Suggestions for Hard Dodger Construction Please

[Emmalina]

We used honeycomb polypropalyne for a hard roof Very light and cheap and it sure isn,t going to rot. Just covered it in 2 layers of woven matting with epoxy on both sides.

[Jim Cate]

Or you could do what all too many DIY (and professional) builders seem to do:

In the dark of night, find an isolated telephone booth. Steal it, and take it to the boat shed. Saw it in half. Mount the upper half on your boat with a few screws. Done... and it even has a place to make phone calls!

Or at least many of the hard dodgers that we see look as if this is how they came to be!

Jim

[Saltyhog]

Originally Posted by Jim Cate

Or you could do what all too many DIY (and professional) builders seem to do:

In the dark of night, find an isolated telephone booth. Steal it, and take it to the boat shed. Saw it in half. Mount the upper half on your boat with a few screws. Done... and it even has a place to make phone calls!

Or at least many of the hard dodgers that we see look as if this is how they came to be!

Jim

Very true. I've seen some real monstrosities. Fortunately, in most cases they were appended to boats which I thought were ugly to begin with, so nothing lost. The crying shame is seeing a "phone booth" scabbed over the cockpit of an otherwise classic and beautiful yacht. There's an NA shedding tears somewhere. Artfully adding a hardtop takes vision and skill. At best, it detracts only a little from the lines of the boat. Just my opinion FWIW.

[Terra Nova]

Originally Posted by Saltyhog

...Artfully adding a hardtop takes vision and skill. At best, it detracts only a little from the lines of the boat...

Well said. There are many more ways to get it wrong than to get it right.

[DennisDW]

Thanks for the specifics OceanSeaSpray. I hadn't thought of bending foam around a frame but that certainly would be easy. I could build a frame inside the door skin mock up, allowing for thickness differential. The deck of the boat is divinyl core and has had areas saturated by water intrusion with no apparent ill effects. I'll go with your method. Do you think 1/4" is too thin for the foam? Thanks also for the material and layup schedule. That is just what I needed.

I also heartily agree with the ill looks of a clapped on abomination. I admit I was thinking, briefly, about splitting a galvanized trash can in half and 5200'ing a window in between the halves for a high class glass and platinum look.

Most offshore boats have canvas dodgers which look OK. I wonder why hard dodgers are so often boxy and incongruous? The flat panel sections? the height unrelieved by compound curves? Are we just used to seeing canvas dodgers?

Cheers,
Dennis

[Terra Nova]

Originally Posted by OceanSeaSpray

...I would use Divinycell foam core, 20mm thick in H60 grade (60kg/m^3)...
I have designed boats with this material and I have used a lot of it in the workshop as well...
For a one-off hard dodger, you should be able to make a timber framework and "bend" the foam panels on it, rather than making moulds. Tie them through with plastic cable ties or similar, glue all your edges, sand them round once everything is set and glass the outside first.
After that, it will be dimensionally stable and you should be able to cut the cable ties flush, remove the mould and glass the inside.

I would do it in E-Glass/polyester as there is no benefit in using more expensive resins for something like this. Three layers of 450GSM woven roving and as little CSM as possible should give you a strong and light structure...

Have you tried building a hard dodger this way? Did you have to heat the foam to get it to bend?

[travellerw]

Originally Posted by Terra Nova

Have you tried building a hard dodger this way? Did you have to heat the foam to get it to bend?

I actually have plans for a small dinghy that is built this way. I talked withe people who built it and they said you only need to use heat if you are doing a deep curve. The form will curve around gentle curves easily.

My plans called for copper wire, but everyone suggested zip ties as they are wider and less likely to pull through the foam.

I'm guessing a dodger would have a very gentle curve and this method would work awesome.

Here is a website with photos that shows the technique very well.
Attaching the Foam

[OceanSeaSpray]

I have been involved in building whole hulls I had designed this way (37' on a framed plug mould) and the whole interior of my sloop (which has no dodger incidentally!) is built out of this material. You normally don't need to heat the foam for "hull-type curves", but leaving it out in the sun makes a big difference compared to a cold winter day in the shed for example when curves are getting tighter, like around the base of the stem. Grades above H60 become stiffer as you would expect.

