1st build , jr dingy out of plywood

[NSBoat]

hi
I am really glad i found this forum , there is a huge amount of very good info here . this is my 1st post , and my 1st build . I have been thinking of building a boat for years , and finally plan to do it this spring . and hope to have it built by mid may in time for the shad season , and a bit of mackerel fishing later in the season .

I am starting very basic with a plan i found online called the " Junior " it is a small dingy that should easily hold 2 ppl and gear for fishing on small lakes for bass and trout . At 9ft long it should fit on the back of my truck without the need for a trailer . with a finished weight of around 100 pounds be manageable for 1 person .


it also looks reasonably simple to build , I am a competent wood worker but have never built a boat before .

here are the plans :


http://svensons.com/boat/?p=RowBoats/Junior

I am planning on using exterior grade good both sides 3/8 plywood , not marine ply . I figure that this boat will not be in the water all the time , and will be stored indoors in a garage when not in use , so marine ply is overkill , and expensive for the intended purpose . plus I plan to paint the boat so if the wood underneath does not look great i don't care , no one will see it, as long as it is structurally sound I am happy .

I originally planned to cover the outside with fiberglass cloth and the inside with epoxy , but i was reading that this may not be the best option , because wood sandwiched between the fiberglass and epoxy like that can't breath and will rot . it was suggested , that is is better to cover the exterior with fiberglass , and reinforce all the joints with fiberglass mesh but leave the inside of the boat with just primer and paint . anyone have any thoughts on this ?

I would also like to build in flotation . I am thinking that I can add flotation in the bow section under the seat , and under the stern seat ,and I was thinking under the center seat . how much is necessary ? my thought again was to build compartments of plywood epoxy both sides and fill the space with foam .

has anyone built this boat b4 , and can they offer any advice / insights as to if this is a decent little boat . what I need in a boat is a boat that I can use for lake fishing on small lakes , it has to fit on the back of my ranger , and be light enough to be handled by 1 person . It should be able to operate with a small motor and or oars , be stable and safe for 2 people and gear . I don't plan to use it in bad weather , but it needs to be stable enough that if I get caught on the lake I can make it home . I also need a boat that is easy to handle for a novice boater .

from a build point of view I need a plan that is easy to build for a 1st time builder , plus one that is fairly quick to build , I want to build and assemble this in about 3 or 4 weekends and be able to use it for most of this fishing season .

of all the plans I have looked at , this one seems to fit my needs in both what I need in a boat and what I need a plan .

any advice would be appreciated . particularly on the plans themselves , is this likely to be a good little boat , or am i missing something ?

I will post some pics as I get started , hopefully in a few weeks. fishing season is only a month away :)

[James McMullen]

Free plans like this are worth about what you paid for them. I would suggest that you buy some plans from a modern designer who knows the modern and correct way to build lightweight plywood boats. For example, Sam Devlin (http://www.devlinboat.com/designcatalog.php) has several little boat designs similar to that one, but designed for modern stitch & glue techniques. Such a boat will be much stronger and lighter weight as well as being substantially quicker and easier to build.

Exterior ply is a false economy and a serious mistake. You'll spend every bit as much time and effort building a short-lived, weak and heavy boat out of shoddy materials as you will building a decent boat out of suitable materials.

[David G]

That's a pretty cute little boat. But I have to agree with James. There are such a lot of designs out there that are just as cute - if not more so - and are designed for modern materials. Many of them come with extensive building instructions, email access to the designer, and/or support groups (eg. Yahoo Groups) for that particular design. They can help you decide whether that boat is a good one for your circumstance. They can help talk you thru any bits of confusion that come up during the build (esp. helpful for a first-time builder). You might even stand a chance of connecting with another owner in your area... and boating in company with them at times. Devlin, as mentioned is one such designer. Others include: Bolger; Storer, Michalak, Lillistone, Joe Dobler, David Nichols, Gavin Atkin (whose plans are also free), Welsford, Selway-Fisher, Graham Byrnes, Joel White, Shorty Routh, Gartside, Mertens, Mark Bowdidge, John McCallum, Warren Messer, Warren Jordan, Tracy O'Brien, and more.

