Suggestions for Hard Dodger Construction Please

[chouliha]

Hi Dennis

We built a hard top dodger many years ago before departing the US. Using a plywood form we used 3sheets of bendy ply epoxied together to create a mold. Then transferred to the garage where we used sheets of dyvincel as the core followed by 1 layer of biaxial cloth on each side. Total weight is about 12-13 lbs.

I will attempt to add a couple completed pics and if you want to see the sequence of build pics let me know.

regards

Chuck
Jacaranda

[chouliha]

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 first tried using thicker dyvincel. 3/4" .The shop I purchased from in SD said oh just heat it and then it will easily bend to match the mold. What I later learned is it was impossible for a DYI'r to do that. What I had was a heat gun. Like a laurel and hardy movie I would heat one end and by the time I got to the other side the heated end had cooled off. Would have made a great you tube video! what they use in the composite airplane industry is large ovens and slide the sheets into that. So I went back tail between my legs and purchased 3 pieces of. 1/4" dyvincel.

Ahhhh the learning curve. Ya gotta love it



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[minaret]

Originally Posted by chouliha

I first tried using thicker dyvincel. 3/4" .The shop I purchased from in SD said oh just heat it and then it will easily bend to match the mold. What I later learned is it was impossible for a DYI'r to do that. What I had was a heat gun. Like a laurel and hardy movie I would heat one end and by the time I got to the other side the heated end had cooled off. Would have made a great you tube video! what they use in the composite airplane industry is large ovens and slide the sheets into that. So I went back tail between my legs and purchased 3 pieces of. 1/4" dyvincel.

Ahhhh the learning curve. Ya gotta love it



Sent from my iPad using Cruisers Sailing Forum

Just kerf it on a table saw, or even with a circ saw in a pinch. Thin kerf blade for not too much camber, regular blade with closer together kerfs for extreme curves.

[JPA Cate]

Originally Posted by chouliha

I first tried using thicker dyvincel. 3/4" .The shop I purchased from in SD said oh just heat it and then it will easily bend to match the mold. What I later learned is it was impossible for a DYI'r to do that. What I had was a heat gun. Like a laurel and hardy movie I would heat one end and by the time I got to the other side the heated end had cooled off. Would have made a great you tube video! what they use in the composite airplane industry is large ovens and slide the sheets into that. So I went back tail between my legs and purchased 3 pieces of. 1/4" dyvincel.

Ahhhh the learning curve. Ya gotta love it



Sent from my iPad using Cruisers Sailing Forum

Chuck, that came out great! I like that all the "windows" are removable for the hot climes and ventilation, but can be in place for the colder climes farther south.

Ann

[Jim Cate]

G'Day Chuck,

Like Ann, I think that your dodger looks great! But some queries:

What holds it up?

Can you stand on it?

And, what did you use for glazing?

Cheers,

Jim

[IslandHopper]

Originally Posted by Jim Cate

G'Day Chuck,

Like Ann, I think that your dodger looks great! But some queries:

What holds it up?

Can you stand on it?

And, what did you use for glazing?

Cheers,

Jim

Not suggesting this is the same as Chuck's but here's a boat a few slips down from mine with a similar dodger, it has S/S tubing for the frame with a hard top and removable clears all-round, it's more like a hard top than a full hard dodger, very nice set-up.....

[Snowpetrel]

Hi Denis, dodgers are so subjective.. you are a brave man bringing it up on a forum, Beauty is in the eye of the beholder, and never ever criticize another man's dodger.

That being said I kind of liked dodger version two (#2) rather than three (#3). I don't like overhangs on modern yachts, so that part of #3 I do like, though the edges need to be rolled to soften them. Both versions look much better than #1 and I am sure whatever you do it will now look OK, but dont give up on the prototyping yet, you got to know the thing is perfect, otherwise it will always bug the hell outta you.

For what its worth, I would rather shift the winches aft to near the helmsman and keep the dodger simple and uncompromised and the area near it for sitting and relaxing. Better all round and easier shorthanded sailing.

I think the straight edge looks better, but you can curve the top edge aft and flow it into the curve of the top to give a great flowing look, hard to describe but this picture might help and this one

This is the dad version of my dodger. It has a pretty good genetic link, as I used the patterns from it to make Snowpetrels dodger.

Sloping the front more will help it look slicker, probably I would try to match the angle of the large cabin ports. Maybe cut into the top, and also raise the base so it has a flat portion butting up to the traveller. As you slope the front back you need to angle the sides in to stop a weird trapezoid window shape happening. I also like all the forward windows to be a similar size, and wider than they are high.

A rain and spray trap at the aft edge is essential to stop water being blown back and dripping of the back and down your neck. It also makes a great handhold and stiffens the rear edge.

Dodgers need to look light but strong, if the windows are two big like the halburg ratsy it can look flimsy. Thats why the Van de Stat ones look right, the strong beam at the back balances all the glass and it looks right.

You can see more PICs of Snowpetrels Dodger here Snowpetrel Sailing: A High Latitude Dodger.

All the best with the design and I am sure you will come up with something that looks great.

