Skylight Hatch / Dog Box

[BBB2015]

Hello there

I am a new member here so hello to start with!

I bought a secondhand boat about a year ago which had a flat skylight panel which inevitably leaked slightly where the glass sealed into the aluminum frame. I spent quite some time looking into a solution and after some consideration found a good solution which I would like to share with anyone who is interested.

I decided to have a dog box style hatch built out of steel. I thought it would probably involve less looking after than wood and as my window panes are quite large would support the glass better. My boat is quite modern and I thought a steel hatch would also suit it better. The hatch is 1.6m x 1m and this is what was built.

 

 

 

The hatches on either side are single glazed and I retained the original flat window panel for an extra layer of water tightness and a secondary glazing. There is a small air vent each end of the hatch to deal with any day to day condensation between the glazing and the hatches are bolted down so that they can be lifted for cleaning.

 

 

The inner hatch is bolted into a steel window aperture and the new outer dog box style hatch is screwed into the roof. This means that we can still remove the hatch and window should we need to lift large items out of the boat (albeit with a bit of hassle) and I have sealed the screw heads with paint. The result is attractive and 100% watertight and we are very pleased. The inner wood trim even matches the american oak in our lounge!

 

Here is the view from the inside:

 

I hope this helps anyone who is considering a solution to a similar problem as it took me a while to decide how to tackle this.

 

Martin at Kedian Engineering manufactured this. I had heard good things about him on the internet and he surpassed even my high standards.

 

Hope this is of interest to some fellow boaters.

 

 

 

[Martin Kedian]

WOW thank you for your kind words much appreciated so glad you are happy with it

It sure is a big one

[BBB2015]

You deserve it as it is a great design and an excellent product.

I meant to write up about it earlier but was having problems getting into my account and posting here.

Thanks again

[canals are us?]

Looks very nice and just the sort of design I would like.

 

One day I will get Kedian Engineering to make me a smaller version for my Liverpool trad narrowboat about 800mm long and around 600 wide but to use with double glazed units either open-able or not depending on the cost difference. I will then glaze them in 6.4mm laminated glass double glazed units.

 

Thinking this would let even more light in over the salon as I have smallish bus windows.

 

James

Edited May 27, 2015 by canals are us?

[pquinn]

Nice work.

[Martin Kedian]

I am sure some may be wondering about the cost fully installed as pictures gloss paint and 6.4 mm Laminated safety glass £1'400 .00

Double glazed units can be used instead of glass at cost

Regards Martin

Edited May 28, 2015 by Martin Kedian

[Mike Jordan]

The quality of the fabrication is obviously very good, I like the appearance and also the handle on each end of the box to assist in lifting it off.

The down side to the job is the need to line every bit of the internal steelwork to stop condensation forming on the inside faces.

I suggest that anyone considering this type of hatch should first talk to others who have used their boats with steel hatches or Houdini type roof lights through at least one winter. The truth is that they are a nightmare!

I have wasted a lot of time down the years trying to persuade new boaters who want to "lie in bed and see the stars" to talk to other boaters before having a hole cut in the roof.

I have also spent many hours (and made a living) from making internal glazed shutters and sliding inner hatches in attempts to solve the problems caused by these type of hatches. They are great for ventilation over the galley and in hot weather but near useless in a boat occupied during cold weather.

Hardwood boxes are much better from the insulation angle and in all instances double glazing with toughened and laminated glass is a must!

I think this post will be unpopular with some so don't take my word for it, talk to someone who has had one through a winter.

[BBB2015]

Mike I'm not sure if you read my post properly. The purpose of this exercise was not to look at the stars or for ventilation but to resolve a problem that was already in place when I bought the boat. The fact that you get extra light and a view of the sky is a bonus.

 

I already have a glazed window which is underneath the hatch and this is why I have decided it is not neccessary to line the steel hatch fully. The the hatch is already secondary glazed and there is also a blind which acts as an additional barrier from warm air reaching the glass when closed.

 

The hatch was installed in March and I have not experienced any condensation yet and I have a large aquarium on my boat. Should this happen in the winter then I intend to replace the internal glass window with a vacuum double glazed unit - thus triple glazing.

 

Of course there are important considerations when building something like this but I do not envisage condensation being a problem with this design.

[Mike Jordan]

Hi

You are quite right, I failed to read carefully and also missed the clues in the photos. Your solution is similar to one I have seen where a hardwood dog box was made to fit over an existing Houdini hatch to keep it a little warmer in the winter. It was only a partial success but better looking than the 200mm slab of polystyrene and a purpose made cover used on top of a Houdini by some live aboard friends in an attempt to sort the drips.

Some of the Dutch barge shells sold for self fit out come with a steel box similar to yours but without the inner hatch. Those I have met with these are sick of condensation long before the job is finished, and sometimes resort to replacing the steel hatch with a double glazed timber one. An expensive solution for a problem which is very predictable.

Mike.

[BBB2015]

Thanks Mike and this is why I took a long time to think carefully about this solution. There are many ways to tackle these things all with varying degrees of success. I even considered having some kind of tri-layer polycarbonate moulding made but thought this would look better (it does!).

 

The temporary solution used by myself and the previous owner was an inflatable dingy which was sitting covering the old single glazed hatch. That actually worked perfectly and was also a good insulator but was a bit unsightly to say the least!!

 

As prices have already been mentioned, for the sake of completeness I should say that should it be neccessary to change the internal window - a vacuum double glazed unit of these dimensions (1.6m x 1m) is around £200 but to be honest I don't think it will be required.

[canals are us?]

I have a pigeon box over my bed made of steel and 4 single glazed roundels. It used to drip in heavy rain and was very draughty in winter. The simple solution is to open the pigeon box and place a sheet of laminated glass on top of the roof lining frame, then close. Thus the glass catches the drips of condensation or drips in heavy rain and I don't get dripped on. Not used the glass this winter.

 

James

[Martin Kedian]

It is often the fact that bad design is the issue with water leaks in pigeon boxes but it is possible to build one that is watertight it just requires time and design skills

Regards Martin

[ditchcrawler]

I have a wooden dog bog and I put my MiFi on a small shelf in the top of it, this gets it outside the steel box for reception but inside to transmit to the computer.

[Cheshire cat]

I have a wooden pigeon box and that created condensation to some extent when we were sleeping under it in the winter. It wasn't noticeably dripping but needed a wipe down internally in the morning.