Heck... Duckworks has a great index. Good place to start. Here's the link:

http://www.duckworksmagazine.com/r/plansindex/prams.htm

[mmd]

Hey, NSBoat; how's it goin'?

First comment - and no insult to David and James intended - but for every boat design touted here, there will be detractors. A lot of what they say will be right, too, but... Have you ever bought a computer? (Of course you have, or we wouldn't be talking to you!) Have you ever noticed that as soon as you bring it home, somebody from the neighbourhood or at work tells you that you should have bought a different one 'cause it's better? Boat plans are like that.

My take on what you are doing is this: If you use exterior grade plywood, it won't cost as much as marine grade ply and it won't last as long. Ya gets what ya pays for. As this is your first boat and you are bound to either make mistakes or get hooked on boatbuilding and want to build a different/bigger/better boat almost immediately after launching this one, it is OK to build cheap and lower-quality. It's great practice for the next one.

As for "to glass or not to glass", I'd glass the exterior. It's better protection from scrapes and dings, and you will certainly get those loading and unloading from your truck. Leave the interior unsheathed and keep it painted. Glassing the exterior will make for longer-lasting surface appearance, too.

For floatation I wouldn't build any enclosures. Get closed-cell foam (the blue foam that is used for insulating building foundations is just fine) and glue up blocks to fit under the seats - you can carve the stuff to shape with a bread knife. Use nylon packing straps to hold the blocks in place, secured with screws and washers to the underside of the seats. A boatbuilder friend has little dacron covers made by a seamstress friend to make them look pretty. Figure that your 100 lb. boat will provide about 80 lbs. of bouyancy when fully submerged, and that you would like to keep your little outboard and your tackle box and beer cooler from sinking the ship (the concept of two of you rowing to shore in a completely flooded boat is not likely - your best bet is to be able to bail madly while beside the boat and re-enter when mostly afloat). As fresh water weighs 62.5 lbs per cubic foot, and you might be able to squeeze 5 cu. ft. of foam blocks under the seats, the whole thing should provide about 350 - 375 lbs of floatation - enough to keep your stuff from sinking and, on a good day, maybe keep you in the boat by yourself to bail.

Keep the boat dry when not in use and maintain the paint and your little boat should last five to ten years. Have fun!

[Lewisboats]

I agree with MMD...and would add that 3/8" plywood is overkill for a 9 ft boat like that. You would be fine with 1/4"...at least for the sides if not the whole thing. It would probably save your back a bit as well as some money.

[luckystrike118]

Free plans like this are worth about what you paid for them. I would suggest that you buy some plans from a modern designer who knows the modern and correct way to build lightweight plywood boats. For example, Sam Devlin (http://www.devlinboat.com/designcatalog.php) has several little boat designs similar to that one, but designed for modern stitch & glue techniques. Such a boat will be much stronger and lighter weight as well as being substantially quicker and easier to build.

I agree with James. For a sitch n' glue Boat take a sitch n' glue design. Take a modern plan

I have used exterior plywood very successfully in both ways ... economically and in the matter of quality. I don't know if the standarts are the same in Germany and the US, but if the glue used to make the plywood is ok and waterproof, the veneers are laid out carefully and the thicknesses of the veneers are all the same with a good sized top layer .... why not? Ok, you have to check the edges of the ply all around looking for voids in every sheet you pick.

Grrreetings from the North Sea Coast, Michel

[wizbang 13]

6mm for bottom, 4mm for sides, epoxe filets but no tape. build the 2nd one of marine ply An inflatable seat from a "zode" makes good flotation

[minitugboattodd]

