First, if the dodger
is for a 27 foot boat as in your profile then you will likely find it impossible to build a useful one that gives access to the companionway
but doesn't look like a skyscraper. It is very difficult (and those with a concern for aethetics would say impossible) to build a good looking hard dodger that fits the profile appearance of the boat well and still give reasonable access via the companionway
in a boat much under 40 foot. At 40 foot you still need quite a deep cockpit
to do so which translates into higher freeboard if you don't want the floor of the cockpit
regularly backflooding through the drains.
In our own case the dodger was built by the yard who built the boat for us and this for a dodger which we wanted to be able to support a person walking on it as well as solar panels
- so I did not build it myself. Among other materials the yard was very experienced building in fibreglass and composites including advanced ones such as kevlar and carbon. Out of their experience across those materials they chose, for a one off, to build it of plywood
and then fibreglassing that inside and out. That saved the building of a mould and the heavy fairing needed on the at least one rough side if out of a mould.
To get the curve on the roof to get side fall they laminated several thicknesses of ply bent over a temporary form. The window cutouts were rebated out around the edges and the toughened glass windows glued into those with Sikaflex 295UV. If intending sailing in areas of high solar
flux then would recommend using a high performance (tinted) glass but that incurs higher cost. A flange out of glassed ply (about 1/4 inch thick from memory) is around the bottom edge of the dodger and the whole through bolted with machine screws right through the deck
The whole was then sanded to give rounded outer corners, glassed over inside and out and coved in the inside corners and faired with bog, epoxy
undercoated and top coated inside and out with linear polyurethane
. A useful thing often not seen on dodgers is across the aft edge of the top there should be a raised piece right across so as water
on the top from light spray or rain does not dribble down off the aft edge into the cockpit - it also gives a bit of a finger grip when standing behind the dodger and looking for support. In our case that is about 3/4 inch high (from memory) from shaped timber and coved to the top with bog.
A problem exists if one needs to bring lines back into the cockpit through the front of the dodger (eg for vang, mainsheet, single
line reefing, etc) in that the penetrations let water
through. In our case we midsheeted the boom so the mainsheet track runs across a little in front of the dodger. It is raised on a solid base which then forms a wave break - even though penetrations are still required through this for the same lines it does do a lot to prevent water through the line penetrations in the front of the dodger.
Ours is quite similar to this one Picasa Web Albums - Steve - Hard dodgers ...
but is a bit lower (able to do so as we have a deep cockpit) and a little longer so giving a bit more cover in the cockpit. That link also shows the mainsheet track raised across in front as we did but in our case the track runs pretty much the full width of the dodger so longer than that shown.
Of course, much simpler structures can be made if don't need to support a person walking on them.