Fabricate hard Bimini for large cat

[dano098]

Hi all; it’s likely I’ll close on a Cat next week. It’s major defect is the lack of a foul weather helm.

Does anyone have experience with the fabrication of a hard enclosure? I’m in FL, and I would prefer to get the work done on the west coast, say Tampa and south.

Thanks in advance.

[s/v Jedi]

Originally Posted by dano098

Hi all; it’s likely I’ll close on a Cat next week. It’s major defect is the lack of a foul weather helm.

Does anyone have experience with the fabrication of a hard enclosure? I’m in FL, and I would prefer to get the work done on the west coast, say Tampa and south.

Thanks in advance.

I recommend you have the frame done in anything except stainless steel. The maintenance is a headache. Fiberglass or carbon fiber would be my preference because aluminum also becomes unsightly when not anodized.

[Cpt Mark]

Building a hardtop bimini and presumably dodger is going to be time consuming, expensive and worth it. However, like any project, the devil is in the details.

On my cat the mainsheet control went behind the helm seat at an angle to a deadeye that the caused the mainsheet to hit me in the back of the head. So, I wanted to move that up top on the hardtop bimini. That took a very long time to figure out the engineering so it would be strong enough to withstand those loads and no come off. Do you want solar panels up there? Where are your winches? You'll need window(s) above to see the sail most likely. You'll need a walkway to service the main when you need to. Do you want opening windows on the dodger? as you can see, the list goes on and on. Also pay attention to the height of the bimini top in relationship to the boom. If you are going to move the control lines up there it is important. Also, do you want standing headroom below the bimimni? Lighting....

[Fore and Aft]

SV Jedi fiberglass hard top and stainless-steel legs is a fairly common way to do it. I am not sure what grade stainless steel you're using but leg maintenance has never been an issue on our yacht. Even neglected boats I survey still have reasonable looking legs.
This hard top below is fairly basic, stainless-steel legs, roll down canvas curtains, solar panels on top and strong enough to walk on.
Dano098 building a solid top is fairly easy, the biggest issue I ever faced was moving the hardtop to the vessel. Often, we would hire a car trailer to deliver the hard top since for a catamaran they are so big. On our yacht the biggest mistake I made was building the hard top so light we can't walk on it.
Like Cpt Mark says there is going to have to be some serious brain storming between you and the builder to make sure you get it right.
Cheers

[Tin Tin]

https://www.biminihardtop.com/ I think they will ship it in a pack and you re-assemble - depends if it is a known brand/model.

[s/v Jedi]

Originally Posted by Fore and Aft

SV Jedi fiberglass hard top and stainless-steel legs is a fairly common way to do it. I am not sure what grade stainless steel you're using but leg maintenance has never been an issue on our yacht. Even neglected boats I survey still have reasonable looking legs.
This hard top below is fairly basic, stainless-steel legs, roll down canvas curtains, solar panels on top and strong enough to walk on.
Dano098 building a solid top is fairly easy, the biggest issue I ever faced was moving the hardtop to the vessel. Often, we would hire a car trailer to deliver the hard top since for a catamaran they are so big. On our yacht the biggest mistake I made was building the hard top so light we can't walk on it.
Like Cpt Mark says there is going to have to be some serious brain storming between you and the builder to make sure you get it right.
Cheers

Legs are fine, a frame that supports the fiberglass isn’t as salt builds up between the stainless steel and fiberglass where they touch.

[dano098]

Good morning all, Great ideas and issues I had not considered. Led lighting another thought. I’ll keep you informed. Survey end of the month. I’m probably getting ahead of my self a tiny bit. Thank you everyone!

[BenBowSirocco]

Dano: congrats on the boat.

Check out HiLine hardtops. https://www.atlantictowers.com/hiline.php


They are a hybrid construction, utilizing an aluminum internal frame covered by skins of fiberglass, the tops are very lightweight (which is always the #1 issue with tops in general) and make adding lighting, speakers, walking platform or whatever you need a simple process.