Cable ties are a good way of holding the foam down, the other is using those "plastic push-in nails" that look like Christmas trees, with barbs. Later you cut them from inside with a hacksaw blade.

1/4'' foam would hardly be effective, all the strength comes from the separation distance between the skins. The work is exactly the same, so for a few dollars extra you can make it immensely strong. 5/8'' would be ok, 3/4'' even better. Thicker foam panels bend more evenly on a framed mould too and you can sand down a nicer radius on the corners. I would use 3/4'' = 20mm.
It is a very friendly way of building and it leaves very little scrap, because you can glue a few offcuts together and turn them into a bigger piece again, especially for flat panels.

I don't know if canvas dodgers really look much better! It is hard to get these things to look ok on small boats, the elevations seem to sort themselves out around the 60' LOA mark.
I quite like this idea of splitting a trash can instead. I would make sure it has little round windows with the domed nuts showing all around to get that required retro submarine look.

[Nicholson58]

Originally Posted by Jim Cate

Or you could do what all too many DIY (and professional) builders seem to do:

In the dark of night, find an isolated telephone booth. Steal it, and take it to the boat shed. Saw it in half. Mount the upper half on your boat with a few screws. Done... and it even has a place to make phone calls!

Or at least many of the hard dodgers that we see look as if this is how they came to be!

Jim

that explains this beauty I saw on the lake today.

[DennisDW]

I've found a phone booth! By pure dumb luck it fits on deck and has a rotary dial goes round and round, click, click, click.

My door skin mock up leaves me nonplussed. It's too tall, which I will remedy by cutting of 6 inches from the bottom. The aft edge of the side panels needs to slope forward but because of the winch position, it cannot. I'm hopeful I can shape the windows to relieve the lines to some degree. Any suggestions. Not a match and kerosine. I'm not allowed to play with fire.
Dennis

[Terra Nova]

Originally Posted by DennisDW

...It's too tall, which I will remedy by cutting of 6 inches from the bottom...

You'll have to cut that 6" off the top as the bottom will no longer fit the boat. The basic lines look OK.

What I did on one of mine was to make the aft-most element an aft-leaning arch of 1.5" polished stainless tubing. This gets the aft edge away from the winches.

BTW, both the Alajuela 38 and Cambria 44/(46) are two of my favorite boats. David Walters is great.

[JPA Cate]

DennisDW:

We had a hard dodger built to Jim's drawings in NZ. It was cold molded, and came out well. It was 2" lower than the fabric dodger had been, and looked good. We had wires in it for outdoor speakers and for lights; but the best feature was the hatch we had in the top, to introduce airflow.

Try again with your design, I'm sure you can make something that harmonizes with your boat's lines.

Ann

[Jim Cate]

Everyone has their own priorities, but IMO the most common mistake in hard dodger design (and some soft dodgers as well) is the idea that you need standing headroom under its cover. I don't think that this is really necessary, and without that extra height the looks can be much less telephone-boothy.

Some Van de Stadt designs have integral hard dodgers that look great (IMO) and DO have standing head room. They get this by dropping the cockpit sole in the dodger area... something one can do if designing in from the beginning. But I don't like this either! It brings issues of water getting below decks more readily in a pooping situation along with the extra headroom, and to me the tradeoff isn't a good one. I hate it when that happens!

Boats are a floating collection of compromises!

Jim

[Terra Nova]

Jim--good post.

Generally, standing headroom is reserved for larger vessels. And, if the bottoms of your windows are low enough to easily see out, when seated, they appear very tall if they are high enough to easily see out, when standing.

A hard dodger will better suit the boat's lines if you try to do no more than you would with a soft dodger; looks better to not make an entire stern room out of it. A combination of the two works better than expected, for example, soft partial side curtains, particularly in the way of winch handles.

[Doug Brown]

Wooden mockups are great as you can get everything to "look right". We painted in windows to see how they would look. Eventually we made one out of 1/4" 5052 aluminum with safety glass windows and a modified Lewmar hatch as our opening forward window. Stronger than a tank, but heavy as one too (160-lbs).

The "foam core" method would probably work very well and be much lighter. If I had to do it all over again, I would either try foam or go down to 1/8" aluminum and plastic windows.

Doug