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[bobk]

Hidden Catch
Any ideas on how I can create a very small hidden catch for a removable deck panel.
The battery access panel is 12 cm long and 6 cm wide, fitted flush into a flanged rebate, and held at the front edge in a slot in the superstructure.  I am trying to avoid visible screws etc.  ie:  Method:  Angle front edge into slot, push rear of panel down until it ‘clicks’ into place. Needs to hold panel against flange.  Raised deck structure on panel can be used as ‘handle’ to lift open.
Suggestions most welcome please.

[rsm]

I would suggest small, strong magnets. You can pick up the neodymium ones quite cheaply on ebay.

[wibplus]

What I have on my Zwarte Zee is a pair of lugs (from scrap wood) which are glued to the panel and which hook under the decking at the front of the panel. At the rear there is a small magnet and plate glued to the underside of the panel to hold it in place.   

[mikearace]

Have you thought of magentic tape?  you will only need a small piece of each polarity on the end unsecured bit which can be put into a rebated slot to keep both the flange and the bit going onto it flush?  That should secure it adequately especially if the front part is going into a rebated slot

[bobk]

Thanks everyone.  Small neodymium magnets, that's lateral thinking.  Good idea !   
I was racking my brains along the lines of sprung plungers or a steering linkage ball with a stainless spring latch.
Bob K

[Colin Bishop]

Just be careful how you use magnets though. Some of them are pretty powerful and so you pull really hard and all of a sudden the bond breaks and the hatch comes up with a jerk and you find you've damaged your fittings/superstructure!

Colin

[john s 2]

Another way is a rubber band fastened of course underneath to tension the hatch down.Personally magnets sound ideal.John.

[riggers24]

I have a couple of magnetic catches holding the superstructure on one of my boats and never had any problems

[bobk]

Good point Colin. I will try a test piece first, and if necessary use an ABS shim.  I have ordered some 6 dia x 3 mm thick magnets on EBay.  When they arrive I can mock up something to gauge the separating force, and if too high try various thicknesses of shim between until it 'feels' right to seperate whilst still holding the panel down effectively.
John:  I had considered using elastic but keep getting it hooked up and unhooked might be too fiddly on a thrice weekly basis ? ie:  Mid week charging, then connecting and later disconnecting the battery on sailing days.  The magnets idea sounds so simple.
Thank you all    I will report on my HMS Amazon build blog.

[pugwash]

Sorry I haven't replied before - been trying to find this website - the magnets are very cheap and are round or oblong
various other useful bits on this site.


Geoff



http://hobby.uk.com/components/magnets-springs.html

[bobk]

Thanks for the link Geoff, but I had just ordered a set on EBay.  Magnets, brilliant idea, sounds like it will do the job without anything externally visible.
Bob

[bobk]

Neodymium magnetic catches were suggested.  I ordered a pack of 6 dia x 3.  When they arrived a pair appeared almost strong enough to attach the boat to the ceiling, so after trying plastic shims I eventually used a small strip of steel cut flush into the hatch base and a single magnet in a ply strip.  This seems to hold the hatch down well without needing force to lift the hatch edge.
Thank you all.  Photo on my build blog.
http://www.modelboatmayhem.co.uk/forum/index.php?topic=32820.msg331921;topicseen#msg331921

[Jerry C]

I use the magnet idea a fair bit on my flush hatches, I also use the 6mm by 3mm ones, to overcome the issue of them breaking away from the adhesive I lasercut the 6mmdia  hole in a 3mm acrylic plate, because a laser loses a little bit of focus as it cuts deeper the sides are ever so slightly tapered in allowing the magnet to fit perfectly for the first 1.5mm then becomes tight as you press it flush, so when you turn the plate over and glue it under your hatch it cannot escape.
I dont know how you are situated for laser cutters where you are but it should only cost a few dollars to have a few done.

[bobk]

I am pleased with how the magnetic catches work.  I do not have access to laser cutters, so drilled the ply for a tight fit, pressed the magnet in using '2 ton epoxy' with an additional ABS 2 mm strip epoxy'd underneath.  That should hold it.  Nice and compact, with a good click into place feel when the hatch snaps shut.