I have built a Sam Devlin Polliwog stitch and glue design and really like the boat and its rowing fun. I also have a 2HP Honda outboard I use for it and it pushes it along great. I used marine plywood and mahogany for all of the parts. The marine plywood was not the real expensive stuff like Okume, because it was more expensive to ship that plywood to where I live than the plywood cost itself.
As this is your first boat, I would build it out of the cheaper marine plywood like I did. It will last a long time if properly fiberglassed on the outside and epoxied on the inside. You also need to varnish any brightwork to keep the UV out. Definitely fiberglass and epoxy the outside of the boat!! It is much to easy to damage without it.
Go to my blog below to see a picture of my first boat, the Tinytanic.
I am now in the process of building a MiniTug boat called the "Perfect 10" from Berkeley Engineering. You can see the process so far on the blog I have started for it at http://toddsminitugbuilding.blogspot.com/ . I am doing this boat pretty slow, but I should have it done by this summer. This is only one of the major projects I am tackling at this time.
Any design you choose should be determined by your needs. I chose the Polliwog design because I wanted to learn the process first before building a bigger boat, and also to put this dingy on the back of the Sam Devlin design Surf Scoter I am going to build someday! I swear I will get to it someday.

[McManusBoatWorks]

I would also encourage you to look into Sam Devlins designs

The Guppy is a sweet little boat at about 9.5 feet.

It rows effortlessly.

For the first time builder Devlins designs are a very good choice and at $45 bucks that are worth the money. Why?

He has a book that lays it all out step by step

His plans are spot on and no lofting is required.

All the parts fit the first time.

If you get into a tight his staff will give you a pointer or two.

$45 bucks is money well spent

[NSBoat]

thanks for all the advice . I am about ready to get started , I found another plan that I think will be easier to build , and will be a slightly larger boat about 11 feet .
I found some good 3/8 plywood , not marine but there are very few voids that I can see , and they are small . I bought some resin , and some fiberglass mesh from my local industrial supply , i think I got a good deal . a gallonof resin with a tube of hardener was $35CDN , and the mesh sheets were $14 each for a 3 by 9 foot piece .
which brings me to my question . I still plan to fiberglass the exterior of the hull . how ever I want to make sure the stuff i git will work as intended . the resin is polyester resin , and the fiberglass mesh cloth i got is the tangled weave type , it does not have the uniform cloth like weave that i see many ppl using here .
will this work ?
I hope to get this thing started in the next week or so

[Candyfloss]

You are not listening are you. Throw the polyester away, it will not stick. You must use epoxy.

[DGentry]

No, your fiberglass mat won't work. You need fiberglass cloth. 6oz works OK for a boat that size, depending on what you use the fiberglass for. You can buy rolls of fiberglass "tape" for covering seams. Try www.Raka.com (http://www.Raka.com)

Hundreds or thousands of wood boats have been made with polyester resin, but . . . epoxy is much better. Much. Polyester resin apparently doesn't adhere to wood very well - not a good thing if it's holding your boat together.

That being said, the polyester resin I've used on boats has worked just fine - though I did not use those boats hard.

What design did you decide on? Also, allow me to suggest you get a book or two - "Instant Boatbuilding with Dynamite Payson,"
by Harold Payson, and "Boat Building for Beginners and Beyond," by Jim Michalak, are indispensable primers for simple plywood boat construction - plus they have some plans.

Do check out the shop tips section of CLC's website. Here's some good info, with pics, on epoxy: http://www.clcboats.com/shoptips/epoxy_and_fiberglass/

Good luck - and keep us posted!

Dave Gentry

[James McMullen]

NSBoat. . . .oh dear! :(

". . not Marine. . ." is not the safest choice.

". . .very few voids I can see. . ." is still too many voids for comfort.

"tangled weave" must mean FG mat. That's not the right stuff.

And then there's the polyester resin which has very poor adhesive qualities. You're not going to want to use polyester resin to glue wood together the way you can using epoxy resin.

You're making this an awful lot harder on yourself than you need to. Please check out those books Dave mentioned at the very least before you end up making something that is structurally unsound and potentially dangerous.

[wizbang 13]

Return to the 8 footer while your at it.

