Mounting Flap Boards

Steve Sanford

Steve Sanford

Well-known member
Good morning, All~


Over the years, I have made several sets of flap boards for South Bay Duckboats. Making the boards is straightforward. More challenging is mounting them to the vessel. The original flap boards on South Bays were mounted via hinges to 2x4 blocks bolted through the deck. I have replaced most of the mounting blocks that have come my way, making them larger and more soundly fastened. I also like to make them so that the boards will lay level when down - so decoys can be set on them when setting out or picking up the rig.


I have probably posted at least parts of my process previously - but I just came across this folder of images - and got an inquiry from Luke Krucher here on duckboats.


The first thing is to measure the bevel of the mounting surface. The blocks themselves will be plumb - so a level across the coamings on a boat that is level on saw horses - gives a good reading with a bevel gauge.




View attachment 1 Block bevel.jpg



I use stock at least 2 inches thick - either Mahogany or Locust (shown here). Each block is shaped and marked (port or stbd, fwd or aft) and drilled BEFORE sawing the bevel.


The bevel is cut on the table saw. The "cut-offs" - the bottom halves - are used as the backer blocks for the through-bolts. This allows the washers and nuts to make up square to the backers.


View attachment 2 New Blocks.jpg



I usually seal the block with epoxy - followed by duckboat paint. Here is a set for a different vessel. Although sealed and painted, these have not yet been drilled or beveled.



View attachment Flap Boards 03 blocks.JPG



I use galvanized (hot-dipped) hinges with brass pins - or solid brass. Two quarter-inch carriage bolts pass through the each, its block and its backer - and are fastened from below with a fender washer and nut.



View attachment sm 8 Hinges and cbolts.jpg



It is important that the blocks be aligned fore and aft so the hinges do not bind. A straight edge is clamped to the blocks so the bolt holes can be located properly.


View attachment 7 Aligning blocks.JPG



Everything gets thoroughly bedded in 3M 5200 during installation. The 5200 should be wiped thoroughly after fastening so it will not need to be removed after curing.



View attachment sm 9 Mounted and sealed.jpg



Here is another alternative - using the original mounting blocks - which were treated 2x4 stock. These blocks have been reinstalled - bedded in 5200 - with 1/2-inch plywood backers below decks.


I added the third block to support the flap board level. The cleat is handy for lashing the boat sideways against the bog - using bog spikes.


BTW: These flap boards are about 12 inches tall - as is the new spray shield - which is also wider than the original. The flap boards are fastened to the hinges with brass FH machine screws - with acorn nuts on the inner/upper side of the boards.





View attachment sm FB 31 installed.JPG



Hope this helps!


SJS



 
Steve,

I'd love to see those boards in the down position. It seems like that leveling block on the gunnel is perfect. One of the ongoing issues that seems to present itself with flapper board setups is the spray off the bow/sides of the boat ending up on the flappers. I'm looking to modify my rig with something similar this season.
 
Good morning, Jay~


I will dig out some photos. Just got a new laptop - so older photos are elsewhere now.


Stay tuned,


SJS

 
Jay K said:
Steve,
This is an old photo notice one board up and one almost down
I'd love to see those boards in the down position. It seems like that leveling block on the gunnel is perfect. One of the ongoing issues that seems to present itself with flapper board setups is the spray off the bow/sides of the boat ending up on the flappers. I'm looking to modify my rig with something similar this season.
Click to expand...


View attachment 4-21-16 013.JPG
 
Good morning, Jay~


I had posted such a photo last month here:


http://www.duckboats.net/cgi-bin/forum/gforum.cgi?post=339356;do=post_view;forum_view=forum_view_collapsed;page=unread#unread


View attachment Port 28 - stern quarter flap down.JPG



I'm not sure I understand the issue you're trying to resolve. Keeping spray off the inside of the boards when under way? On some South Bays, I have added a way to hold the flapboards up (closed) - with eye straps and bungees. Combined with the larger spray shield, it keeps most of the Bay out of the cockpit when running in a chop.


All the best,


SJS























 
Thanks Steve, and Bill, for the photos. My Duck Invader flappers lie somewhat low when they are down. I am looking for a way just to avoid having the grass on them get wet while underway. It will take some tinkering on my part this offseason. What you have shown here gives me some idea how I might accomplish that.
 
Jay~


hmmm.....I think a Duck Invader is arriving here this weekend - needing flapboards among other things. It'll be a new challenge for me.


Stay tuned.


SJS

 
Steve,

Please, in all seriousness, please, post some progress pictures of that. I would love to see your thoughts and ideas put into action for that boat. It's a great rig. You really have a talent for designing concealment boards.
 
Good morning, Jay~


The vessel Invaded yesterday. However, the owner's plans do not involve flap boards. I will post as I proceed.



Once I begin working on it - in a week or so - I will think about flap boards and such. How do you plan to hunt your boat? One or two gunners? If so, sitting side-by-side - on floor or upon on seats, etc?


All the best,


SJS

 
Steve,
thanks for the help. I will be sure to post the rehab of my boat once warmer weather arrives. This boat never had flap boards and I am looking forward to finally being able to conceal my 100lb swamp collie.
 
Steve,

I hunt the boat parallel to the bank even when I am hunting solo. We/I use Momarsh Loungers and sit on the floor.

Rich is now offering the 2.0 version of his flappers on the DI13. The original ones were shorter. The taller ones conceal the hunters better but sit a little off the side of the boat leaving them wet when running. I have the taller 2.0 versions. I am also in talks with a local canvas maker to adapt the boat to a dodger when solo hunting.
 
Steve,

Small world. I reached out to the seller of that vessel and inquired who made the dodger when it was listed for sale. Rich did in-fact make that for him. It's a very neat concept. What are the other plans for the rig?

I, unfortunately, don't have too many in-action photos of the rig. I do have this one that somewhat shows how the flappers look in the up position.
View attachment IMG_4817.jpg
 
Whoa Whoa Steve ! Macy's never told Gimbels what they do !!!!!!!!!!! LOL
 
Last edited:
Steve,

Have you ever considered using friction hinges to mount flap boards? You wouldn't have the removable pin option, but they could be set at literally any angle and aren't difficult to move. Gemlux makes very high quality ones.
 
David~


Friction Hinges are new to this old brain....


https://gemlux.com/products/2976?variant=36700687204506&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=CjwKCAiA2fmdBhBpEiwA4CcHzWl5wbxQLa-uxGYUl6fjKVRjKI5ueX8jef8kYO5ucpjvEIeJC5qi4RoCmAgQAvD_BwE


I'm guessing an Allen wrench is used to adjust the tension/resistance:


View attachment Friction Hinge - Gemlux CROPPED.webp

I could see where they would be nice for holding flap boards up at any angle, but I believed most gunners want the boards to drop out of the way via gravity when they commence to open up on incoming fowl. Most rigs I see - including one on a Bauer (Guck) Boat yesterday use chocks which fall away or hang on the coamings when the flap boards are opened for shooting.


(This photo is the South Bay I restored in October.)



Portrait 6 - gun rest and chock.JPG



BTW: The Gemlux site looks interesting. I need to explore it further.


In any event, I will store this newfound knowledge away for future applications.



All the best!


SJS

 
Steve,

Gemlux makes very high quality products. I have a lot of their hardware on my fishing boat.

As for the friction hinges, they come preset. I tried to adjust the tension on my first set prior to mounting them and thought I had gone crazy. They come nearly impossible to move by hand however, once you mount them, the hatch door or flap board in this case can be moved easily yet, stays in place. They are great to keep hatches from falling on your head!
 
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