Making hatches that fit.

[cheddar24manParticipant @cheddar24man]

What’s the best way to make sure your hatches actually fit, come off and go on easily?

I’ve cut the three “hatches” from the deck and my thought is to glue a protruding strip, about 5mm above the deck, around the inside of the deck hole and the outside of the removed hatch panel.

Will this work? It’ll be a tight fit me thinks.

[Chris FellowsParticipant @chrisfellows72943]

Better to use a new piece of panel as the best and easiest way is to glue the upstands in place and then build the hatch around them. Cover the upstands in cling film so that the hatch doesn’t get glued to them! Then fit the hatch downstands around the upstands and then glue the hatch panel to the top – cut slightly oversize and then sand to the downstands , job done. If the hatch is a bit tight sand the upstands carefully until you get a good fit.

Chris

 

[Richard SimpsonParticipant @richardsimpson88330]

My take on this, and, as usual there will be as many preferences are there are members, is to always make any removeable part in place on the model to guarantee a nice close fit.

The way I do it is to cut the hole and fit the coaming, as you have done.  Then build the sides of the hatch in place around the coamings, which could be either a softwood frame or vertical sidings, as you prefer.  Hold in place with blobs of BluTac while the glue sets so you have a frame that perfectly fits snugly around the coaming.  Then you can build up from there, again with everything still in place.  Finally glue the cover onto the sides while it remains on the model, with a slight overlap.  You can then remove it and trim it so the cover fits perfectly. and add stiffeners inside to beef everything up.

Some modellers try to use the removed piece of ply as the hatch cover but I never bother.  It will never be big enough to give you enough to play with for that perfect finish.

I build hatch covers this way and even wooden superstructure components in the same way to always give me a nice snug fit.

[Richard SimpsonParticipant @richardsimpson88330]

Must be a first, myself and Chris both do the same thing!

[Chris FellowsParticipant @chrisfellows72943]

Don’t forget our hand painting!

It’s usually me that whilst composing a posting gets beaten to it!

I’m just getting back into posting on here again before I start building again after my lengthy layoff!

Chris

[Richard SimpsonParticipant @richardsimpson88330]

Couple of pictures to help:

First fit the coaming

 

Then fit the hatch sides in place.  The polythene helps keep the glue off the deck.  Don’t get the glue on the coaming though!

 

Dress up the cover for a perfect finish.

 

 

Decorate as desired.

 

 

Exactly the same process to build a removeable superstructure unit.

 

 

[Chris Fellows]

On Chris Fellows Said:

Don’t forget our hand painting!

It’s usually me that whilst composing a posting gets beaten to it!

I’m just getting back into posting on here again before I start building again after my lengthy layoff!

Chris

Look forward to it Chris.

[cheddar24manParticipant @cheddar24man]

Fantastic guys, problem solved for this old man but one thing I’m still thinking about is that the deck is curved port to starboard, slopes both ways, so can’t put a solid piece of wood crossways, maybe lots a small pieces to allow the deck to bend? Front to back is OK as there is no bend.

[Richard SimpsonParticipant @richardsimpson88330]

I’m afraid there is no quick and easy solution, you have to think through what you have available and how you are going to achieve the required result with what you have.

Some how or another the lower edge of the transverse members have to be shaped to fit the camber of the deck.  One way I have achieved this was to tape a piece of abrasive to the deck adjacent to the coaming and rub the cross member over it to form a matching curve in the lower edge.  You may or may not have room to do this so the solution will have to be tailored to suit.  It might be a case of trial and error, starting with the cross members lower edges and shaping to suit until you achieve the best fit, then build the other bits around them.

This was using the method described above.

 

[cheddar24manParticipant @cheddar24man]

Thanks Richard, your pictures have answered my question. You have fitted the deck to the frame BEFORE making/attaching the hatches! I was trying to make them on my building board having cut out the hatch openings on the deck sheet.

I’m advised to install all the motor, steering gear before fitting the deck so will have to wait as not received yet!

I also presume the whole inside gets a thin coating of varnish to waterproof it.

I love this forum and the helpfulness of the members……………

 

[John W EParticipant @johnwe]

hi there

Is this a hatch for the MTB that you are building?   If so, it will need to be a flush fit deck hatch.   One way of doing this is to create a lip on the inside of the deck around the outside of the hatch opening.  The way I did my hatch on the bloodhound build was I cut out the exact overall shape of the deck so that it fitted the hull perfectly first.   Then, before gluing the deck to the hull I built an internal framework on the inside of the deck – I used 5mm square obechi.  When this had dried, I cut through the inside of the hatch, so it left the framework on the inside of the deck and the piece which came out, I framed that with 5mm obechi.

Then, when I had assembled all of the hull and everything, I made a flange to fit around the inside of the deck hatch.  This prevents the hatch from falling through.

As they say, pictures do speak a thousands words, so, here are a couple of pictures.

 

[Ray Wood 3Participant @raywood3]

Hi Ched,

I’m with John on the flush deck solution , I have built a couple of MTB’s and they run dry if you have good spray rails on the chines to deflect the water, upstands are better for a sailing boat as there needs to be a good seal, I use a cork gasket on my sailing barges hatches.

Regards Ray

[cheddar24manParticipant @cheddar24man]

Oh my goodness, now I need to remove the bits I’ve already put around the edges of the deck hatch openings and go the flush fit! No problem, just a bit more time🤓

[cheddar24manParticipant @cheddar24man]

I see one has to reinforce the deck underneath which makes sense as my deck is only 1.5mm thick!

Should one varnish the deck underside, and all the hull inside before fitting the deck??

[Richard SimpsonParticipant @richardsimpson88330]

Painting it with something to protect it just in case of water ingress is always a good idea.

[Colin BishopModerator @colinbishop34627]

As Richard says but try and avoid surfaces which need to be glued together as there is a better bond with the original material. Missing a few bits isn’t critical either way though. I coat the underside of my decks with Deluxe Materials EZe Kote but any wood sealer or even paint will do the job.

Colin

[Ray Wood 3Participant @raywood3]

Hi All,

Obviously me being a lazy bugger don’t bother to seal under the deck, out of sight is out of mind, If that gets wet the boat is in serious trouble 🙂

Regards Ray

[John W EParticipant @johnwe]

Hi there

If your plywood is of good quality, such as birch ply, obtained from a good model shop/reliable source, the chances are it will be classed as weather proof/water resistant.  Therefore, no real need to seal it on the inside.  The only thing that would concern is the plywood from which the kit is made from.   Going by what your photographs show; it is a form of laser cut ply, which does tend to be a rather cheaper lite ply which is not water proof – it would debond if wet – so, make sure that is well sealed.

John

[cheddar24manParticipant @cheddar24man]

Thanks guys, I think for safety I’ll give the inside one coat once I’ve finished the installation of motor mounts etc.

The deck is Birch so should be OK.

Cheers

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