Kattoprojekti - Hard top bimini



Original idea

New plan, while driving

In harbour, camper sides on

Tähän kootaan valmistusvaiheita veneeseen tehtävästä kaikkein suurimmasta muutostyöstä. Tarkoitus on poistaa rättikatto, ja valmistaa biminikatos lasikuidusta. Samalla veneeseen tulee targakaari, joka tietysti tarvitaan kannattelemaan kattoa, mutta onhan kaaresta sitten muutakin hyötyä.

Syy tähän on se, että yökasteen ja sateidenkin kostuttama rättikatto alkaa homehtua aina loppukesästä. Sitä pitäisi ehkä suojakäsitellä pitkin kesää. Ei vaan jaksa. Ja sitten, kuomu pitäisi ikänsä puolestakin uusia ehkäpä muutaman vuoden päästä.

Valmistus aloitetaan valmistamalla puusta mallipalat (eli lestit) osille. Sitten lesteistä valmistetaan lasikuitumuotit, ja tämän jälkeen päästään valmistamaan varsinaista kaarta ja kattoa näihin muotteihin. Ikinä en ole lasikuitutöitä tehnyt, joten katsotaan, mitä tästä tulee.

For various reasons I decided to replace the camper canvas with new approach. Bimini top and radar arc will be made from glassfiber, and for harbour uses, transparent camper sides can be added. While driving, bimini top is all I need.

Plugs

Phase 2

Starts from here... wood.

Closeup, still needs sanding

Lestejä piti hiukan korjata, jotta ne toimisivat muotin valmistuksessa. Jotta muotti ei jäisi lestiin kiinni, sen kaikki sivut pitäisi olla 5 asteen kaltevuudessa. On tässä yllättävän paljon puuhaa.

Plugs were having slight problems, so I needed to work more with them. Added narrow lists with 5 deg angle in order to get inner edges opening enough so that plug can be removed from mold. Quite much work in these... and the  challenging part, the roof top is still way ahead.





It looked like to be an impossible project, if the hard top should have been assembled on boat. Winds and sea will sometimes be harsh, so hard top needs to be as rigid as possible. I decided to make 1:1 mockup from our boat cockpit. Well, not the whole cockpit, but essential parts from it. When the replica cockpit is ready, it will be easy to start installing and laminating the hard top parts together. No worries about vinylester spills. And when the project will be ready, I just lift the hard top from this mockup and install it on the boat.

I was just today thinking, that there must be some nuts loose in my head, since I am still going on with this...

Kyllä, tästä tulee veneen ohjaamon takaosa. Ideana on, että koko katon voi rakentaa tähän ohjaamon laitojen päälle, ja voi rauhassa mallailla, hioa ja laminoida osia kiinni toisiinsa. Päätin valmistaa myös takatuet lasikuidusta, ja tästä tulee silloin hiukan eri näköinen kuin kuvassa ylhäällä.

First part under manufacturing will be the top itself. I will not make a plug from it first, so building now a mold for the top. Material cost for this size of reusable mold manufactured from glass fiber would be big, so I decided to make one off. You either take time to sand and polish plug and mold, or then you work on that amount of time with plywood mold and the part itself.

Mold manufacturing starts

Middle section attached with small screws 

Arcs are made from 15mm and 18mm spruce plywood, mold surface is 4mm birch plywood. Now mold structure is rigid, and it is easy to start manufacturing both ends of the mold. I cannot use these same arcs in those, since both ends of the top will be slanted, to have better shape and strength.

Plywood ready !

Painting, sanding and more putty...

While this surface starts to be better, next it is time to start manufacturing edges for the front and rear end of the mold.  Elikä etureunan ja takareunan kynnykset vielä paikalleen, ja sitten projektin voi viedä talvehtimaan.

Front edge

Structure of front edge

Rear edge

Rear edge is ready, but front edge still under construction. It is important to get front edge symmetrical, therefore structure is more complicated than in rear edge, where you can actually get symmetrical shape easier. With these edges the hard top will get more strength and shape. Also the inner edge of this roof will serve as a place where side curtain studs will be attached.

Front

Needed to turn the mold upside down, and reinforce middle part with fiberglass. Here you may already see, what will be the shape of the roof. Hopefully reinforcement will make this mold more rigid.

Back

Mold ready

I got couple of professionals involved in this project, and they said that straight side supports would not look good. So I decided to use router and took some wood off with 1mm slides from roof level to middle of the support. Then it has thickness of 50mm in bottom and 40mm in roof level.

Under routing

Next phase is edging and painting

Edge is made of 9mm birch plywood

Side support plugs are ready. When inner corners are now smoothened, you can now start seeing, how will the final parts be looking at. Cool! I am actually pretty happy for what I have achieved so far. Now it is time to wait for summer and higher temperatures for glass fiber works.

