Another dim plywood question

Greenheart

Greenheart

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If, for unspecified purposes, I thought I needed a 3" cube of teak, could I do just as well by cutting a smallish piece of top-grade 18mm marine ply into four x 75mm squares, then screw/glue the pieces into a cube?

I like the idea that the criss-crossed laminates will add strength in an application that's going to need it, but which won't be large enough for sheer size to give it great strength.

The exact size of the cubes wouldn't be important.

And, what's the best glue, available in very small quantities, for ply?
 
Perfectly feasible - although the thought police will get you for mixing up Imperial and Metric measurements in the same structure!, Suggest Polyurethane adhesive such as Pur or Gorilla for small jobs like this. One part out of a squeezy bottle. Don't clamp too tight as you may get glue starvation. Wear gloves as it stains delicate hands and takes ages to wear off (the hands that is).
 
Trouble is Dan is not going to end up with a 3" cube, but 2.95*2.95*2.83 (plus the thickness of 3 glue lines in the latter plane).

Can't have him being that sloppy with a precision built boat like an Osprey.
 
davidej said:
How would pieces of ply, when glued together, transmute themselves into teaK?
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:o ;)

I started thinking teak, as something tough and workable, though possibly its toughness defies its workability. Ply will do nicely.

Thanks Tranona, I'll give it a try. To prevent 'glue-starvation', how should I be sure of the best pressure on a 75mm square? I'd have imagined something like a 2 litre cider bottle would apply plenty - but maybe too much? I can drink it down to the right weight, whatever you think that might be?

I'll happily confound metric/imperial warriors on both sides. I can generally convert instantly, if necessary...I rarely think of boat-lengths in meters, I never think of sail areas in square meters and yet I never EVER think of volumes in imperial...in respect of weights and volume, the metric system is a fabulous easy gift of comprehension, where imperial is a license to confuse and over-complicate. Or should that be licence? :rolleyes:

(Runs for cover...)
 
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why use wood at all? Why not plastic e.g. a kitchen chopping board - it won't rot and it wont need varnishing.

However, I do accept that a nicely varnished piece of wood will look better!
 
It's true, tough plastic would be fine too, and most likely I'll paint it, in whatever shade I eventually decide is better than that green...

...so kitchen chopping board might be a smart answer.

Apologies for being mysterious...I was (and I remain) embarrassed by the simple daftness that I'm trying to resolve...

...as very close followers of my strangely slothful sailing story will already know, I impulsively bought rowlock-supports which would fit well upon a 90º coaming...but the Osprey's edges aren't 90º...they aren't any degrees, they're a smooth quarter-circle. So, it's the old round-deck, square-rollock-support problem...

View attachment 30761

...which requires me to build up a 90º edge in the neighbourhood where the oar will rest.

My thinking was to make these ruddy wooden cubes, and using a jigsaw, take a deep shark's finn-shaped section out of each, so that the finished 'cubes' could mount on either side of the hull, bolted to grip the deck securely (with butterfly nuts on the underside?) through the solid side-decks' overhangs, and would be removable for the long periods that they're not needed, leaving only the bolt-holes, which could be filled discreetly by shorter bolts, with domed heads.

My hope was not to permanently disfigure the decks, if possible.

Please don't say 'For god's sake just go sailing!!'...this rowlocking business isn't a reason why I haven't yet launched, it's just something I'd like to do. :D

If anyone has a practical alternative solution, I'll be glad to hear it.
 
Yes plastic rowlocks and their plastic brackets are just rollocks - fit only for childrens boats! - get yourself some proper manly ones!


In my wayfarer cruising days I had some constructed out of stainless steel - basically a flat plate with 4 screw holes and rowlock sized hole together with a two inch tube welded over the rowlock hole. The tube is then slotted into a hole on the side deck. Make sure you position it in the right place and that it is a strong point or that you can re-inforce it coz there is considerable force when you are rowing.
 
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prv said:
Why not just get the kind of rowlock that mounts on a flat side-deck..?
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D'you mean the ones which require a substantial recess dug into the deck, perhaps 22mm dia, which is lined with metal to take the rowlock? Plus securing screws...

...I couldn't find those for sale...plus I was thinking I could avoid that much damage to the deck, and also make them disappear most of the time, with my bolt-ons.

I s'pose strength ought to be the deciding factor - I'm quite an energetic rower so any wobbliness in construction will be tested to destruction in a very short time.

I thought the black plastic ones I've bought looked pretty rugged...but maybe they'll end up as sculling-oar supports. Where can I find the metal recessed variety?
 
dancrane said:
D'you mean the ones which require a substantial recess dug into the deck, perhaps 22mm dia, which is lined with metal to take the rowlock? Plus securing screws...
Click to expand...

Dunno about "dug into". I was thinking of something like alteredoutlook's design above. I was assuming plastic, as that's what you tend to see on chandlery shelves, but certainly stainless would be better. Should just need a central hole for the tube that holds the leg of the rowlock, and a screw hole either side.

Don't know how thick your side decks are, but certainly worth considering reinforcement if they're thin. Either a few more layers of glass and resin, or ply epoxied in place (both under the side deck, not on top of it, assuming you have access).

dancrane said:
Where can I find the metal recessed variety?
Click to expand...

No idea, I have a 30-horse Volvo for this kind of thing :D

Pete
 
prv said:
...I was thinking of something like alteredoutlook's design above.
Click to expand...

Sounds good, but they must be manufactured by somebody somewhere. I doubt it's a design anyone hasn't seen - they're everywhere, aren't they? Except for sale. :(

The Osprey's sidedeck-overhangs seem very solidly constructed; at least 1.5" of dense material - presumably thick GRP on lighter stiffening. I reckon it'll stand up to an oar pulling hard, but I'm less sure about the structural integrity of the rowlock-support, or the thing I attach it to, to fix it on that curving deck-edge!

Here's a terrible photo of a Youtube vid about an Osprey on a lake in Canada, being rowed...

View attachment 30768

...regrettably, it's not clear how the rowlocks are attached...but he definitely hasn't set the rowlock through the fabric of the deck.
 
.why use wood at all? Why not plastic e.g. a kitchen chopping board - it won't rot and it wont need varnishing.
 ................because, unless they are the right thickness to begin with, as plastic chopping boards are made of polyethylene (virtually impossible to bond even with plasma treatment ) or polypropylene ( dificult to bond as far as DIY is concerned)
 
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