Building a hard top dodger to enhance your cruising

Our canvas bimini, dodger, clears and covers, although not the first to be installed on FriendShip II, had come near to the end of useful life after constant restitching and patching had became a common endeavour. It was time to either replace them on the existing stainless steel frame or look for alternatives. I found that most of the wear and tear occurred on the dodger and bimini tops as these were the most exposed to ultra-violet degradation. Canvas, particularly the stitching thread depending on quality, will only last around five to eight years in the sub-tropics.

Another issue I had with FriendShip II was reaching the high boom to repack the slabbed mainsail. I envied the catamaran skippers who simply walked atop their coachhouse trailing the boom bag zipper behind them!

Thirdly, my vision ahead was impaired as the dodger top was directly in my field of sight. Bending over to see through the clears while navigating out of Manly Harbour was neither safe for the on-coming vessels, or for my aging lower back.

Other benefits of a hard top dodger are the ability to integrate an additional cockpit light, grab rails and an extra set of stereo speakers, although I decided against the latter.

The negatives: extra weight up high and windage. However, the weight of my dodger is about half of the average crew member and most of the windage comes from the side clears, which can be easily removed if required.

The design

The decision was made to investigate materials and design. Having one made professionally was not an option due to the labour intensity, therefore cost, of a custom job. Research online proved more than helpful and, after careful thought, my design and build concept was put to paper:

  • it needed to be practical

  • hard wearing, strong, long lasting, with minimal maintenance

  • require clear vision from the helm

  • ability to climb aloft to pack the mainsail

  • light in weight.

Just as importantly as all of the above, it needs to be aesthetically pleasing, appearing integral to the original vessel design. I contemplated a hard top bimini as well but could not visualise this to be anything but ugly on my vessel, so decided against it.

The dodger also needed to be something I could build myself, as a semi-competent handyman.

How big to make it is an important decision as this will determine how it will look after installation and how effective it will be for shade, ergonomics, etc. I wanted mine slightly smaller than the cockpit coaming, which runs around the entire Hunter 450 centre cockpit like a big bath tub. When the ply is bent to shape, it will decrease slightly in width. This will provide a little bit of rake off vertical when the clears are added. So, the pattern was to be the same size as the outside measurement of the coaming.

I used a large piece of cardboard laid over the coaming which I traced out, then cut. It is a good idea to place this cardboard cut-out above the cockpit in the intended position, to see how it will look once the dodger is built. It will also help establish where the stainless steel struts will need to be positioned and if there is access below deck to secure the bolts. Once happy, I then transferred this measurement to the marine ply.

Materials

Having limited experience in working with fibreglass, I used the advice of my local suppliers and decided on a six millimetre marine plywood core with a polyester fibreglass outer shell.

Although the 6mm ply is lighter, you may want to use 9mm for the extra strength, depending how large and how curved your dodger will be. I would also spend the extra money on either vinylester or epoxy resin should I do this again.

I also used a polyurethane foam from which I shaped a rain lip around the front and side edges of the dodger. On completion, the clears will be attached to the inside edge of this rain lip with sail track, providing a seamless appearance from both inside and out.

Framework

Having cut the ply to the required shape and rounding any sharp edges that will be glassed over, it is time to build a cradle on which the ply will be attached to give the dodger its curved, or arched appearance.

I wanted a 100mm curve from the centre to the sides.

This will allow the water to run off well and give it a nice nautical look.

For the cradle, I used two lengths of cheap custom board and cut one long edge of each with the prescribed curve where the ply will be attached. Three or four shorter boards are screwed to the inside of each custom board length to box the cradle. The cradle needs to be approximately 2/3 the total width of the ply. Small blocks of timber are screwed about every 250mm to the top outside of each curved edge; this is where the ply will be secured to maintain the shape once bent.

If a very pronounced bend is desired, or the ply is very thick, steaming the plywood is necessary but was not required for this job.

Starting the build

Marking the centre of both the cradle and the plywood on front and back, I aligned them on each piece before drilling 316 stainless steel screws through the ply, securing it to the small blocks attached to the cradle. I decided that the 6mm ply might flex too much to walk on, so glued and screwed some timber stringers along the dodger to add extra strength and rigidity.

For the rear of the dodger I glued a strip of half dowel to both the top and bottom edges. This provided a nice curve for glassing over and a smaller rear rain lip.

The next step involved spreading a hot resin mix over the underside, which is actually the ‘working’ or top side of the dodger secured in the cradle. This will soak into and seal the plywood prior to fibreglassing. For this I used a mix of resin and ten per cent hardener, then adding an equal amount of thinner to the mix, applying quickly by brush.

I cut and glued 15mm x 40mm strips of polyurethane foam around the front and side edges of the ply; shaping and cutting relief slits as required on corners to allow bending of the foam. I then repeated this process over the top of the previous layer, obtruding outwards. Do not use polystyrene foam for this application as it will melt when resined.

