Bridgedeck Project

[AdriftAtSea]

Also, when we added the bridge deck on the other boat, we found it gave us MORE room. More sitting room in the cockpit and more room inside the boat. So it's a difference for sure, but it's really not terribly inconvienient.

That's kind of what I was hoping would be the case on my boat. :D

[Frank]

Both the ariel and suncat had bridgedecks...the flicka's is so short its useless.I quite liked that larger erea and found it handy for many things..charts,wine,sitting,wine,cooking,wine,books,wine and a variety of other wine based functions   ::)

[BobW]

Cmdr Pete -

Thanks for the comments, link, and pics.  Gives me another perspective and something to think about.  Last night when I Googled "sea hood," one of the hits was the link you included with your post.

I realize a sea hood will marginally reduce how far forward the hatch cover will slide.  But I already bump my head on the hatch cover, particularly when I forget to stow the padlock!

Charlie -

Enjoy the Duckworks Messabout!  Yes, I remember the beach and the cabanas just 5 blocks from your place.  Hopefully, the weather cooperates and it'll be a great weekend.  Take and share lots of pics.  :-)  The sketches and your input can wait.  I'm not building this project this weekend!

[CapnK]

...and a variety of other wine based functions   ::)

LOL, Frank! Gotta have priorities, right? ;D

[AdriftAtSea]

Got started on the bridgedeck today... bought 3/8" plywood for it and cut it up for the two major pieces of the bridgedeck.  Originally, I was going to have the bridgedeck be the same height as the cockpit seats, but have since decided it would be easier and better to have the cockpit be the same height as the cockpit step, rather than the bridgedeck. This way it'll close off less of the companionway, and be easier to build.  I'll post some photos once I've gotten it roughed in. 

[BobW]

Dan,

Glad to hear you got the project started.  Looking forward to more on your progress - construction details - and the pics.

[CapnK]

Yes, Dan - do post some pics. Try as I might, I can't get my head around your description, lol. I need to go look at some pics of the cockpit, maybe then I'll understand. :)

[AdriftAtSea]

Capn K-

If you look at this photo, you can see the water deck fill on the second step.  The port first step has the port genoa sheets piled on it... that would be the level of the bridgedeck I am planning on building, instead of making it as high as the cockpit seats...which is about six inches higher than the step.

I hope that helps a bit.

[AdriftAtSea]

Well, played hooky from work today to get started on the Bridge Deck project.  Here are two photos of what I've gotten done so far.  I still have to screw the cleats to support the structure in place, and then glass it in, but this should give you an idea of what I'm doing. 

The structure in the photo is not going to be the final Bridge Deck, as I am going to do something slightly different for the final installation.  Instead of using the smaller piece you see for the top of the bridge deck, I'm going to use a single 1/2" sheet of plywood that goes all the way across, and fills in both step areas... as this will add a lot of strength and rigidity to the cockpit area and help reinforce the aft aka beam. 

However, it still means moving the deck fill for the water tank, but that was going to be the case any way I did it.  I hope this clarifies what I meant by making the bridge deck the height of first step, rather than the cockpit seats. 

I will be installing the cleats and hopefully glassing in the whole thing on Saturday. 





I also have a photo of my cockpit stereo speaker installation.   

The speakers aren't behind deckplates as I originally planned, but the space they open over does not let water into the boat, but into the rudder quadrant space, and doesn't really cause any danger of flooding, if the speakers should be punched out if the cockpit gets pooped.  The stereo system has a cockpit mounted waterproof remote, which you can see on the starboard cockpit seat.

[BobW]

Dan -

Looks good. 

How wide is it between the seats?  Good idea to run that top piece all the way across the steps.

Do you plan a frame or other support in the middle?

I'd like to extend the top piece on mine across the top of the seats but then I'd have a ridge on the seats...unless I could fair it into the seats...  I'll have to give that some thought. 

[AdriftAtSea]

BobW-

The top piece in the photo is 48" wide.  I'm not going to use a frame, but if you look in the companionway, you'll see that there is a 5" piece going across the companionway, which will be epoxied and glassed to the top piece as well as the companionway frame itself...so that should provide plenty of support and eliminate any need for a frame or support in the middle.

I only thought of running the piece all the way across after seeing how the preliminary model worked out.  By running the top piece across the entire width, I gain a inch of height in the locker, reinforce the boat for the ama-related stresses, and eliminate the need for putting in cleating blocks for the top, since it is fully supported by the steps already—simplifying the installation.

I am going to epoxy coat the top board, which will be 1/2" plywood and then glass it in as the first step.  It will be glassed in to the top of the steps as well as to the lower steps underneath. 

The companionway piece will be a 1/2" piece of plywood which will be routed along the edges, so that it is flush with the interior of the cabin side of the companionway.  This will be the second step.  It will be glassed to the back and front of the companionway, as well as the top and bottom of the deck piece.

