South Bay Floor Boards

Luke Krucher

New member
Hi all, looking for information on the original floor boards that came installed in a south bay duck boat. Did they come attached to the floor nailed or screwed to the cross hull stringers/supports? I just got this one that has been kept covered and has not been used for a very long time. The floorboards are said to be original but they are nailed into cross members with what looks to be ringed drywall nails possible marine nails.
My only concern is water intrusion, which there is no sign of currently.



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Hi Dave, let me do a bit of digging tomorrow and get back to you. Its a pretty simple grass boat that unfortunately has seen better days.
 
Luke,
Being that the SBDB predates my birth, I can't say officially what the original builders of the boats did to affix the floorboards, but I do know that many years ago, nearly every one I saw was screwed into the ribs. I know that as owners noticed the rot that was associated with each hole, they took it upon themselves to avoid doing this which gave birth to a variety of alternative methods. The least technical being what was done to my boat which was making floorboards in two pieces, then putting down cross pieces to then screw the floorboards to. The cross pieces would "ride" on the ribs. But the boards were cut in such a configuration that even though they were floating, there was no where up, back, left or right for them to go. I know that Steve has implemented a system of turn buttons to more snuggly affix the boards to their location on the floor, as opposed to letting them chatter and vibrate and move slightly. Is that boat new to you?
 
I know that on Brian's boat, an early model with no foam flotation, each of the plywood floor ribs were rotted. and it was obvious screws or nails penetrated at regular spacing. He ground all of them out, and replaced all the rotted plywood and replaced it with plastic and glassed over. The plywood offered no strength, it was simply a form to make the glass beam that added some stiffness I believe. Brian added a few more and also longitudinal stiffeners and made it quite robust with little added weight.
 
Luke~


Great find!


I have rehabbed a bunch of South Bays - and replaced a few sets of floorboards. As far as I have seen, the original floorboards were fastened into the wooden beams that stiffened hull laterally. I think I have mostly seen screws used - most rusted by the time I see them.


It seems that the floorboards were made of marine plywood - half-inch, I think. At least some have a hole bored just forward of the rear cockpit to allow access for a bilge pump - the old-fashioned kind that used muscle power.



The only problem I see with the permanently fastened floorboards is the inability to remove them for (annual) cleaning. Lots of rotted Salt Hay, rusted shotshells and old lunch wrappers can hide there - along with mud and sand.


One other problem is with their shape. Although cut at an angle at their corners, many of the stock floorboards chafe against the inside of the hull.


I have posted several South Bay "spa treatments" and other rehabs here in recent years.


I 1) trim the floorboard to a shape that conforms to the curve of the hull; ) sometimes add "curbs" to keep gear from bouncing aft when under power; 3) make them removable with a set of 4 wooden turnbuttons; 4) cut an access hole for the bilge pump; and 5) often finish with an anti-skid.



View attachment sm P - Gas Tank and fwd turnbuttons.jpg



This shows the OLD and NEW. Whenever I can, I have re-used the original floorboards - and just re-cut them. Everything gets sealed with 2 coats of epoxy before the new paint goes on.



View attachment Floorboards 01.JPG



On a different topic, lots of South Bay guys want a bigger spray shield. I made this jig so I can mold them both wider and taller. Here I have laid up an "extension" to add about 8 inches to the height. The widest shields go rail-to-rail.



View attachment Spray Shield 01.JPG



Here is the new "wider-and-taller" shield - with 2 rows of thatch rails.



View attachment Port 31 - spray shield.JPG



Finally - it looks like you need a motor board. I have made over a dozen of these for South Bays. Plenty of photos in process and installed.


View attachment Port 28 - stern quarter flap down.JPG





Hope this helps!


SJS


 
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Paul,

I plan to make the exact changes you mentioned and have the floorboards ride the boats ribs. I found it odd that the boards are secured with fasteners to the ribs. I've only hunted in one other SBDB and that boat as well had its boards screwed down, led me to believe it was either factory or common practice.

This south bay is new to me, have not had a grass boat for several years my last one rotted out sometime in high school or college. I was fortunate enough to grow up in a SBBD and a few other home made boats and garveys. Not much needed to get this one back working, the list of to-do's includes rails, doors, and an outboard bracket. I am also considering doing the topside in non skid for the pup.
 
Steve,

I find myself studying your posts, the information you have made available is invaluable and a great resource. I have some very dry PT lumber and plan on making a motor board of your design allowing for drainage. The floor boards will be coming out this summer and the pinholes into my stringers will be sealed, more than likely a good cleaning and acetone bath for the inside prior to fresh grey paint as well.

Lets talk doors, it seems their has been many different styles and ideas previously posted. This boat never had doors, there used to be a grass rail around the combing of the opening instead. I have also seen that some SBDB sport some very large yet low profile canvas dodgers and blinds.

I plan to give this boat doors but would like to add some additional overhead cover. I am thinking lower door on gunning side, higher door on up wind side with some overhead addition of sorts.
 
The floor supports, Not sure you can call the ribs. Were 1 x 2 glassed in place.
There were 2 long plywood pieces that had 1 x 2 nailed to the bottom and lined up the ribs.
The plywood had 1 x2 nailed to it, but they did not nail the plywood to the ribs they used screws for that.

If you are going to rebuild I would add more ribs for sure.
 
My cross supports were water logged and starting to rot. They were random lengths of 3/4 plywood 2" wide by 6" -10" long . There was alot of flex in the floor so I cut out all of the supports and removed the wood and cut 3/4" x 2" azek and glassed them in, added the extra supports. Cut 1/2 plywood for the floor boards coated with 2 coats epoxy and used the turnbuckles to hold down like Steve does.

I also opened up the cockpit and added fiberglass shield and flaps. without grass and grassed up


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Good morning, Luke~


I just wanted to make sure that you saw my recent post about mounting flap boards - intended mostly for you.


Also, just in case you want to re-shape your floorboards, here are the half-breadths I use. The locations for the turn buttons are approximate. They need to be carefully aligned with the floor frames.



View attachment South Bay Floorboards - measurements.JPG



All the best,


SJS



 
Bill I just redid my floor boards that way this past fall , put two 1x2 stringers screwed to the floorboards halfway between the stringers in the hull so the floor boards were sitting level on the stringers attached to the boat and the stringers attached to the floorboards ,also the hull underneath the floor was painted with bilge coat epoxy paint which gave it a smooth clean finish ,floorboards were then attached to the ribs with 4 ss screws on each side ,previous floor had a dozen screws hole that were epoxied up and sanded, had no problems this year with floors coming loose ,4 screws and they can be taken out for cleaning
 
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