Hard Top DIY Bimini & Dodger Materials?

[Tspringer]

Hello!

The Bimini top and dodger top section for our 2005 Beneteau 473 are worn out. Threadbare... sun shows through... goners and need replacement!

So I plan to build "hard" fiberglass replacements.

The concept here is to have the new hard Bimini and dodger top to be custom built to fit the same space and location as the sunbrella pieces that they will replace. The new hard Bimini top and dodger top will mount to the same typical alloy tube frames.

The new pieces must be strong but very lightweight. There will be no need to walk on the new pieces and only lightweight semi-rigid solar panels will be mounted on top. Both the new Bimini and dodger top will utilize new sunbrella and isinglass enclosure panels that I will also build.

So the key factors for the new hard pieces are lightweight - strong - easy to work with.

My thoughts are to use a flexible foam core to mount to the frames and then reinforce with fiberglass. What core material this will be is one of my primary questions.

What are the best core material options? Where can these options be sourced?

What options are there for pre-finished sheets that can be bonded to the core to simplify construction?

I have a good bit of fiberglass and construction experience but an not up to date with all the best current options. The end product will be solid, white in color with a nice surround and it will be as simple as I can make it.

Thanks!


Terry

[Bowdrie]

Ok, this is probably not quite applicable to your needs, but just 2>3 weeks ago I came across what could be called a "thinking outside the box" solution for a hard-top bimini.
It was one of those fiberglass "bed covers" for a pick-up truck.
I don't recall the exact size, for a full size truck it would be ~6'x8'.
I would like to see more camber for sake of appearence, but properly supported and rigged who am I to judge.
For a "shapely" bimini, yes, it would need to be done over a form/mold for the inner/lower face, then "scored" foam glued on, then the exterior glass work.
I think it would be a laborious project, vacuum bagging preferred.
Then it would still require a lot of screeding/filling/fairing, and then the work of some kind of 2-part finish.
Also, built-in "hard points" for hardware/mounting attachments.
Having nicly rolled edges and trim further complicates construction.
Taken as a whole, certainly not a project for the faint of heart.
I might consider a hard-top built as a "cold-molded" process out of epoxy and thin veneers, with a light glass covering on either side.

[Allied39]

I think there is a few threads on this already, likely a lot of base info there.

I had one running till I lost interest after having an idiot troll continually posting , but i can certainly vouch for the awesomeness of hard bimini and dodgers. Absolutely adore mine.

[coopec43]

Why not use the existing frames then cover them with "bendy plyboard" then f/g it with two layers of CSM/resin?




I've tried uploading a photo of "Bendy Plywood but it doesn't work. Try this



https://trademaster.com.au/product/b...1200x2400x4mm/

[nuku34]

I made a hard dodger for my Cavalier 32 berthed in Nelson NZ. I used 3mm "bendy plywood" as the core. I tied the ply to the existing S.S frame of the old canvas dodger with pieces of fine wire ("stitch and glue" method). The ply was temporarily attached to the cabin sides. The exterior was then covered in fibreglass cloth and carbon fibre (in some areas) and epoxied. Eventually when the whole dodger was shaped, I removed it and applied cloth, carbon and epoxy to the inside. Result is strong (I can walk on it) and light. Its a lot of work, especially fairing and painting, but looks fantastic and will outlast me.

[nuku34]

Photos of my hard dodger in process are attached

[mvweebles]

Back in the days before Project Atticus hit the big-time to have sponsors and patrons pay for their work, they used to do it themselves. Building a hard-dodger was one of their more interesting projects and is fairly well documented. They opted for just the top being hard, sides and front being soft/Sunbrella, which makes sense to me. Easier to fabricate, and allows more flexibility for airflow. The side panels would be relatively easy to sew-up and attach using awning-track.

https://www.youtube.com/watch?v=XoNUowUE1uE

[Bill O]

Would use 3/8" structural PVC sheets, bend in position and then glass over. Once set would take off and glass inside.
This structural PVC is similar to Divinycell H, but 1lb lower density and much cheaper cost.

