Flybridge hard top

[ksanders]

I've contracted with my local stainless steel expert to build a hard top support for my Bayliner 4788

Now it's time to decide exactly what to have him build.

What I have is an existing Radar arch. That will stay, and the hard top will extend foreward.
What I want to do is add windows on the front, and the sides. The windows on the aft part of the sides can roll up.

The idea of the hard top is/was that the stainless guy would fabricate the metal, and then I would cover the hard top with starboard like my friend did in the attached photos.

But... what if i had the metal guy just finish the job with sheet stainless steel? I need to figure out the weights but starboard isn't light, would stainless be lighter or heavier.
Would it look funky?
What would you do?

Here are some photos of my friends hard top, and some good shots of my flybridge

 

[rslifkin]

I'd personally prefer fiberglass over stainless sheet. Easier to mount things to, and if you make it a cored fiberglass panel it would be quieter in the rain. Stainless or thin, un-cored fiberglass will be very loud when it rains. And as you mentioned, Starboard is heavy.

 

[ksanders]

I'd personally prefer fiberglass over stainless sheet. Easier to mount things to, and if you make it a cored fiberglass panel it would be quieter in the rain. Stainless or thin, un-cored fiberglass will be very loud when it rains. And as you mentioned, Starboard is heavy.

Yes, starboard is about 2.5 lbs a square foot. That's not really all that bad for my boat but... Maybe something better???

Sheet stainless or alumanium is certainly dooable but... yes it can be loud, but also once it dents, it's dented and stays that way.

Fiberglass or coosa board, with fiberglass is going to involve a custom built mold, and a ton of labor hours.

hmmm

 

[Comodave]

Starboard isn’t structural either. Having a thin Starboard top will bend and sag unless you have a lot of metal supports, equals weight. As I remember the 4788 is a bit tender to begin with so I wouldn’t add anymore weight than absolutely necessary. I would contact Atlantic Towers. They make hardtops to fit the exact boat. I had them make a hardtop for a boat I had about 6 boats ago. They found a local boat and went and measured it so the top fit perfectly. It wasn’t structural but it was aluminum and a fiberglass top. It was well made, but not cheap.

If I were going to make a hardtop from scratch I would layup a fiberglass top using carbon fiber or something lightweight but strong. I watched a video of a guy doing just that. He made a mold and then used vacuum bagging to lay it up.

 

[Graeme Walker]

I would extend beyond the arch ~3-4' to get more shading, we did this with our Sunbrella and it looks great.

 

[ksanders]

great idea extending beyond the arch!

 

[ksanders]

Well, we have solved one hurdle...

The fabricator will weld a stainless plate between the tubes circled in the photo. That will provide an attachment point for the side and front windows.

Now the issue is what to use to cover it.

Nobody seems to like metal.

 

[Graeme Walker]

great idea extending beyond the arch!

In our case it gives area for two more solar panels.

 

[Mac2]

I went through the same process as you. I already had the framework (aluminum) in place with a canvas bimini. I was going to go with aluminum sheeting over the frames, but then discovered you could “weld” the seams/joints of starboard. I bought 1/4 inch 4 x 8 sheets of starboard-I had substantial framework, so the starboard wouldn’t sag. My plan was to mount solar on top, but found out the panels would work better with more ventilation underneath. I ended up mounting the panels directly to the frame with u-bolts.

 

[ksanders]

I went through the same process as you. I already had the framework (aluminum) in place with a canvas bimini. I was going to go with aluminum sheeting over the frames, but then discovered you could “weld” the seams/joints of starboard. I bought 1/4 inch 4 x 8 sheets of starboard-I had substantial framework, so the starboard wouldn’t sag. My plan was to mount solar on top, but found out the panels would work better with more ventilation underneath. I ended up mounting the panels directly to the frame with u-bolts.

Thanks!!!

Is welding starboard similar to plastic, where you use a heat source like a soldering iron and a filler plastic?

 

[Mac2]

Thanks!!!