[davebrown]

you are obviously a hard-headed sort, which might be the most important characteristic required to actually build a boat. congratulations.
i built a bolger gypsy out of exterior 1/4 ply for the sides, and 1/2 in exterior for the bottom. i taped the seams but did not glass the bottom or sides. i had a trailer, so weight wasn't number one on my list of criteria. the boat wasn't as heavy as you might think because the glass, which i omitted, does add weight.... i beat the devil out of that boat, and it was in fine fiddle (or is it fettle? ) when i gave it away. so i saved myself 50 cents, and because of the low grade wood, didn't spend much time upkeeping the boat, meaning, it usually looked rather poor. but it can be done. the problem with 3/8s is it is usually 3 ply, and prone to warping, etc. if you are a skilled carpenter,then, as nearly everyone has said, spend the extra money for marine ply. do you need three sheets or two? okume 1/4 can be had for about $60 a sheet, with a little research. so you are into the boat for $180 maybe, instead of maybe $90 for 1/4 acx? reinforce the bottom either with spruce or doug fir runners, or glass with epoxy. the epoxy and glass will likely run you less than $100, and certainly less than $150. so for under $500, you get a boat built out of good stuff....this is an amateur's opinion, but parallel to the pros above.

also consider the weekend skiff, by the improbably named richard butts, which can be shortened to 13 feet. if you use marine ply, you can get that down to around 100 lbs.

[Cuyahoga Chuck]

I gotta' give you my view. I am not a heavy hitter but I am the only guy here that spends most of his nautical time in an 8' pram. So, I'm full of opinions.
I built the D4 pram designed by the naval architect, Jacques Mertens. The plans were free and took some getting use to because they were in an old format that didn't print out that well. But everything is there. Two sail options with daggerboard, dagger, case and rudder if you want to sail. Airtight seat assemblies for floatation. These seats don't need foam and will give you more lb. of floatation because air weighs less than any foam. And mine have a watertight hatchs that can be opened for storage and for inspection. Never found any water intrusion so far but I leave the hatches open in the off season anyway. Mertens also includes a tutorial about how the hull is wired and glued. And if you have any questions he has an active on-line forum. Not a bad deal for free, is it?
What you get is a rock solid, vee-bottomed dinghy that is complete in every way but only 65lb. if you use marine ply. Weight is important to me because I cartop as well as pickup truck it.
Now for the contrarian view. Using exterior ply means it will check. The surface will develope a gazillion little splits. The cure is to glass everything but that's a hell of a price to pay just to make it look good. It costs dollars and piles the weight on. Epoxy is heavier than water and most of us use way more than we intend. By the time you pay for the glass and the epoxy your total cost won't be much less than if you bought the best BS1088 okuome.
A dinghy made of exterior ply will, already be 1/ 3rd heavier before the first dab of glass and epoxy is applied. And the hull does not need it for strength.
Since you are starting from zero download the free D4 plans. Even if you are not interested in the boat all the details plus the how-to will help get you up to speed about S&G boatbuilding.
http://www.bateau.com/freeplans.php
And here are some construction photos
http://gallery.bateau2.com/thumbnails.php?album=343&page=1
And a couple of dozen pictures of D4s that have been built. Mine didn't make the cut.
http://www.bateau.com/boats/D4/index.html

[NSBoat]

Thanks for your advice , it is appreciated . I don't mean to be hard headed but marine ply around here is running $90 a sheet , by the time i am done with taxes that's over $300 for the ply compared to the $60 i got the stuff i have now for .
the poly resin and the cloth mat were what my industrial supply store had , and it said on the package that they were rated for marine use .
total cost for a gallon the resin and the mat cloth after tax was $75 .
the closest marine supply about 45 min away wants after tax just under $200 for a gallon of epoxy resin and hardner , and about $90 for the same ammount of fiberglass cloth that i have as mat .

the plans i was going to use were not stitch and glue construction . I have bought a bunch of the lepage waterproof moisture cured glue and was planning to use that and brass screws for the construction ,which is what the plans called for . the resin coating i planned to apply was an add on i figured would be an extra measure of water proofing , seal the hull, and add extra strength to the hull .

I had a budget of around $300 for this project , and was hoping it was going to be a fun project that would yield a useful result , which i could go bass fishing in .

Like i said the plans i have are not stitch and glue . However i like the D4 plan and the weekend skiff looks like a nice boat ( especially if it can be dropped to an 11 or 12 foot boat ) .
I have a similar book on building canoes and kayaks , it looks very similar , and may be by the same author i will have to check when i get home .

i might be able to find a better source for epoxy and cloth .
how much square footage would a gallon of resin cover . would it be sufficient to cover a boat the size of the D4 or the weekend skiff ?

