Suggestions for Hard Dodger Construction Please

[Cheechako]

Originally Posted by 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

Yeah, standing headroom when you are one step down the ladder maybe....

[Snowpetrel]

I built mine from plywood. Two layers of 6mm on top and one of nine, doubled in between the windows. Much easier to build and fair than a foam and glass one a freind had built earlier.

Lower is better for looks and I never really worried about the lack of headroom on my smaller boat, but I did have a perspex dome in the middle that I could stand under and look out without getting wet. The next dodger I build I am thinking of trying a raised part like a small dodger just over the walkspace. Hopefully this will get me headroom and a low profile, with visibility forward from the cockpit over the dodger.

Looking at your design, try lowering the front but keeping the back higher. On most yachts they look best this way rather than level (or droopy aft which IMHO looks terrible on yachts but suits some workboats) and it gives more headroom where its needed. Make sure your sightlines forward from the helm are not totally screwed up by the dodger.

Keen to see what you come up with. Cheers

[DennisDW]

Thanks Everyone for the great suggestions and kind comments. I'll take 'em!

I plan on building it then modifying it by cutting off the bottom edge. It will fit better on deck as that will bring in the angled panels a bit and will compensate, to some degree for the fact that my mold/mock up doesn't allow for the finished product's thickness. I'll do so slowly. First I think I will cut 2" off the front, angled back to the rear to see how it looks with the top lower in front. If I like that and the fitment to the deck is OK I'll lower it another two inches over all and check for looks and fit. I can go 6" and still stand under it and of course I definitely don't have to stand under it. I can go lower as needed. Some how I think the 6" figure is just about right.

I will play with the aft edge design on paper. I had thought of canvas side curtains. Many dodgers have spray curtains like that. I had also thought about a hinged cut out for the winch handle clearance or maybe even a sliding panel like a pocket door.

This weekend I'll attach the foam to the top, trim it and glass the top side. Next I will remove it and remove the door skin top. I'll fit the foam side panels and probably glass them next week end with the top back in place.

Two questions please, Should I use epoxy paste to glue the foam bottom of the top to the foam edges of the side panels or just place it and start glassing? Next, how in the heck to I keep the polyester resin from curing too fast to work in the hot Florida sun? It's 92 degrees and in the direct sun, much higher.
Yours,
Dennis

[Terra Nova]

Keep your materials out of direct sunlight. Erect a sunshade over your work area. You can even refrigerate or ice the chemical components.

Don't build any part of it to interfere with normal sailing functions.

[Cheechako]

One additional comment regarding height. Make the height so it's easy to see over when standing at the wheel. Trying to look through when docking etc is not always that easy.

[OceanSeaSpray]

Originally Posted by DennisDW

Two questions please, Should I use epoxy paste to glue the foam bottom of the top to the foam edges of the side panels or just place it and start glassing? Next, how in the heck to I keep the polyester resin from curing too fast to work in the hot Florida sun? It's 92 degrees and in the direct sun, much higher.
Yours,
Dennis

Dennis,

Stay well away from epoxy unless you do the entire job with it. This is because polyester doesn't bond to cured epoxy and any contamination on the foam will cause you grief afterwards. Just add glue powder to some polyester resin and use this to glue your edges.
You should glue all your edges first. If you have dead-flat panels, you can even opt to glass those on a table first, both sides. It is a lot faster and tidier than glassing at funny angles when you can avoid it and then you just glass the seams in place.
Once all your edges are bonded, you can sand a radius into them before glassing.

With polyester resin, you control the cure rate with the amount of catalyst, it is not a fixed, set ratio like with epoxy. In hot temperatures, it is extremely sensitive to catalyst ratio, so measure precisely what you are doing, don't mix too much at a time, keep it in a flat tray, not a pot, in the shade etc. Worst case, put water and ice around it. Start with a little trial rather than a large panel.

You need to shade the job until the resin has cured, or glass near the end of the day etc. If you bake the wet laminate in the sun, it will probably cause gas bubbles to form and ruin the job. Don't forget to wet your foam first and give it 10 minutes. If this starts curing, it doesn't matter. Add more resin and lay your pre-cut glass cloth after.

Eric

[NRosenthal]

[/IMG][/IMG]
Plywood stich and glue glass epoxy removable

[DennisDW]

Thanks Eric for the glass instructions. I did wonder about the catalyst ratio affecting cure rates.