The last piece will be the slanted piece that seals off the cockpit from the bridgedeck/locker.  I plan on installing cleats on the port and starboard sides as well as one on the cockpit sole.  These cleats will be made of either Starboard or composite decking material.  They are going to be temporary, until the external glassing and epoxying is done.  I plan on glassing the interior after removing the cleats. 

The last things I have to do are to figure out how to extend the deck fill for the water tank up through the bridgedeck and what kind of closure/doors to install for the new bridgedeck locker in the cabin.  I also have to either paint or gelcoat the bridgedeck.  Originally, I was thinking of gelcoating it, using a mold I'm going to make of the non-skid surface of the same pattern as the cockpit sole, using a silicone mold.

[AdriftAtSea]

Well, the fiberglass and other supplies I needed to start glassing in the bridge deck arrived UPS this morning, so I'm off to the marina to start on the installation.  I hope to finish most of it this weekend.

[BobW]

Dan -

I'll be interested to see how your plan works.  The distance bewteen my cockpit seats is about the same as yours.  I was/am planning to use at least one frame and maybe two to keep the top of the bridge deck from flexing too much.  Maybe I don't need to worry about that... but it will be walked on and sat upon so I want it to be sturdy.

Post pics of the progress.

[AdriftAtSea]

BobW-

Since, I couldn't find a piece of 1/2" plywood that I liked, so I ended up using a piece of 3/4" plywood...technically it is 23/32"—whatever. 

This should stiff enough to bridge a 48" span and support pretty much any weight I would put on it... given that I am fiberglassing over it and adding a lip to the companionway edge of it and supporting the aft edge of it by the aft panel of the bridge deck locker—effectively making it an laminated angle, rather than just a flat span.

According to the Sagulator, a 5.5" x 23/32" x 23" plywood board on edge—which is the measurement of the companionway edge coaming—will deflect less than 0.01" under a 500 lb. load.  The aft bulkhead of the bridgedeck is a 5.5" x 3/8" x 29" plywood board at a 17˚ angle from vertical—and if it was vertical it would deflect 0.04" under the 500 lb. load.

Several people I've spoken to about it have said that 1/2" plywood would have been more than sufficient for the job, and 23/32" plywood is going to be overkill.

For the lamination process—I am adding three layers of 6 oz. fiberglass cloth to the bridge deck top surface, and two layers underneath.  I plan on using three layers of 6 oz. fiberglass cloth on the aft bulkhead as well. The joints will be filleted with thickened West Systems Epoxy.  The top board will be bedded in thickened epoxy with the edges filleted in as well. Each panel will be laminated to the cockpit on all four sides—effectively creating a hollow  three-sided beam across the front end of the cockpit.

Today, I sanded the gel-coat in all the areas that will be laminated over as well as removing the non-skid surface from what will become the interior of the locker. I picked up a Hitachi random orbital sander to do the work with—it's worth every cent.  I also finished cutting the top piece of the bridge deck to size.

[BobW]

Dan -

Those numbers are convincing.  Makes me rethink the need for frames to support the top piece.

My original thought was to use my bridge deck as a cockpit locker inaccessable from the cabin.  That means adding a hatch with attendant hardware.  I may change that plan, eliminate the hatch and hardware, and take advantage of the storage.

Thanks for the information.  I'll look forward to the pictures.

[AdriftAtSea]

BobW-

Got the bridge deck top board glassed in with the first layer of glass.  I wish it were warmer, since the epoxy is taking forever to cure. 

Unfortunately, I won't be able to work on the project for a couple of days... which means I have to wash the amine blush off the epoxy and sand it lightly before I can continue. 

I also cut the companionway rails down to fit the new, shorter companionway. It looks like it will come together nicely. 

Next time I go out to the boat, I will add another layer of glass to the top, add a layer of glass underneath the top, and install the three temporary cleats that will support the angled aft panel of the bridge deck.  If the epoxy cures enough, I will do the second layer underneath and the third layer on the top.

I'm still debating on how to finish the top.  Right now, I'm leaning toward going with a polyureathane paint, instead of gelcoating it. I still have some time to decide though.

[BobW]

Dan -

You are making great progress!

When you commented earlier about glassing both sides of the plywood I pictured you glassing before installation.  I haven't much experience with fiberglass, so I am at a loss to understand how it is done on the underside of a panel.  Help me out with a description of that process, please.

I'm just a bit jealous as a few small emergencies have kept us from getting out to the boat to work on it.  While it feels like time is slipping away, life is too short to get worked up about delays to my boat projects.  We'll get out there and get everything done... it'll just take a little longer.

[AdriftAtSea]

BobW-

While I could have just fiberglassed the exterior of the board, it would not have contributed as much strength to the installation as laying the fiberglass up into the existing cockpit surfaces.  For the bridge deck top board to flex, it now has to flex the entire cockpit—which really isn't possible.  Likewise, for the cockpit to flex, it has to now bend the 7/8" thick cored laminate bridge deck top panel.