[Keith Wilson]

Throw the polyester away, it will not stick. You must use epoxy.Sigh. . .

Not to be too much of a contrarian, but yes, on clean new fir plywood, polyester resin will indeed stick. I know this because I built two stitch-and-glue boats using polyester resin and ACX fir plywood. The older one's 20 years old, the newer 13. They haven't rotted away or fallen apart, despite indifferent care. Not first-class efforts, as money was more important then, but they float. No, it's not nearly as good as epoxy. I wouldn't do it now.

Mat is for structures built of fiberglass; woven cloth is the thing you want. And you have to know the difference between layup and finishing resin. Finishing resin has added wax, layup resin does not. Polyester resin will not cure 100% when exposed to air, so there's a slightly sticky layer left on the surface of the layup resin which allows it to bond with the next layer, but makes it essentially impossible to sand. With finishing resin, the wax floats to the surface and seals it, allowing it to cure thoroughly, but preventing the next layer of resin from sticking to it. For sheathing with fiberglass cloth you MUST use layup resin until the last coat. You can also get little bottles of liquid waxy stuff that you add to the last coat of layup resin, which allows it to cure so you can sand it..

[atmartin]

Finally, I thread that I can legitimately contribute to.

Sometime around two years ago, I built a PDracer, which is an easy-to-build one-design with free plans. http://www.pdracer.com/

I spent about $100-$150 on the project.

I used luan doorskin (4mm I think) for sides and 3/8" exterior ply for the bottom. I framed it heavily with 1x2s. The entire structure is held together with gorilla glue. Clamping pressure was applied by brass screws, which were removed and filled with cheap-o putty prior to painting with exterior latex.

I've used the boat heavily, it gets in the water at least 2-3 times a week and is in my truck most of the time, bouncing around and tied down as I have a tiny pickup and it doesn't sit flat. I used it first with a sailing rig from another boat and a leeboard and now it sees full time use as a tender for my 25' plastic mothership.

I've gotten my monies worth, but take a look and see what I've learned:

http://img219.imageshack.us/img219/2196/goat3m.jpg
http://img63.imageshack.us/img63/734/goat2.jpg
http://img94.imageshack.us/img94/5536/goat1d.jpg

http://img62.imageshack.us/img62/6900/goat5.jpg
http://img687.imageshack.us/img687/6922/goat4.jpg

Lessons I learned:

-Brass corrodes to hell, at least the cheap-o Home Depot brass
-Boats, at least like this one, take a lot of beating and ply laminates separating sucks
-If this thing was in the water all the time, it would be a goner (longest it stays in is a weekend)
-Gorilla glue is strong and seemingly waterproof! It is the sole structural joiner in The Goat

Since I cheaped on the doorskin and didn't use epoxy/glass, I had to put a lot of framing in to keep the structure stiff. The Goat as been dropped, beat, and overloaded, but has held up thanks to this framing, but it also weighs close to 150 lbs. There is no way most people would want to lug this around. I am 24 and 240lbs. To lift this beast, I had to devise a system: I lay it on one side on the beach, squat underneath it and pull it over on top of me, then squat up and walk over to the truck. This sucks major nut after a long day on the water or cleaning out your bilge.

Anyway, there's the perspective of someone who is unskilled and with no interest in the 'beauty' of a wooden boat, but still agrees with a lot of what is said here. Since I built The Goat, I've been using epoxy and glass cloth for various work on my GRP boats and have gotten more comfortable with it and will use it on my next dinghy, which I hope to keep in the 40# range!

[bljones]

NSBoat, I've been there and done that. 25 hrs. of actual build time and approximately $250 built this:
http://i27.photobucket.com/albums/c175/bljones/newpics019.jpg

You don't have to spend big money, but you do have to spend your money smart. Ask the questions before you buy the material. To save money, mail order fiberglass and epoxy from Aircraft Spruce or similar.