They can be produced in almost any size you need as well.



"The Yacht Rigger" (forum sponsor) is currently producing them and they are located in St. Petersburg Florida.

They can also help get anything else you need on the boat done: solar arrays, LifePO4 conversation, 24VDC Aircon, high output alternators.. etc.



Give them a call with any questions.

[Morph]

I built one for my 12m cat a few years ago-- fabricated it in foam and fibreglass and had stainless (316) legs fabricated and just bolted them on(with appropriate over drilling and backfilling of the bolts. Getting the measurements right is critical and obviously where you're going to faster the legs. It is not that hard, getting a good looking curved edge-- I used cheap flexible plastic piping and glassed it on-- with a fair bit of fairing it looked fine. Then it is a matter of what other attachments you want... do you want water catching? attachments for sun shades etc but all quite do-able. you just need to know how to laminate and bog and fair-- I didn't bother vacuum bagging it. Phil

[Tupaia]

Built mine, aluminium frame, etch primed and painted never had an issue with corrosion. The top was made from 16mm PolyCore, (5.4x2.2m 19kg) not something I would build a boat from but excellent for this application. Easy to trim with bolt rope channels top and bottom to allow for shade covers or clears. Check the access points where you leave and enter the cockpit, this can be a issue on retro fit biminis.

[The Yacht Rigger]

At The Yacht Rigger we recently took over production of High Line hard tops from Atlantic Towers - these are lightweight aluminum structures with a thin fiberglass sheet on top and bottom, using custom extrusion for the edges for a beautiful finished look.
This combination creates a lightweight but very attractive hard top. We can also integrate walkways into them where/when necessary.
Please feel free to reach out to us. info@theyachtrigger.com

[Miki]

If it was me I would utilise the actual solar panels as a roof with a supporting GRP frame around the edge for aesthetics. Why double up? Lightness is king for a cat

[MicHughV]

I built my own canvas bimini, but had the s/s frames bent elsewhere, because it requires a special tool to put the curves in. I can't remember that I paid for this service, but it was somewhere around $200 for a simple bimini top.
The various fittings, zippers, etc, can be sourced from any marine supply store.
The canvas, and it has to be the " sunbrella" fabric can be sourced from a variety of places.
After that, I used cardboard to mimic the shape and placed these on the sunbrella to allow me to cut out the shapes I need, allowing an edge for sewing, etc.
I also inserted clear vinyl " windows. As above, these can be sourced from a variety of places.
Then I bought a relatively cheap sewing machine from Walmart and stitched it all up, remembering to get the appropriate thread.

When you add it all up, it was a lot of work and money, and though the finished product looked ok, it was clearly not up to the standards of a professional done one.

Were I to do it again, without a doubt, I'd hire a canvas specialist to do it, and this is my recommendation to you.

[dano098]

Thanks everyone, I much appreciate the comments and suggestions. Let’s get by the survey and I’ll update. Cheers!

[Franziska]

Originally Posted by Fore and Aft

SV Jedi fiberglass hard top and stainless-steel legs is a fairly common way to do it. I am not sure what grade stainless steel you're using but leg maintenance has never been an issue on our yacht. Even neglected boats I survey still have reasonable looking legs.
This hard top below is fairly basic, stainless-steel legs, roll down canvas curtains, solar panels on top and strong enough to walk on.
Dano098 building a solid top is fairly easy, the biggest issue I ever faced was moving the hardtop to the vessel. Often, we would hire a car trailer to deliver the hard top since for a catamaran they are so big. On our yacht the biggest mistake I made was building the hard top so light we can't walk on it.
Like Cpt Mark says there is going to have to be some serious brain storming between you and the builder to make sure you get it right.
Cheers

Maybe you could consider adding a layer of carbon to your hardtop to stiffen it up.

Panel stiffness can improve considerably with this. That way you may get it strong enough for walking on it.