Cheers

Ben

[chouliha]

Snow Petrel Stunning job! It looks like it belongs! Kudo's

Jim & Ann - Greetings from Ecuador.

The windows are Strataglass, The canvas is Stamoid sewn with Goretex thread. There is also clear drop windows that cover the aft side so one can sit inside yet see out. Its protection from the elements but not like Snow Petrels design.

The dodger is fastened / thru bolted from the fwd edge of the handrails to a 1 1/4" SS tube that is bolted thru the cabin top.

The aft edge of the dodger is hung from tabs that run off the aft grab rail. Plus its thru bolts to the aft side of the handrails.

Rock solid and you can jump on it without it moving.

[Zach]

Something that works quite well with 3/4 divinycell on large diameter curves is to fiberglass one with mat, then torture it into place with ratchet straps and screw through down through the foam into the framing under it. Putty the screw holes as you are laying the top layer of fiberglass...

Fiberglassing one side makes it self fairing, self supporting over the frame work. Saves a lot of fairing work down the line too.

After the fiberglass is done on the top side, yank the framing loose from the inside, flip it over and fiberglass it.

To layout the top surface in a more pleasing way:

Athwartship the boat, loft the roofline on deck beams. Loft radius of the deck beams in three sections, the master radius done off a string and a nail through the middle third and then a spline sweep that drops the outer corners an extra inch or inch and a half a half or so at the outer corners.

From the stern she looks like a continuous curve following the radius in the center radius aft and is chalk line straight fore and aft.

From the side the height is played down at the corner level that extra inch and a half or so and it doesn't look nearly as tall, because the radius viewed from the quarter is not tall enough to gain as much height as it has. So your eye just sees the radius that is easiest to see, and not the arch that is really there.

A fir batten won't bend to it, but a plastic spline will... Connect the middle third of the fir batten line, and play the outsides together so the last 6 inches or so is a dead flat line. When you curve the roofline aft a foot or so aft, the center section is still has a sweet fair line, and everything looks "right" because you've lofted a parabola and the curve is getting farther away and your eye sees it as a radius on something that is tilting down by the bow. This is doubly true if you play the radius in the roof heading back to the helm, to play out with a complimentary tuck at the corners. A batten line that tucks down without drooping looks better than one that tucks up, almost always. Anything that runs even, or almost uphill starts looking like a duck bill or baseball cap instead of something that grew there in nature.

For the intersection at the front, loft the front face smooth with a fir batten and leave it round. Set the bevel the front corners in a few degrees sharper than the rear corners, and let the roof at the front intersection rise up so almost all the roundover is in the top sheet of foam, your eye can't pickup the width in a large radius, but it can see the reflection. That puts the flat reflection line in the "Right spot."

At the rear, set it so almost all the radius is cut in the side panel so the top has a "dart" cut out of both sides.

Dropping the stern end 3/4 puts the slightest high spot directly behind the intersection of the front of the dodger and the roofline, but it will drop the visual height across the top that extra 3/4 of an inch at the cockpit.


Cheers,

Zach

[DennisDW]

Thanks everyone for the design and construction suggestions. I have settled on a final look and have gotten a good start on construction. All the foam is on the mold and the outer layers of glass are in place.

I have used the flatter curve to the roof and leveled it out a bit. I do have overhangs. I like them. The next questions will be about the window shapes. I'll kick that down the road as I need to finish the rough dodger.

So many of you have been helpful. Not just opinions but reasons behind them. I am a member of Mensa and have subscribed to a few of the discussion groups. There is a lot of yelling and blustering about the smallest of things and yet here I have found kind, cogent ideas without the blow hards. The group intelligence of CF far exceeds Mensa and is far, far friendlier.

I'll post photos as things come along.
Yours,
Dennis

[DennisDW]

An update; Grinding, grinding, grinding. Hot/itchy, hot/itchy....you get the picture.

The piece is rough finished and windows cut out. I'm finishing edges, fitting to deck and setting the overhead hatch. Fairing and painting soon.

I really like the way it looks. I think we got it right!
Cheers,
Dennis

[GrowleyMonster]

Wow, what a great thread!

I am fixing to do, some major mods on my 2-27 which will include moving the aft bulkhead aft to the after edge of the small bridge deck. Don't need all that cockpit space, and I want to be able to steer "indoors" lol! It will all start with a similar hard dodger, and the hard top will extend over most of the cockpit, for my solar panels. The tips here are going to be very useful as I create my franken-boat.

Yeah I know, it will be an ugly little thing, and not sail quite like she does now, but I am okay with those tradeoffs.

[Voyager269]

Even with this monster/suit i can´t get out all of the small glass fibres.
Hope to see your dodger - doghouse soon.
Taco.

[Cherp]

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

Classic. So true. We have a hard dodger on our 40ft CC. It is marine ply glassed. It looks really good. It was designed and made up in basic form by a previous owner of our boat and his friend in a weekend. I glassed it and fitted it. The architect had an amazing eye for form. I could not have done it.

[Matt Johnson]

Could you also get a good estimate of weight when you're done? Weight is one major issue holding me off from doing a hard dodger.

Thanks,

Matt