A good way to imagine what I am doing and why is to think of making a very simple wooden bookshelf...

Cut a sheet of 1/2" plywood into eight 4' x 1' wide strips.  Take two of them and use them as vertical supports.  Now attach three of them as shelves, spaced  every 23.5" using simple butt joints and nail them through the vertical sides...

It is a book shelf with three shelves, but not one I'd put much weight on.  Also, if you were to push on the top from the side, the thing would not stay square—as it currently is the bookshelf won't resist lateral forces very well. The shelves are dependent on the strength of just each sheet of plywood not splitting where the nails enter them and probably don't support all that much weight.  They also don't have any way to resist lateral forces very well.

Now take some thin sheet metal and cut it into strips that measure 3" x 12".  Make 18 of these strips and bend them in half length wise and make right-angle braces out of them. Now use twelve of these braces of sheet metal both above and below the shelf, and nail through the sheet metal into the vertical supports and the top and bottom of each shelf.  All of a sudden, the shelves aren't dependent on just the physical limits of the plywood not splitting to bear the weight... it is a much sturdier shelf.  But it still doesn't resist lateral forces all that well—as not of the components of the shelf can resist the lateral loads in torsion. 

Now, take one of the remaining boards, and put it along the center of the back side of the bookshelf and attach it to the three shelves using the remaining six small sheet metal braces.  Now the bookshelf is even stronger at resisting weight on the shelves, since they're now supported in the middle as well as the ends...and the entire unit can resist lateral forces much better since the panel going vertically along the back of the bookshelf resists lateral forcdes in torsion.

By epoxying in the board and then adding fiberglass that covers the board and attaches the board to the exisiting cockpit, I've effectively created the same type of support—where the fiberglass acts as the sheet metal braces in the example above.  However, to do this, the glassing has to be done with the board in place, which makes the glassing of the board a bit more difficult.

This takes the open cockpit step area and converted it into a large box beam—with two of the four sides being from the existing cockpit—that of the forward bulkhead/companionway and the sole, and two from the bridge deck installation, the aft cross panel and the top cross panel making up the four sides of a laminated fiberglass box.  The box beam can't flatten under load, since the cockpit sides, acting as ends on the box beam, prevent the box from changing shape under load.

The board is not only epoxied to the two steps, but filleted along the outside edges, so that the board and the existing cockpit have a solid thickened epoxy connection along the entire perimeter of the board, and then finally, the board is fiberglassed into the existing fiberglass, which was sanded as part of the preparation. I am taking the fiberglass and lapping it up against the sides of the existing cockpit fiberglass.  This will effectively turn the board in to an integral part of the cockpit, which can't be removed short of using an axe. 

The first layer of the fiberglassing extends up about 1-1/2" along the existing cockpit surfaces, and continues over the entire top surface of the bridge deck board.  The second layer will extend up about 3" and the final layer will go about 4.5".

On the underside of the bridge deck board, I am coating the board with epoxy and then adding a layer of fiberglass cloth to the surface... which will go from 1-1/2" vertically along the existing cockpit fiberglass, and then run along the entire lower surface of the bridge deck board and across to the other side and then down vertically  1-1/2" along the opposite side of the cockpit.  The second layer will extend 3" along each of the existing sides of the cockpit steps.  While this is not really necessary, and a bit overkill... it does effectively turn the plywood into the core of a 7/8" thick fiberglass laminated beam.

Then, the two other pieces, the companionway threshold and the aft angled panel will both be glassed in the same way. 

This also makes it far less likely that the bridge deck or bridge deck locker will leak at all.   

[BobW]

Dan -

Wow!  Didn't expect such a detailed explanation of the "why."  I appreciate the time and effort to provide the information. 

My question was really more mundane... How do you apply FG cloth on a horizontal overhead surface, particularly when working in such a restricted space?

I won't be starting my bridge deck until after completing the motor lift (no, no progress on that this weekend), but your experience and information will be invaluable when I do start.  Thanks.

[AdriftAtSea]

BobW-

The epoxy resin is fairly viscous and a thin enough coating will stick to the underside of the bridge deck board and will effectively hold the fiberglass to it.  Too much resin will cause it to sag and drip... so applying just enough to wet out the glass is the trick. The cloth adds support since I run it down the sides of the existing cockpit, and that helps quite a bit too.  I'm doing about half the depth of the cockpit locker at a time, one half at a time, so the glass I'm using is about 9" wide by 42" or so. 

BTW, was down at the marina today and got the aft panel in, with one layer of glass.  Unfortunately, I don't have the fast hardener, just the slow... and curing times are running a bit longer than I'd like.  If it doesn't warm up a bit, I might have to go get some fast hardener.  :D