MI12 nester?

[glossieblack]

Still looking for a genuine rowboat that can be cut in half and nested. Is it feasible to build MI12 as a nester, with the forward half not having an athwartships frame but beefeed up fibreglass seams instead?

[peter-curacao]

Does this help ? http://forums.bateau2.com/viewtopic.php?f=25&t=40580

[glossieblack]

Thanks Peter, the connector setup of the nesting F5 is most helpful. What I'm struggling with at the moment when trying to figure out how to build a MI12 or a 90% OT16 as a nester is how to modify framing arrangements to make the nesting possible. For example MI12 has three athwartships frames - one fairly close to the bow, one amidships and one fairly close to the stern. Now if want to you cut the boat in half to be able to nest one half inside the other, the amidships frame needs to be built as two separating 'transoms' for the two halves, and you need to do away with one athwartships frame in one half.

Jacques, I'm wondering how to achieve sufficient strength in the approximately 6' long half without an intermediate athwartships frame. I'm wondering if either i) laminated ply and glass encapsulated fore-aft stringers (similar in profile to the external sheer rub rails) installed internally along each of the 4 chine joints, and/or ii) additional laminations of fiberglass tape internally and externally along the 4 chine joints would do the job the deleted athwartships frame? If so, MI12 could nest snugly?

[AMC]

Why not look at the ROW13. It would look to be a better candidate. It has one central mid frame, that could be doubled to split the halves apart, and the back 'deck' looks like it could be easily modified to accommodate the bow when nested.

EDIT: why?
If you look at the FB11 as a paradigm for a nesting boat, two things come to the forefront. 1, the break in the boat comes slightly OVER half way toward the bow, leaving you a 'nesting' section that is shorter the 'nest' section, this is important, and the MI12 would seem to need to be split almost dead center. Second, the FB11 break occurs after the boat has started to narrow toward the bow, leaving you a narrower piece to nest. With the MI12, you are going to end up trying to nest two equal pieces, a difficult proposition at best. It looks as if both these accommodations could be made to the ROW13.

[glossieblack]

Thanks AMC, it looks as though Row 13 could nest ok, as could OT16, for the reasons you've outlined. I favour OT16 because while primarily a row boat, it offers a 2hp outboard option. After investigating a nesting MI 12 further, I realise it won't work because the top planks are almost vertical amidships - meaning that compact vertical nesting is not possible. So a nesting OT16 is my best hope. However the slightly longer aft 'half' can't have an internal athwartships frame if reasonably compact nesting is to be achieved, so I'm hoping Jacques can recommend compensating additional fibreglass laminations on the chine seams as required.

[AMC]

That would certainly be a BIG nester. The ROW13 offers the same 2hp option, and wouldn't require you scaling down the plans. Is this boat for use as a tender or just a compact boat for general use?

[glossieblack]

The primary purpose is as a nesting recreational rower to be stored on the foredeck of my cruising sailboat. I have an inflatable tender with a rigid glass composite V-bottom and a 2hp outboard hanging off davits on yacht’s transom for use as a general tender. However when I cruise in tropical Australian waters where crocodiles abound, I'd like to be able to use the nesting rower as a hard dink.

On deck assembly of a 13-14 foot nester will not be practical, so easy on-water assembly is important. To minimise the chances of taking on water in a chop during assembly, I'd prefer that the two 'transoms' of the two floating parts be full height. This means that it is not possible to have the primary rowing thwart straddling the join line – the thwart needs to be aft of the join line.

Edit: As importantly, each of the two parts need to have no internally protruding structural frames, i.e. each part needs to be a structurally rigid external shell/monocoque, to facilitate i) compact nesting and ii) minimum interference with the yacht’s foredeck hatches when the nester is stored upside down on the foredeck.

I have just enough fore-aft foredeck space to handle either a nesting R13 or an OT16 reduced 10% all over - to become an OT14.

Edit: If there are to be no internal protruding structural frames in each part, could scantlings be modified by i) increasing the size of the structural rub rail, and/or ii) increasing the chine seam fibreglass laminations, and/or iii) running extra fibreglass laminations athwartships, inside and outside the hull, where internal frames would have otherwise have been?

Jacques, I’m hoping you can do a CAD review on the nesting pros and cons of R13 and OT14, and advise on modifed scantlings for the better one. I'd like to start building!

[jacquesmm]

1. We have plans for a nester:
http://www.bateau.com/proddetail.php?prod=FB11
The pictures are not good but the boat is proven and works well.

2. You guessed correctly that the frames are the problem for a long nesting hull To nest an OT16 would require a complete redesign and I can't put that on the design list now, sorry.