Once four layers of foam were applied, it was time to shape the lip. I applied more layers of foam than required, as this needs to be trimmed back at a later stage. All relief slits were filled as described below, so no air gaps remained. Using a hacksaw blade and utility knife I cut the desired angle on the inside and outside edges of the foam, then carefully sanded the foam with 240 grit sandpaper to get the desired consistency of shape.

The final step before glassing is to apply a filler compound to all sharp angles and sand fair. I used resin, hardener and talcum powder, mixed to a toothpaste consistency and applied to areas such as the rear lip, foam lip and stringers. I made a rounded spatula out of an ice cream container to get the shape required to apply the compound to the inside corners of the foam lip, providing a nice curved surface for glassing over.

Time for glassing

I used one layer of chopped strand, then a layer of glass mat over the entire underside and up the sides of the foam rain lip using accepted fibreglass laying techniques. Do not forget to wear your personal protective equipment, particularly when sanding.

After this has hardened, it is time to remove the dodger from the cradle. To do this I simply unscrewed the timber blocks from the cradle that are secured to the dodger. I expected the bended ply to straighten slightly, but to my delight, it held shape quite nicely.

Time to flip the dodger over and work on the top side.

The timber blocks needed to be removed, the remaining screw threads ground off and filler applied to the holes left behind. Then another hot mix and repeat glassing as on the underside.

Looking like a dodger top!

Now that the final product was coming together, it was time to cut and fill the foam lip that had been glassed over on each edge. I measured and drew a line with a permanent marker where the lip would finish and used a saber saw to trim off the unwanted length. The rough cut needed to be sanded; I used a portable belt sander, but an orbital sander or a file would suffice, if not take a while longer.

The foam, now inside the fibreglass sandwich, then needed to be gouged out a little, around 10mm to 20mm, then a filler applied and shaped to give the desired rounded edge to the lip. Again, I cut out an old ice cream container as a curved spatula to shape the filler for this task.

Dry fitting

Now was a good time to take the dodger back to the boat to see how well it would fit and final look.

If, like me, you cannot weld, it would also be a good time to invite your favourite stainless steel fabricator to do the preliminary measurements and quotation for the struts, grab rails, etc.

I stood behind the helm to ensure it was in the proper position for vision underneath. I also checked the vessel from a distance to see how it would look.

This is the time I decided to lower it so I would look over the top of the dodger from the helm position. I was hoping for a dodger I could walk upright underneath and see under from the helm, but the profile view did not look right and changed the visual appeal of the vessel, so a lower profile was decided upon.

Fairing and painting

Sanding, sanding and more sanding is the key to the best result. I applied three light coats of fairing compound consisting of resin, hardener and Q-cell, sanding in between coats.

Once happy with the finish, I primed then painted three coats of two-pack polyurethane on each side. I sprayed the underside for a nice gleam and rolled the topside with a textured roller to provide grip for walking aloft. This might wear more quickly than using a grit in the paint such as ground walnut shell or sand, but it is holding up so far and provides sufficient grip under foot.

Final fitting

It was time to wrap the finished product in an old doona, tape it up and freight it carefully to the boat, scratch free.

Using webbing straps around the dodger top, attached to the mainsail halyard, I lifted it to the desired height above deck. A spirit level assisted in ensuring it had a slightly forward pitch and I measured both sides and forward and rear edges before securing it with as many tethers as would allow, so it would not move out of alignment.

It was time for the welder to fabricate the struts. I also had him make an under-ceiling brace for more weight capacity and overhead grab rails for moving around the deck.

Another feature added was a fold-out step on the rear starboard strut to assist in climbing aloft.

After the struts were in place and bolt holes drilled for the stainless steel plates, I raised the dodger and redrilled the bolt holes another 5mm in radius and applied an epoxy filler before redrilling the holes to the reduced size of the bolts. This provided a buffer in case of water ingress through the fittings so that it would not dampen and eventually damage
the plywood core.

The required result?

Having completed making and fitting the surrounding covers and clears, I am more than happy with what I have decided upon. The hard-top dodger can support my weight and makes stowing the mainsail much easier; hence I am more willing to deploy the sail, even when the wind is light or on a short downwind run since I know that packing it away is not so much of a chore.

The quality is probably not what I would consider professional, but it is appealing, looks purpose-built and is strong and sturdy.

My crew and guests have more assurance walking out of the cockpit and around the deck with the added grab-rails.

I now have more light in the cockpit with the integrated LED light fitted above the cockpit table.

I do not have any concerns that I will need to replace the dodger anytime soon. Perhaps a coat of paint in a few years.

Would I do it again?

Definitely. It may not be needed again on FriendShip II but, should I change vessels, I would certainly consider a hard top dodger.

For those considering doing this, make sure you have plenty of time up your sleeve, it is a more time-consuming job than first appears!

Peter Lewis
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