Thank you NRosenthal for that photo. Based on that, my own observations and everyone's suggestions, I believe I'll build another mock up. I will make it lower, the center window wider, the intermediate windows angled aft along the deck less, the side panels longer and the roof sloped forward a bit. I think a few minor tweaks will make a big difference overall.

Door skin is $9.00 a sheet and 3/4" divinyl foam is $170. Cheaper to mock than to modify. I'll put up photos of the result.

CF is great for crowd sourced advice!
Cheers,
Dennis

[Nicholson58]

I mentioned my favorite resin near the beginning of this thread. US Composites 635 THIN epoxy. It is a very slow cure, no blush resin designed for maximum wet out of your fiber. I used it with 3M microballoons to cast 6 inch thick sections in our rudder. Basement work time is about 6 hours and cure time to sand is 4 days. It is soap & water clean-up prior to reaction and the easiest and least expensive epoxy I have ever used. I no longer use anything else. Buy it in 3-gallon kits & get the pumps. Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc.

[Terra Nova]

58--I've never tried that epoxy. The extremely slow cure rate may be more than useful for some applications. So I am interested.

My own experience with WEST system began in the '70's, and I've never found the need to switch. You know, once you find something that always works for you, and are setup with the pumps... I can't see the need for such extended cure times, for this dodger, as it is simple enough to keep the sun off the work and materials. So I would do this using the WEST system. Though I would use the extra-slow catalyst because of the high ambient temp.

I don't think there's a better product. Though I would try your recommendation, on any project requiring such a long cure time.

With the normal cure times, many coats can be applied in one day, eliminating a lot of sanding and preparation. Also glue joints made with WEST become strong within hours, so further fabrication progress can be made.

[Nicholson58]

Originally Posted by Terra Nova

58--I've never tried that epoxy. The extremely slow cure rate may be more than useful for some applications. So I am interested.

My own experience with WEST system began in the '70's, and I've never found the need to switch. You know, once you find something that always works for you, and are setup with the pumps... I can't see the need for such extended cure times, for this dodger, as it is simple enough to keep the sun off the work and materials. So I would do this using the WEST system. Though I would use the extra-slow catalyst because of the high ambient temp.

I don't think there's a better product. Though I would try your recommendation, on any project requiring such a long cure time.

With the normal cure times, many coats can be applied in one day, eliminating a lot of sanding and preparation. Also glue joints made with WEST become strong within hours, so further fabrication progress can be made.

We$t is not a no-blush epoxy. subsequent coats may not be as well bonded as you think. I have used many name brand epoxies and will never switch back. The ease of 635 THIN is far ahead of all others. It is primarily sold for large lay-up & construction. If you are vacuum bagging it is the best.

I have several photos showing wet deck re-core and rudder construction using this resin. Member Galleries - Cruisers & Sailing Photo Gallery For large open wet lay up i place the glass (or carbon) and use a throw-away brush to apply the epoxy. Paint the surface generously first. Apply the cloth and apply more resin with the brush. Use th brush to force out air & smooth the cloth. If you want a smooth surface or if you need to hold on a vertical or inclined surface, apply polyethylene sheet to the surface and the mats & resin will stay put.

[Terra Nova]

Yes, a very large vacuum-bagged project would seem the ideal application for that slow cure resin.

[Voyager269]

Very interesting thread, as we like to make a dog house on our Dufour 35.

As someone mentioned: we made a sketch over pictures of our sailboat. And i have made a drawing scale 1:10.

Very good suggestions about using foam and making a hatch on top!!

Please show us more photos if you can!

Taco.

[Roy M]

Here's a nice combination, along the lines of what I'm about to start:http://www.cruisersforum.com/forums/...p;d=1403867402

[DennisDW]

Here' mock up #2. It's only 6" lower but to my eye it looks way lower. I think changing the aspect ratio of the panels did that. The roof line is angled down a bit in front. Not much, ½" per foot but it's noticeable.

There are two treatments to the aft edge of the side panels. The first straight line models the forward slope of the fixed ports, the transom, the deck details. The curved line has no bearing to anything else but relieves the hard angles.

I'm not content with the roof shape. It looks like a stove pipe cap with the overhangs.

Comments and suggestions Friends?