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Hatch question


Dnjost

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I am in the process of making the two hatches for my CS17.  The plans show a 1/8" spacer of some sort on the hatch framing inside edge. I cannot figure out the overall dimensions and purpose of this part of the build.  Is it to make up for the hatch lid being forward 1/8" off the outside edge?  The actual size of the cut out opening is not readily apparent, but am sure it will become self-evident once the parts are assembled.  Will cut the opening after the parts are assembled.  

 

Any insight would be helpful.  Thanks

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David-

My take is the 1/8" is clearance, not a structure itself. I think the deck beams and aft deck plans drive the dimensions. In other words, build your deck beam structure per plans. Next put on deck ( whether permanent or temporary), and trim the deck ply around the deck beams of the hatch covers.

Next put the hatch coamings around the hatch deck beam structure. Next, the hatch frames are attached to the deck itself, with a 1/8" clearance around the coamings. So while you have some dimensions for the deck beams, you are building the frame structure and then the top around what you have established on top side of deck.

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David-

My take is the 1/8" is clearance, not a structure itself. I think the deck beams and aft deck plans drive the dimensions. In other words, build your deck beam structure per plans. Next put on deck ( whether permanent or temporary), and trim the deck ply around the deck beams of the hatch covers.

Next put the hatch coamings around the hatch deck beam structure. Next, the hatch frames are attached to the deck itself, with a 1/8" clearance around the coamings. So while you have some dimensions for the deck beams, you are building the frame structure and then the top around what you have established on top side of deck.

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I should have been more specific.  It is on the page for the seat hatches in the cockpit.  on the bottom, inside, it indicates a 1/8" spacer.  This is shown in two views.  Would put up a photo from the plans, but would not want to infringe on Graham's copyright.  I can't tell if this is sandwiched between 1/4" material, or not.  Can't figure out it's purpose. 

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David,

 

You are correct, the 1/8" is a spacer. When the hatch is closed, the hatch front is flush with the seat front. As they are the same material (1/4" ply), the back side of the hatch front would bind with the coaming if it was hard against the inside of the seat front. There will be epoxy and paint to further aid in binding, not to mention minor building imperfections. Leave a 1/8" gap and all will be well.

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I think I have it!  Here are two hatch frames temporarily assembled with hot melt glue.  I now see why the spacer is necessary, as when the frame is installed, it causes the front panel to tilt away from the cockpit seat sides.  The spacer fills the gap created.  The channels will need to also be grouted to the sides of the cockpit as they will have a gap as well.  Unless I have done something terribly wrong, this is how I see things working.  Somebody stop me if I have it wrong.  

 

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I see that your hatch ring is upside down!! The hardwood outer ralis and the inner wall pieces parellel to them need to be flipped over so that the front edge (the face that is in plane with the cockpit side) is 90 degrees to the top surface. I will post some pictures in a few hours.

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Jim and Alan,  thanks so much for the visuals.  I definitely have these parts on upside down.  However, will need to check the dimensions again on these as when they are reversed they are all longer than the hatch base to which they are attached.  Did anyone else get this result?  I am pretty sure I read the dimensions on the plans correctly.  (12" on the long side off the right angled corner)  Nothing a couple of minutes with the saw and sander can't fix. 

 

 

 

My seat tops are also in place already, I was just going to cut out the hole for the hatch frames and attach it with screws while the glue dries.  

 

Jim, did you find the hatches on the forward compartment handy?  I was reluctant to add these to this part as right now I am considering these to be flotation compartments which are sealed with screw in deck plates for inspection purposes. 

 

David  

 

Afterwards!  

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David-

I did the exact same thing except I had glued my with epoxy before noticing. Good move on the temporary glue.It is a wierd thing to visualize. I think you will find after you cut out out the seat holes you will need to cut out some extra of the 1x2 seat cleats ( maybe incorrect terminology) to fit in the seat hatch frames but it is doable with a multi master/ Drexel tool. You may find that clamps ft in there fine and you may not need too many screws.

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They are designed as flotation and I do not suggest that any deviate from Grahams design. I do find the extra storage very useful. In the aft hatches I keep lines to starboard and safety equipment and rain gear to port. In the forward  compartments I keep bottled water and snacks and a place for guest to throw small gear.  I use my lazzerette to stow cushions and life jackets and misc bulky but light items. In the forepeak I keep two anchors and rodes (in milk crates) as well as fenders. In the cockpit lockers I have small plastic baskets to keep stuff from getting lost. 

 

Jim

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David, that's more like it! I do see what your saying about the sides being longer than the base frame. I don't know about the dimensions exactly but the front edge of the hardwood sides and the piece across the front should be in the same plane. If anything I leave a slight gap between the cockpit side and the front piece (the bottom piece in your first picture) so that the front of the lid does not hit it when the lid is closed and the lid is allowed to be flush with the cockpit sides and seat tops.

Also the top edges of the inner parts should be slightly (3/32") below the plane of the hardwood sides top edge if you want to leave a gap for a neoprene or foam rubber gasket on the underside of the lid.

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  • 1 month later...

This post and the video have been a great help.  My replacement hatch for Belhaven #3 is nearly complete and I'm contemplating the hinge installation. I intend to drill oversized holes, fill them with epoxy, and re-drill as seems to be standard.  Are wood screws adequate or should I through bolt with machine screws?   Seems to me the wood screws would be more waterproof but not as strong.  What have other's done and has anyone had any failures that might be educational.

Thanks

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