hard dodger front

[Chanquete]

Hy
Strolling along the marinas of the Nautical Club of Mar del Plata I found boats equipped with these interesting dodger fronts.
The windows seem to be composed of armored glass (as used in glassw windows of shops) which is undoubtedly mor scratch resistant than the usual flexible transparent plastic sheets.
The windows of the usual canvas dodgers are typically quite opaque.

It would be very valuable for me to hear opinions about this type of hard dodger fronts.

Thanks in advance

Chanquete

 

[ianabc]

Toughened glass
or
Laminated glass
or both

Which is "best" ?

 

[Chanquete]

Toughened glass
or
Laminated glass
or both

Which is "best" ?

Tempered glass also known as toughened glass is very strong and is regularly employed as safety glass. Tempered glass is known to be several times stronger than laminated glass. On the other hand laminated glass is normally used in windshields side and rear windows of automobiles. It is commonly more costly than tempered glass.

 

[john_morris_uk]

I thought that tempered glass shatters into thousands of tiny bits if it does break. Laminated glass cracks but the plastic film in between the two layers of glass holds the whole thing together. I would suspect that the glass in a fixed spray hood (which is how I would describe those pictures) would be laminated and not tempered.

 

[caerolusmagnus]

Lexan polycarbonate vs autoglass

I thought that tempered glass shatters into thousands of tiny bits if it does break. Laminated glass cracks but the plastic film in between the two layers of glass holds the whole thing together. I would suspect that the glass in a fixed spray hood (which is how I would describe those pictures) would be laminated and not tempered.

I am planning a rigid dodger/sprayhood. I have lexan polycarbonate in mind but see here the excellent site of Beth Leoanard and Evans Starzinger with their many free downloads; this link directs to the comments on polycarbonate vs tempered/laminated tinted autoglass

http://www.bethandevans.com/hawk.htm

 

[rogerthebodger]

When I built my current boat I had the each windows in my wheel/dog house made from 2 sheets of 6mm thick tempered/toughened glass then had then laminated together. This gives extra strength but if the glass does shatter the window is still kept intact so it will not allow water to enter. In fact I did have one window break during fitting and only one of the sheets of glass shattered the inner one remained intact.

I did consider polycarbonate but IMHO the surface is too soft and scratches too easy and with larger size of openings like I have the flex of the polycarbonate could cause the window to pop out if too much load is placed in the centre of the window.

 

[JumbleDuck]

Tempered glass also known as toughened glass is very strong and is regularly employed as safety glass. Tempered glass is known to be several times stronger than laminated glass.

I find that a little hard to believe. It's certainly more scratch resistant because of the internal stresses, but it's the same material and I'd be very surprised to find that the UTS is significantly different. Still, i could be wrong. Do you have a reference?

 

[rogerthebodger]

Its not Ultimate tensile strength its impact resistance that is much better. Not as high as poly carbonate but PC has other problems as noted in my previous post .

 

[Rigger Mortice]

I very much doubt that it is glass in those pictures.

Fitting glass with exposed edges, drilled holes and radiused corners like that would be a silly, and expensive, thing to do. To install glass on something like that a window rubber strip would be both better and cheaper.

My bet is that it is plastic.

 

[alahol2]

I very much doubt that it is glass in those pictures.

Fitting glass with exposed edges, drilled holes and radiused corners like that would be a silly, and expensive, thing to do. To install glass on something like that a window rubber strip would be both better and cheaper.

My bet is that it is plastic.

Agree. Acrylic or polycarbonate.

 

[rob2]

+1 The windows are screwed down onto mastic, a technique commonly used with either acrylic or polycarbonate sheet, but difficult with glass - especially toughened glass which would shatter if you tried to drill holes in it! Toughening is achieved by heating the finished component to its plastic temperature and then chilling the skin so that the skin solidifies. As the inside cools and contracts it holds the skin under tension so that should it break, the shock is transmitted throughout the component and it shatters into small granules rather than producing sharp shards.

I do like the design shown though, the rounded edges and "rounded" shape is much better than the slab-sided, brick outhouses I've seen in the UK.

Rob.

 

[davidej]

+1 The windows are screwed down onto mastic, a technique commonly used with either acrylic or polycarbonate sheet, but difficult with glass - especially toughened glass which would shatter if you tried to drill holes in it! Toughening is achieved by heating the finished component to its plastic temperature and then chilling the skin so that the skin solidifies. As the inside cools and contracts it holds the skin under tension so that should it break, the shock is transmitted throughout the component and it shatters into small granules rather than producing sharp shards.

I do like the design shown though, the rounded edges and "rounded" shape is much better than the slab-sided, brick outhouses I've seen in the UK.

Rob.

This seems to support my belief that glass can only be toughened/tempered after it has been cut to size, rounded, drilled. etc

This would be unrealistically expensive on a one-off basis

 

[Rigger Mortice]

+1 The windows are screwed down onto mastic, a technique commonly used with either acrylic or polycarbonate sheet, but difficult with glass - especially toughened glass which would shatter if you tried to drill holes in it!

True. If you want holes in toughened glass, you drill/cut them before the glass is toughened. It's not unusual; think shop doorways.

 

[causeway]

I'd love a hard dog house or at the least a fixed window type setup a la halbergs.

Has anyone ever managed to make a decent one on the cheap? I'd be interested in the details. With the price of a spray hood, it might be the better investment

 

[cmedsailor]

View attachment 42293View attachment 42294

Hy
Strolling along the marinas of the Nautical Club of Mar del Plata I found boats equipped with these interesting dodger fronts.
The windows seem to be composed of armored glass (as used in glassw windows of shops) which is undoubtedly mor scratch resistant than the usual flexible transparent plastic sheets.
The windows of the usual canvas dodgers are typically quite opaque.

It would be very valuable for me to hear opinions about this type of hard dodger fronts.

Thanks in advance

Chanquete

Hard dodgers are probably nice to have but the specific ones in the picture are too small. I mean they don't offer much protection (to the inside of the boat only been so small) from the hatch door.

 

[causeway]

Something like this with pop studs on the top for a cover would be great.


Dropping the boom on it, not so much.

 

[PlankWalker]

I find the frame structure intriguing.
How would you construct that? If in fibreglass would you need an internal and external mould.

 

[JumbleDuck]

This seems to support my belief that glass can only be toughened/tempered after it has been cut to size, rounded, drilled. etc

This would be unrealistically expensive on a one-off basis

Not at all. When I had the windows for my Hunter 490 rebuilt, it cost three pounds per window extra to have them done in toughened glass rather than perspex.

 

[PetiteFleur]

My friends Contessa 28 has a rigid front & side screens. Frame made of teak with glass, two at the front and one each side. Canvas top and sides with a stainless hoop for the rear grab bar. Seems to work fine. Sorry , no pics.

 

[Rigger Mortice]

I find the frame structure intriguing.
How would you construct that? If in fibreglass would you need an internal and external mould.

My guess would be a lay up in a female mould with mat finished of with cloth and/or tissue. Possibly with flowcoat to pretty it up.