem is. Frankly, I think there's just too much weight forward and too high a COG. That, and the Helm would take a severe pounding as it's bumpiest at the pointy end...

I'm a big fan of cabins, btw. Have a look at some here.

spartacus · 30 December 2011, 10:41

Nice example of 6.5m Redbay with console and canvas wrap-round.

More details here: Redbay 650 Wrapround Cabin - FAFB

gtflash · 30 December 2011, 10:44

cant you buy an old dory or flyer with a cabin and make a cut and shut.... have sleeping room then

boilermaker1 · 30 December 2011, 16:41

Took this photo in local marina today.. if you look close you will notice a 6.5m Humber with full cabin fitted. I have seen it motoring on calm days and it looks good..no idea what it behaves like in the rough

boilermaker1 · 30 December 2011, 17:14

Here is a better photo of Humer with cabin

wavelength · 30 December 2011, 17:19

Humber used to do a cuddy which was grp and sat on the tubes. Front end had a lip that slid under a fitting glued to tube and then the rest sat on velcro all round. Also held down by 4 ratchet straps. We used one with Falklands Conservation and it did keep the cold wind off, although the effect of a cuddy moving with the tubes as opposed to with the hull itself was kinda strange. The 5m boat had been re-engined with a new 50 soozi and it got along ok even with a few folk onboard. Pics somewhere when I get off this boat I'm on at the minute.

yallis · 31 December 2011, 04:18

My plan was to bolt the aluminium cuddy to the GRP and build around the tubes with no plan of the cuddy sitting on the tubes as such.

I wonder how these taxis ride as pictured.
I was using their cockpit area as a template for what i was trying to achieve. But i wonder if having the helm so far forward would signifcantly reduce ride comfort in the rough. These taxis do get out in the rough bay chop but granted theyre 7-8m vessels which probably offsets it somewhat.

Day Dream's · 01 January 2012, 18:29

Quote:

Originally Posted by boilermaker1

Took this photo in local marina today.. if you look close you will notice a 6.5m Humber with full cabin fitted. I have seen it motoring on calm days and it looks good..no idea what it behaves like in the rough

I know that boats owner, I believe he had to build a frame to off set the outboard to account for the extra weight of the cabin, he made the cabin himself.

willk · 01 January 2012, 18:38

Yes guys, but the OP has a 5.2m RIB. That's a lot less boat than 6.5m - I don't see how a cuddy is workable at this size.

HUMBER P4VWL · 01 January 2012, 20:13

I'd guess a bow cover like the deluxe sr would be better. Tarpaulin based like the D class I believe.

Maximus · 02 January 2012, 18:57

Surely you'd be better off putting your time, money and effort into getting a bigger RIB first,if you're serious about some kind of Cuddy?
Cant see how it could ever be practicle on that size RIB...Good luck all the same!

Neil Harvey · 02 January 2012, 19:07

I am also not convinced, but IIRC it has been done to an SR5.4, and another similar sized boat, but a longer cabin top than implied here, with the steering position more mid ships

Nathan k · 03 January 2012, 00:42

This looks intresting Everything about my Avon Searider RIB: Setting out to build a Pilothouse for my Avon Searider 5.4
finished boat at the bottom of the page http://searider54.blogspot.com/2008/...with-ribs.html

yallis · 03 January 2012, 03:02

Yeah I think all your advice is in line with what i was thinking.
Ill just have to wait until a get a bit more storage space.
But I will pursue building a decent framed canvas cover for the bow as pictured. With some tubular aluminium ribbing it can add some decent cover and it entirely removable which adds versatility. Keep the cockpit and add a bimini over the cockpit which again is removable and foldable when not required. I think that gives the best compromise.

Anyone have any experience with these canvas covers. My only worry is what would result from a green wave coming over the bow and landing on the canvas cover? Suppose you need good quality canvas and some decent framing...

bedajim · 03 January 2012, 03:39

That looks more like a tent, so maybe for use when moored only
I'm sure there was a member who had canvas sides that came up around the sides of the console to offer protection . I think it may of been on a shearwater but 100%
Jim

Try searching DIY spray deck

captnjack · 03 January 2012, 05:09

Quote:

Originally Posted by yallis

Yeah I think all your advice is in line with what i was thinking.
Ill just have to wait until a get a bit more storage space.
But I will pursue building a decent framed canvas cover for the bow as pictured. With some tubular aluminium ribbing it can add some decent cover and it entirely removable which adds versatility. Keep the cockpit and add a bimini over the cockpit which again is removable and foldable when not required. I think that gives the best compromise.

Anyone have any experience with these canvas covers. My only worry is what would result from a green wave coming over the bow and landing on the canvas cover? Suppose you need good quality canvas and some decent framing...

Seawater weighs about 64lbs a cubic foot. (I don't know how you'd think about this in liters, 100L waves = 102kg?)

No matter how you measure, any serious volume over the bow is quite possibly going to blow the seams apart on that cover, regardless of the framing behind it.

What are you trying to accomplish?
dry storage?
wave deflection?
sun shade?
wind break?

HUMBER P4VWL · 03 January 2012, 17:46

The ones above are popular in Greece as a sun shade. They'll be too weak for a "stuff" and may be a bit flappy at speed. Though I've seen you tube footage of them whilst on the plane.

Shearwater boat had canvas from the console. Looked good and more robust for miserable weather.