[deltaten]

Tpspringer;
Not to be a wet blanket; but just some points to consider....

Will the "top" panels be (easily) removable/ stowed?
Canvas can be removed before a blow or for off-season storage while not present to watch/care for.
Even flat or slightly curved tops may become aerodynamic "wings" and generate considerable lift.
Will the tubular structure below be strong enough to deal with both down and up pressures and load?

Consider the interface between hard top and soft sides. How to attach snaps/zippers in an way to lap top over side to keep water out? Could become quite convoluted to produce in frp.

Cost/time calculation between frp and cloth replacement? I have done both frp and my own canvas work. Designing, fabricating and finishing an frp product is far and away more difficult than sewing new canvas panels.
Foul up on the front design or application and it's cut, grind, sand and rebuilt; hoping ya have it right this time. Lots debris, sweat and itchies. Mess up canvas and simply rip out a seam or sew on additional.
Your existing top lasted 17 years. Do you think new cloth replacement will last less?

AFA diy skills...I have pretty much your background. 40 years in the construction trades. I found no difficulty transferring those skills to the new art of sewing, using the helpful SailRite video as guides.

Either way, you get the same sense of pride in accomplishment.
I wish you well on your project, whatever you decide to do.

Sincerely, and hopefully helpful,
Paul

[wrwakefield]

We have been considering building a hard dodger and bimini for several years now. We have collected ideas over time and collated them on this page if you are interested.

Cheers! Bill

[vpbarkley]

There are a number of cruisers on YouTube who have made their own hardtops. I would search there for illustrated DIY instruction. You would be able to compare their results.

The following has some limitations but is expedient:

You could apply release agent on your bimini and dodger, then fiberglass over them. When you have sufficient stiffness you could remove the old Sunbrella material.

There would be a lot of fitting out - attachment, glazing, etc. Just a thought.

[Scubaseas]

Originally Posted by wrwakefield

We have been considering building a hard dodger and bimini for several years now. We have collected ideas over time and collated them on this page if you are interested.

Cheers! Bill

Thanks for sharing this. Hard top Bimini is on my to do list also. Greatly appreciate the info you have here.

[Kd9truck]

I to aspire to building a hart top dodger my cockpit and push pit are very large 11 x 11 so a hard Bimini I feel would only work if the vessel stayed put in a protected slip.

I did just build a sunbrella dodger and Bimini, it’s my soft proto type.
There is a lot of great contabutions already listed here so I will offer 1 thing.

Unless you have your vessel parked in your shop, or a slip in your yard, build an exact replica of where it is going on you vessel in your shop. And include everything that is with in a foot from your attachment points.

I was an hour away from my vessel and the back and forth wore thin after a while.

[rslifkin]

Originally Posted by Kd9truck

I to aspire to building a hart top dodger my cockpit and push pit are very large 11 x 11 so a hard Bimini I feel would only work if the vessel stayed put in a protected slip.

I did just build a sunbrella dodger and Bimini, it’s my soft proto type.
There is a lot of great contabutions already listed here so I will offer 1 thing.

Unless you have your vessel parked in your shop, or a slip in your yard, build an exact replica of where it is going on you vessel in your shop. And include everything that is with in a foot from your attachment points.

I was an hour away from my vessel and the back and forth wore thin after a while.

You could build a hardtop that big, but you'd have to pay attention to weight. So it would likely need to be foam cored. And you'd need fairly hefty mounting, but as shown on powerboats with hardtops that size it can be done.

The biggest concern with a big hardtop on a sailboat in my mind is the question of "what might fail in a knockdown?"

[PuttingDoctor]

I had a hardtop / Bimini system built years back for my Irwin 38’. I got the last WaveStopper made before the inventor passed away. He used molded polystyrene for the tops and regular canvas type tubing for support. The result was very attractive. Once installed my canvas man added his touch. The corners of the Bimini Isenglass were very solid an not removable though the center panel was.