Considering Building a Hardtop Bimini

[SoonToBe]

Hello,

The bimimi cover on our 37 Lagoon TPI cat is getting tired and worn out and needs to be replaced. It is currently constructed of an aluminum frame with a sunbrella cover. A visitor on our boat mentioned that he had made a hard cover for his bimin which was a similar design to our. With the width of the catamaran, it would be fantastic to be able to walk on the bimini when dealing with the main sail. It would also need to be able to incorporate a windshield, side and back shade covers and I would also like to incorporate a water catcher system. I believe the currentily structure will easily support a hard top.

Here are my questions - any suggestions would be appreciated.

How would I go about making a mold?
How would I form the "eavestrough" around the edge of the bimini to act as the rain catcher?
What materials should I use to keep the hardtop strong but light?
How thick do I have to make it?

Thanks in advance for any advice or direction

[maxingout]

When you get a design, I would also like to see it. We have had a bimini for our Privilege 39 for the past forteen years, and it has worked well. But we have thought about doing exactly what you are thinking about doing. Good luck on your quest.

[SaucySailoress]

Stop considering, just build it. Here's How:

1 - Order the solar panels you need to power your needs.
2 - Measure the solar panels.
3 - Have a heavy duty stainless frame built.
4 - Attach frame to back of boat.
5 - Use frames to protect electrical cables from sun etc.

Optional Extra:

6 - Make a stainless n shape. Hinge to base of frame.
7 - Have sunbrella cover made which can pull forward to make canopy (think good old fashioned street cafe)

[Hyprdrv]

I have yet to see a home made hardtop that didn't look home made. The process is quite an undertaking and since the structural integrity is high on the list I would consider going to a pro. There are 2 places here in VA that have done the French Lagoons with excellent results using the existing frame and incorporating solar panels.

Martin's Custom Structures of Gloucester, VA
and
Schroeder Yacht Services, in Deltaville, Va
I've seen Schroeder's work and consider it high quality. Martins was suppose to be cheaper but I haven't seen their work so can't yet compare the 2. I believe Schroeder's hard top was around $6k for a Lagoon 410.

Steve in Solomons MD

[islandguy5]

Originally Posted by SoonToBe

Hello,

The bimimi cover on our 37 Lagoon TPI cat is getting tired and worn out and needs to be replaced. It is currently constructed of an aluminum frame with a sunbrella cover. A visitor on our boat mentioned that he had made a hard cover for his bimin which was a similar design to our. With the width of the catamaran, it would be fantastic to be able to walk on the bimini when dealing with the main sail. It would also need to be able to incorporate a windshield, side and back shade covers and I would also like to incorporate a water catcher system. I believe the currentily structure will easily support a hard top.

Here are my questions - any suggestions would be appreciated.

How would I go about making a mold?
How would I form the "eavestrough" around the edge of the bimini to act as the rain catcher?
What materials should I use to keep the hardtop strong but light?
How thick do I have to make it?

Thanks in advance for any advice or direction

Did you ever do this to your cat?

[SkiprJohn]

Just do a search under bimini or hard dodger on the search engine after my signature. You'll see some solutions.
kind regards,

[CDunc]

The Questions you were asking is going to depend on what you will accept as risk.
as far as strong and light weight those are engineering questions and best bet is to hire an engineer or N.A. to design your hard top. The structure you Have may support the top as is but what about if you are on it, or you and your partner are on it, or a breaking wave crashes on it? Hire a Professional to do a preliminary assessment and design. Or take the risk as is.

[Cotemar]

This FB Belize 43 Fiberglass Bimini might give you some ideas.
http://www.cruisersforum.com/forums/...tml#post485328

Mark

[otherthan]

I went to a scrap yard and mesured severald models of old fiberglass pick up box...fund one with the right size took it home for a big $45...once the top cuted and sanded you cauldent say it was a truck box...only need to build the frame...for this I fund a damaged tempo car garage, free!
its galvanised 1in steel but hey the price is righté

[lookoutnw]

I did one for a friend and am thinking of doing it on mine. I will modify my enclosures bows a bit though. I did it by taking 'door skins' and soaking them and then strapping them to the bows on his boat. They dried, I then took some foam cord and cut it flat on one side a bit and glued it to the underside of the skins. I put 2 layers of glass on the top and 1 layer on the bottom after I built up the foam cord 'beams'. Tough and not too heavy either. We put 3 solar panels across the top and he is very happy with it. A lot of work but again, I am thinking of doing it to mine also. YOu may add a layer or 2 more of mat if you have large spanses and are looking at tromping heavily on top of it.

[CDunc]

another thought, look at the support poles, where do you think all the weight is going to be transfered, get the structure under the bases re-enforced and increase the bases so you dont put cracks or worse a hole in your coamings.

[ggray]

Missed seeing this thread last summer.

Your frame looks similar to mine, which was designed to support 2 men. The top panel the fabricator built was made of a material I think was called cell-tech, 1/2 " thick which is commonly used by the "tuna tower" fabricators.

Since it was a little heavy, and had to be made in 2 pieces because of the size, from the start I planned on replacing it with a one piece top that I would make of 1/2" Dekolite, which is fiberglass skinned end grain balsa. I had to join the 2 pieces with a butt joint covered with fiberglass.

To allow me to "reef" the top for huuricanes, etc.(on a cat, the top can be a very large wing), the out board 2 feet are removable Sunbrella. I glued a plastic boltrope track to either edge of the hard top. Also, with the cloth sections, it was easy to incorporate coverable windows either side for checking the set of the main.

It all works very well, and to my eye looks great. Oh, and the joint between the panels that I eliminated with the Dekolite was right at the the helm, so now I stay dry!