Is welding starboard similar to plastic, where you use a heat source like a soldering iron and a filler plastic?

It is a special tool that looks like a heat gun and you buy a coil of plastic/starboard wire. I recall it comes in different diameters depending on how thick the weld needs to be. There are commercial grade welders and cheaper versions like what I got. I never got the chance to use it, so can't verify how well the cheaper versions work. I had a commercial guy lined up in case I failed. Keep in mind, just like metal, I had the starboard edges, where I planned to weld, cut at a 45 degree angle. If you ever get to Seattle, I got a deal for you....

 

[ksanders]

It is a special tool that looks like a heat gun and you buy a coil of plastic/starboard wire. I recall it comes in different diameters depending on how thick the weld needs to be. There are commercial grade welders and cheaper versions like what I got. I never got the chance to use it, so can't verify how well the cheaper versions work. I had a commercial guy lined up in case I failed. Keep in mind, just like metal, I had the starboard edges, where I planned to weld, cut at a 45 degree angle. If you ever get to Seattle, I got a deal for you....

Thanks!

 

[SIBERNUT]

When you fab either the tube or the hardtop, watch the forwardmost corner. Wherever you plan to mount the glass on that spot, be sure it is AFT of a vertical line down to the corner of the windscreen or wherever the lower edge will be. If the hardtop corner is forward of the lower corner , you will have a wrinkle in the glass that will be permanent , from top center to lower outer corner.
If im not clear here, pls PM. me

 

[rslifkin]

As far as building a fiberglass top, I've thought about how to do it for my own boat without a mold. I'm thinking of making a something to give the basic arch shape and hold foam to that shape. Glass one side of the foam, flip it over and glass the rest, then finish work. Should be easier than a mold for a one off.

If you want a flat top, even easier. I've done flat foam core panels on a table with a trash bag spread across it before.

 

[SteveK]

@Mac2
I see you used rigid panels. Did you caulk between them to stop any leaking from rain?
I have a standard bimini framework and have wondered about mounting directly on that.

 

[Comodave]

I put hardtotop.com hardtops on several boats but I believe they went out of business during the pandemic due to parts shortage. They were a simple lightweight hardtop. You would use the bimini frame to support the hardtop. The top was made out of translucent honeycomb plastic that you attached to each other and the frame. You could get aluminum keder stripe to attach an enclosure to. I used to fabricate my own enclosures. But on one boat I had a commercial fabricator make the 7 front panels out of EZ2CY. That is amazing stuff, like looking through glass. I templated the panels and sent the templates to him and he made the panels. I had him make the middle 3 panels hinge up and hook to the bottom of the hardtop. Worked extremely well and fit perfectly. That was a bery larg hardtop and it was too heavy for the 1” S/S frame. So i had 1.25” bows made and then the hardtop was rock solid.

 

[psneeld]

A friend covered his bimini frame with sheets of starboard like material from Lowes or Home Depot that was much lighter/less expensive than standard Starboard (with many similar characteristics). I think Starboard had a lighter version too.... like this stuff is a mix of Starboard and styrofoam. Seen to work well for him on his 45+ foot catamaran (really wide cockpit).

I had a hardtop frame with the thin fiberglass sheathing made for my sportfish. Loved it and it really wasn't all that loud as usually the wind/rain beating off the clear vinyl and boat in general was loud enough that the rain hitting the thin panel didn't matter. It was the lightest option and actually lighter than the material top which I despise on boats for maintenance/longevity. To mount a radar and crawl out to it, aluminum bars were in the frame to allow that.

After all the boats I have run and spent time on in all kinds of weather....and the boat I was going to outfit wasn't set up for a heavy hardtop. I would just use the fiberglass skin. Light, inexpensive, easy to mount/replace if necessary... no real downsides maybe except noise in a storm when I would probably be at the lower steering station for anyway. If on the bridge to watch the thunderstorm during happy hour... a slightly stiffer drink adjusts my hearing anyhow.