Laminating

Making the mold without a template from plywood was quite easy, but the problem was: how would the real piece look like when ready? Answer will be given shortly... I just hope my mold brings a good looking roof. I decided to leave this work for professionals. Quality of craftsmanship is secured.

The paint I had been using, Hempel Underwater Primer, was not a good surface for laminating. Therefore they needed to rework the surface with glassfiber and topcoat. Now it is a REAL mold. Looks very good !






Construction is sandwich. Between glass fiber there is Divinycell, and as you can see, not everywhere. Four places without Divinycell will be done from solid glass fiber, these are attaching spots for side pillars.

Divinycell core

Ready, set, go...

Hard Top separated from its mold. Nice!

Rear edge

Front edge

Shape

Hard Top - front edge

Building a lifting crane. Layer of top coat applied for side pillar plugs.

 

There are small wheels in crane, and lifting mechanism is 1:2. That is enough, since the weight of top is only 40kg.

Just because of one stupid paint selection at beginning...

Molds released from rear pillars

Since roof laminating guys noticed that original single component primer I had been using was not suitable surface for laminating, I decided also to do something about it. I applied topcoat on top of these plugs. But, maybe the wrong type of primer reacted with it, temperature was too low, amount of hardener too low, or layer of top coat too thin... topcoat never hardened. It hardened nicely in bucket, but not on plugs. I had nice plugs with soft surfaces..! And applying resin, didn't help either...

So I layered 30g/m2 sheet of fibreglass on top of plugs, then painted with Hempel blue 2-component light primer, finalized with two layers of Hempel black 2-component Polygloss polyurethane surface paint. Sanding. Lot of time just by waiting each layer to dry out.

Mold thickness is about 4 mm, so there is gelcoat, primary mat 100g/m2 and then 3 layers of 450g/m2 mats. Before laminating the plugs were waxed 5 times with Carnauba wax and then wiped with PVA mold releasing chemical.

In front, rear pillars under manufacturing.

Structure: 2 x Gelcoat, 2 x 300g/m2 mat, 20mm Divinycell, 2 x 450g/m2 mat.You will see 20mm Dinvinycell inside, creating strength for pillar. When pillar is separated, edges needs to be trimmed, attaching places for bolts and nuts strengthened, and finally the inner side of pillar will be laminated.

In rear, molds are just laminated on top of plugs. Structure: 2 x Gelcoat, 300g/m2 mat, 3 x 450g/m2 mat.

And going forward... next pictures!

Finally something, which looks outside like a final product!

Pretty soon also front pillars will be done.

I decided once again to use professional help. Front pillars are taking biggest amount of weight and stress of the roof. And even if I am pretty satisfied how I succeeded with rear pillars, I don't think I have skills enough to make first class lamination for these bigger pillars...

Front pillar attached to "boat"

Alignment with wooden block

Attachment with lamination

Front pillars became ready made from professionals, and finally we started putting pieces together.

Latest addition, radar arc. This will be installed on top of the roof for antennas and light.

First drawing the edges with tape

Lamination, divinycell for edges and lift off

Structure of arc divinycell

Mounting piece plugs for radar arc

How does it look when parts together:

Attachment with crane

Many layers inside

Radar arc placement

 


Hard top needs at least one week full work with details. Front pillars needs inner surfaces, radar arch its corners and attachment, edges of the roof needs to be trimmed better. Then it is ready for painting, and finally for installation. Summer is coming !

Project week

I hired a professional boat builder to help me with difficult jobs. I can use my talent for sanding and other assisting jobs.

Day 1

Making templates and plugs for side panel molds. Glueing PU plate for the edges. Plate edges were sanded with a specially made sanding tool.



Day 2

The roof was turned upside down, so we could start work on with edges and inner structures. Molds were laminated. Inner cable channel was glued in its place.

Day 3

Lamination of edges and inner arc (holding the cable channel inside). Trimming and waxing the molds, laying gelcoat on them. Laminating structural support for front pillars. Lots of sanding putty and sanding is needed before painting.





Day 4 and 5

Finalizing parts from molds, sanding the roof, attaching new parts into it. First installation of radar arc was done. Now it is in correct place and, but needs quite much work to fit seamlessly with front pillar lines. After this phase, surfaces needs to be smoothened, and painting can start.

Continues...

Bottom paint, sanded (silky smooth)

Painting after second bottom paint

They were saying they will paint it Ferrari red... but this fits better

How does it look when it is installed to boat ?

Here some pictures before and after... I still need to make some panel work, attach cables and lights end so on. Project was succesful. Good job guys! Made in Paraisten Venekeskus.

Before

After

Before

After

This is quite unique

Canvas ready