[Keith Wilson]

BTW the old plan from Svenson's look perfectly OK to me, if unremarkable. Joel White designed a very similar little rowboat, Martha's Tender. Just build the damn thing. If it doesn't work out, build something else.


http://www.sailingtexas.com/Pics/picwoodenboat100d.jpg

http://www.sailingtexas.com/Pics/picwoodenboat100b.jpg

[Brian Palmer]

I will just add that in an 8 or 9 ft boat, a pram (squared off) bow will get you a lot more room and flotation (capacity, safety) than a pointy bow, especially if you are looking to regularly carry two or more people. And it will be easier to build. Finally, they row just fine as long as you have a good design that keeps the bottom of the bow transom clear of the water when loaded.

Good luck and have fun!

Brian

[NSBoat]

Ok so the project has been under way for some time now .
Weekend build my A$$$ .
I have been chipping away at it for over 2 months now . Everything seems to take 10 times longer than it should but i am in the home stretch now . the only piece i have left to make is the skeg and to glue and screw in the last few pieces . they are all cut and fit they just need final assembly .
I got real lucky at a yard sale and found a Johnson 4hp outboard for it , which i think should be perfect for the boat .
It is a nice looking hull so far , and quite light , i think it will easily be under 100Lbs when done.
I made a few minor modifications but stuck very close to the plans , mostly I just beefed up areas that looked light to me when they were built.

Things I have learned :
1 - Study the plans , when you think you know them inside out , study them some more , because you are sure to have missed something . Knowing how to read the plans properly is a huge time saver . I lost a lot of time trying to figure out how stuff was suppose to go together . it all went together the way it was suppose to , but because i didn't fully understand the plans i kept trying to figure it out when it was right there in front of me . THis will likely be less of a problem on a 2nd build but on a 1st build it cost me time.

2 - Budget 3 or 4 times the recommended time for everything . every thing seemed to become a time sink . even the simplest things took way longer than they should have . much of this was my in experience , but a good chunk was the fact that you need to wait for glue to dry and cure . hurry up and wait is something you need to plan for . planning to spend a hour or 2 every evening for 2 weeks would be a more realistic and efficent time management strategy than planning to spend a weekend or 2 , in a building marathon . the weekend or 2 will turn into a month or more real fast , because you constantly have to wait for one thing or another to dry / cure / soak or what not .

3 - A pram build would have been a lot easier and faster to build . bending plywood is a fiddly nuisance and a pain in the but , getting 2 bends to match up is a cause for much cursing and swearing . and a huge time sink .
( Having said that i do like the lines of the pointed front of the hull )

4 - the nit and stitch method of construction is probably the cheaper and faster way to build a boat like this .
I got realy lucky , I found gorilla glue for 99cents a bottle , and Brass screws for $3/100 , at a local clearance store Bargain Harley s . The same bottle of glue in walmart was $10 , and the same screws at my local Home Hard Ware were 20 cents each . I have gone through 8 or 10 of these bottles . and 2 boxes of screws easily , I also got marine paint there for $20 a gallon . if i had to pay full retail , I would have sunk $150 or so into glue and screws plus the poly resin and cloth. I was planning to resin the outside any way I could have bought the epoxy resin and built the thing nit and stitch for the same or less money .

I did find a decent deal on fiber glass cloth which i plan to use to cover the entire outer hull . cost me about $70 . I could have saved more by buying online , which i will do for my next project when ever that is .

all in all it has been a worth while project , and will probably have cost me around $400 for a 9'6" boat and motor , not bad .

I learned a lot , and I think the boat will be alot of fun , i would defiantly build another , and have a book on canoe building which i think will be my next project .

the one thing i need to know now is where to position the oar Locks .
is there a formula for this , or is it more a look and feel thing ?

I have some pics of the build I will post in the next week or so . It is a nice looking boat I think .

[James McMullen]

Oarlock centers go approximately 11" behind the rowing thwart assuming that both boat and oars and thwart heights and freeboard and rower are all of fairly average proportions.

[Lewisboater]

I go from the centerline from shoulder to hip and the length of my forearm aft of the center of the thwart. In other words bend your arms at the elbow, keep them right at your side and mark where your closed fist hits the edge of the boat when you are sitting upright on your thwart. You will lean forward and back during your stroke around this pivot point.