 

[ksanders]

This another boat my fabricator showed me that he had just completed.
It shows his style of construction

Now imagine how to connect side panels to this? Pretty difficult?
What we are going to do is to have him fill the gap between the two hotizontal tubes that go around the perimiter with plate stainless.

Now we have the ability to easily attach and detach when needed side panels with clear plastic glass.

The front will be the same and the slope of the front "windshield" will match the slope of my pilothouse windshield.

Now how to attach a roof?

The fabricator will weld in plate stainless in places along the perimiter, but on the inside to allow the roof to be through bolted to the structure.

As to the roof material...

I am leaning very heavially towards starboard. This stuff is indestructable, will bend to the light curve of the top, and would look nice with a 2-3" self supporting drip overhang around the perimiter.

You can "weld" starboard, but I am not totally confident with that process, and am thinking the stainless guy would fabricate a flat trim piece to be attached at the seams to assure no leaks in the rain.

 

[psneeld]

One issue with Starboard is it expands and contracts quite a bit with temperature.

Another captain used it for covering the dash of one of out 42 foot towboats and we were disappointed with the gaps/buckles and pulled screws.

Mat want to contact a distributer or manufacturer to see what their recommendations are. Some installs may be fine...but depending on singular piece size, fastening method, board thickness, and framing may all facture in.... also color. White may be far better than all other darker colors.

Not to be discouraging...just info I have come across.

Saw this on the internet...

---

Does King StarBoard® expand and contract? Yes, at a rate of 6×10 -5 in./degree F, changing approximately 1/32 inch for every foot of length or width over a 40-degree temperature change.

and this.....

• Use standard fasteners with oversized holes. Drill pilot holes first, followed by an oversized hole to allow for expansion and contraction.

 

[Mac2]

@Mac2
I see you used rigid panels. Did you caulk between them to stop any leaking from rain?
I have a standard bimini framework and have wondered about mounting directly on that.

I used bed-it-tape (on side of frame) from 'Marine How To" along with caulk (uv stable) in the bigger gaps on top (usually at the arc). Caulk is not pretty, but it is on top and can't be seen. I had one very small leak. I believe it was the panel itself-between glass and frame. It was small and has since sealed itself. More likely dirt filled the small seam. I have 1.5 inch tubing mounted to 2.5 inch down supports and it was designed to hold snow, so the canvas wouldn't sag. The panels will have the weight listed, so you can figure out if you need to add additional support.

 

[Mac2]

You can "weld" starboard, but I am not totally confident with that process, and am thinking the stainless guy would fabricate a flat trim piece to be attached at the seams to assure no leaks in the rain.

That was my plan with starboard, except I was going to use starboard strips. I would have welded the seams (probably 1/2 wide after cutting edges to 45 degrees) and put butyl tape (bed-it-tape-designed for Marine use) on top of the weld and then place the strip on top of that and use screws to hold in place (not penetrate the starboard). Starboard will sag in large gaps, but you will be able to add supports as needed. I can't recall how I found the professional plastic welder I was going to use, but it might be worth making some calls to the pros to find out their experience with starboard over time.

 

[ksanders]

I have more information...

I just got off the phone with King Plastics, the ,manufacturer of Starboard technicial information department.

The representative told me the original King Starboard is a perfect choice, and 1/2" would be the appropriate thickness for my top.

He told me that any plastic product will expand and contract with temperature changes. The best practice for a large sheet installation is oversize holes, and to use rubber washers to seal the bolt holes against rain intrusion. He specifically recommended against counter sinking bolts to achieve a smooth look.

As far as joining sheets he recommended either mechanical bonding of the sheets to not be able to seperate, then covering with trim, or welding the pieces together with a HDPE welder, which he said is available online from a variety of sources.

He also refered me to this deflection guide which shows the maximum deflection with a single point load for various thicknesses and distance between supports.

Remember this guide is for a single point load placed dead center between the supports,

https://www.kingplastic.com/wp-content/uploads/2014/05/Load-Deflection-Data-HDPE.pdf