Dinghy Design

[Roger Long]

I don't mean to steal Roger's thunder, but there are places on the web to get the plans you seek for free, with dimensions.

One thing you can't steal:

Way back when there were still buggy whip factories and the .com domain extension was only a year or two old, I put a set of plans on the net for free. A friend who was then an editor at PC world searched around and determined that I was the first person to make plans for a boat freely available to the public on the new medium. This was before search engines so he could be wrong but no one has ever disproved it. There wasn't much to search in those days anyway. I was customer number 12 for the first ISP in Maine.

 

[Ross]

Roger, I have a question concerning your dinghy design. Do you show access to the buoyancy chambers in your finishing details? In the Nymph that I built I placed extruded styrene foam beneath the longitudinal seat. Payson didn't show any.

 

[Roger Long]

Do you show access to the buoyancy chambers in your finishing details?

I didn't get that far. What you see in the links above is what you get. I would probably just install one of those plastic pop cover deck plates in each chamber and drill a hole for a drain plug and cork.

 

[Ross]

I didn't get that far. What you see in the links above is what you get. I would probably just install one of those plastic pop cover deck plates in each chamber and drill a hole for a drain plug and cork.

I was figuring on something like that. Did you figure 3/8 plywood?

 

[Will Sail For Food!]

Roger's plans are free with dimensions.

I'm sorry I thought I remembered reading in the thread that you'd have to use graph paper to enlarge it to full size, my mistake.
I guess I worded my response wrong, I did not wish to come off as unappreciative as I've read some of Rogers posts and some of his website. I find Roger to be informative, and also enjoyable to read.

 

[Roger Long]

I was figuring on something like that. Did you figure 3/8 plywood?

1/4. It's going to be heavy for a dinghy because of the size so you would want to save weight where every your could. I would use 5 or 6 mill metric plywood if you can get it to save some more weight and be a little more careful with the boat. If you have davits or plan to always tow, go for the heavier stuff.

 

[Ross]

Roger I have considered using corecell for such as this. The cost of marine grade plywood and corecell are not very far apart. I have worked with both.

 

[Hermit Scott]

Will sail for food- Rogers plans will have dimensions, however try to imagine somehow trying to draw all those curves onto a piece of plywood lifesize. The method using graph paper is to enlarge them to life size. You put a grid on the plans then you draw a corosponding grid on the plywood life size. Then fill in all the squares. Time consuming, but another option is Kinkos, and have them print the pieces on their banner printer. But that may cost alot.

 

[Roger Long]

try to imagine somehow trying to draw all those curves onto a piece of plywood lifesize.

It goes much faster than you think. You need a strip of wood about 10 feet long and 1/4 x 1/2 inch and a stack of bricks to draw the curves smoothly, a carpenters square, and a long straightedge. If you haven't got the patience for the afternoon it would take to draw these patterns out, you would run out of gas long before finishing the boat.

What is really great is to get a half dozen people together to build boats like this. After you have the first patterns cut out, the rest are just a matter of running a pencile and a saber saw around them.

 

[Ross]

A drywall hanger's "Tee" square is a perfect tool for these layouts. Alan Vaitsis recommends a box of ice picks, I use 4d nails to mark the points and then bend the batten to the nails. My problem is reaching across a 4 foot wide sheet.

 

[Roger Long]

My problem is reaching across a 4 foot wide sheet.

I crawl across when I do things like this. I could do it even when I was a year old

 

[Ross]

I crawl across when I do things like this. I could do it even when I was a year old

I gotta build a lower table.

 

[sailingdog]

I gotta build a lower table.

or get longer legs.

 

[William12213]

There are completed dimensioned layout drawings for drawing the parts directly on the plywood. No full size patterns.

This is the way I like to build them...full sized plans are more of a pain IMHO

 

[Ross]

or get longer legs.

I think it is my front legs that are the problem.

 

[Ross]

This is the way I like to build them...full sized plans are more of a pain IMHO

Unless the paper the plans are printed on is moisture stable there can be errors just from starting on a damp day and finishing on a very dry day.

 

[Hermit Scott]

I have a gallon of resin and just ordered 10 yards x 50"wide of 24 oz. fiberglass cloth. I have to make the backing plates for my through hull flanges, but I want to start on a dinghy also.
Does anyone build a mold and make a solid fiberglass dinghy? Are these not as strong for the weight they will have? And what happens if you don't use marine plywood? I understand there are unfilled voids in in regular plywood. Does water get in there some how? If the plywood gets wet isn't is screwed anyway?

 

[Roger Long]

I understand there are unfilled voids in in regular plywood.

Not marine plywood. If you don't want to pay those prices, ask for floor underlayment. It has no voids because it's intended to go under tile or linoleum and heels would go through. Most of it is Luan which isn't very rot resistant but will last years if you don't let your dinghy sit with water in it and keep it maintained. Plywood is pretty rot resistant anyway because all the kiln drying and processing kill the fungal spores and new ones have to get in through unsealed areas. The glue lines also hinder the flow of water and spores.

Unless you or a friend have a mold, I can't see any fun or worthwhile result building an all glass dinghy.

 

[shemandr]

Its a nice design, Roger. I particularly like the floatation features. The Peanut Pram I built didn't have that and I could probably never get registration for it. And, the double skeg - why didn't I think of that. Getting in and out from the front is very handy at most digny docks too. What do you think it would weigh?
We do motor ours - I doubled the plywood on the stern and have had no problems. I do restrict use to fairly calm conditions. For tootling, half speed on the O/B is fine.
A nice detail can be a transom handle to help carry it. It can be as simple as a oblong hole.
Got any Kyacks?

 

[Roger Long]

Got any Kyacks?

http://www.rogerlongboats.com/Boats.htm#Canoe

It's more accurately a double paddle canoe. It's a fairly heavy boat intended to carry a lot of gear on long camping trips. It's about 75 - 80 pounds and more oriented towards comfort and exploring than covering distances. I've gone 25 miles in a day in one but it won't do the 40 that more slippery sea kayaks do. OTOH it's a boat you sit in. You can eat lunch, change your pants, keep binoculars handy, and other things that would be difficult in a sea kayak. I've even caught fish from one. The decks are strong enough that you can run it up on a beach and walk off over the bow without getting your feet wet, an important feature in Maine waters. You can also usually launch with dry feet.