How fast can I build a dinghy?

[Bobobolinsky]

Could put an auxilliary transom mount on for the lickle O/B and kill two birds with one stone.
There's a few dingy plans on ebay for little money. A friend, just put two transoms in the middle of a dingy, and cut it in half to make a nesting pair. There is always Trifle for the price of Fred Binghams book, which is instructive and a good read
Boat Joinery and Cabinet Making Simplified

 

[barnaclephill]

I have a folding woodenwidget and have found that it rows at 1.9kts over almost a mile in an old mooring, so the estimate is right.

The www.woodenwidget.com I built in about 30 to 40 hours, plus time for the glue/paint to dry. With the w'widget/flapdoodle/handy andy the lorry/truck curtain material is held between 2 pieces of 6mm ply, caulked with bathroom silicone, and held together with half inch screws, 8 or 10 guage. My w'w has only slight abrasion on the fabric after 3 years so far. Think of it this way: instead of compressed air making the tube of fabric rigid, it is wooden struts or panels, much like skin over a ribcage. Think St Brendan's (re-enactment) boat. Here the fabric was called Ripstop600 or 400, and a cut made by scissors was not able to be extended, not even a millimetre, when I tried pulling it apart. So it's good stuff.

http://www.svensons.com/boat/?p=RowBoats/HandyAndy is the site for the Handy Andy with the rigid floor, much like the Flapdoodle, just less curves. The w'widget site has plenty of photos too, as well as a sample page of instructions, but you'll get the idea from the HA free plans. The WW concept can be extendable.

Another idea is the PBO article attached.

 

[Graham_Wright]

Not remotely what you are looking for but a friend of mine built a coracle in a day! Having previously marked out the appropriate saplings in a nearby wood, he launched the same day as he started construction;- and obviously capsized!

 

[prv]

Could put an auxilliary transom mount on for the lickle O/B and kill two birds with one stone.

Do you mean on the yacht, for stowage? Afraid that's not really going to work - the motor would either be clouted by the mizzen boom, or so low as to be at risk of being swamped at sea. Besides looking horrible

There's a few dingy plans on ebay for little money.

Sure, but I've already picked a design which has a good pedigree, a fair amount of information available, step-by-step build logs with pictures, and a forum of fellow builders. I'm open to mentions of radically different designs I haven't come across, but if it's a conventional stitch-and-glue nester then I've already made my choice.

A friend, just put two transoms in the middle of a dingy, and cut it in half to make a nesting pair.

I did consider that, but I'd be a bit concerned whether the front would actually fit into the back if not designed for it. To get minimum length of the package, the back needs to be almost entirely full of front, and that could be tricky with widths at crucial points. You could certainly make something that worked, but it might end up longer or higher than something designed for the job.

There is always Trifle for the price of Fred Binghams book, which is instructive and a good read
Boat Joinery and Cabinet Making Simplified

As it happens, I have that very book on the table here right now (was looking up some pretty joints for the electrics box I need to build). Problem with Trifle is that she's nearly 12 feet long, so even with an ideal split I'd have a 6 foot package (fnarr fnarr) and nowhere to stow it.

Cheers,

Pete

 

[PaulJS]

Can I suggest an inflatable canoe/kayak?
I've got no experience of them, but have heard that they paddle well, and some of those on ebay are supposed to be able to carry a family...

 

[prv]

Can I suggest an inflatable canoe/kayak?
I've got no experience of them, but have heard that they paddle well, and some of those on ebay are supposed to be able to carry a family...

Got one. It's rubbish

You can fit two people in it easily, could probably cram in three, but it feels very unstable. I think two canoeists would be fine, but I'm not one and even if I learned, my friends still wouldn't. There's no way I'd get in it in shore clothes, which rules it out for the purpose of getting to the pub or to go shopping.

It's also quite directionally unstable - every now and then I'll end up spinning round sideways, especially if I put lots of power into the stroke. I hope to fix that with a plywood skeg, as I do quite enjoy using the thing as an activity in itself. Unfortunately though it's not the answer to this question.

Pete

 

[PaulJS]

Ahh... I'm so glad that I mentioned not having any personal experience!

 

[bedouin]

Got one. It's rubbish

You can fit two people in it easily, could probably cram in three, but it feels very unstable. I think two canoeists would be fine, but I'm not one and even if I learned, my friends still wouldn't. There's no way I'd get in it in shore clothes, which rules it out for the purpose of getting to the pub or to go shopping.

It's also quite directionally unstable - every now and then I'll end up spinning round sideways, especially if I put lots of power into the stroke. I hope to fix that with a plywood skeg, as I do quite enjoy using the thing as an activity in itself. Unfortunately though it's not the answer to this question.

Pete

I looked at these at LIBS a couple of weeks ago as I fancy one as a run about to replace or augment the tender.

It struck me that, rather like inflatables, they ranged from toys to serious kit. The blurb certainly suggests that some of them are very competent

 

[snowleopard]

My experience may be some help as I'm part way through building a stitch & glue tender:

I designed it by dismantling an old Mirror then re-drawing the panels to improve the shape for my purposes. The panels are made of honeycomb sandwich with a kevlar outer skin. You could do exactly the same with ply and it would be much quicker but heavier.

I joined the panels with cable ties, tacked it with strips of glass then removed the ties prior to taping the seams. In the pic you see it ready to take the outside tape. Gunwales will be fitted by splitting 1" underground water pipe, pushing it onto the edge then wrapping it in glass tape.

I have fitted a box in the bottom just in front of the transom that will hold a wheelbarrow wheel so I can trundle it around by lifting at the bow.

As I took the Mirror apart I remembered how much fiddly stuff there is in wood construction - lots of fillets & stringers. Pretty time consuming even if everything is pre-cut. You can save a lot of that by just using tape on the joins though buoyancy tanks can be tricky when you can't get at the inside of the seams.

I think 2 weekends is optimistic but a full week with 2 or 3 people could get you to the bare shell stage.

 

[prv]

(Inflatable canoes)

It struck me that, rather like inflatables, they ranged from toys to serious kit. The blurb certainly suggests that some of them are very competent

This one is not a toy; it's made of heavy material like a proper inflatable dinghy, and is advertised for use on white water. It even has straps to hold you in the boat while descending rapids (note it's a "Canadian" canoe, not a kayak). I'm sure in the hands of a pair of skilled canoeists it would be a very capable boat for the purpose. I'm equally sure that it's not the right craft to travel back from the pub in

Pete

 

[prv]

My experience may be some help as I'm part way through building a stitch & glue tender:

Absolutely, yes. This is what I was hoping to solicit.

I think 2 weekends is optimistic but a full week with 2 or 3 people could get you to the bare shell stage.

Cheers. That's notably longer than most others on this thread seem to think, but more like the published experiences of others who've actually done it. I guess I know which side's more reliable

In your experience, what is it that takes the time? (in a from-plans build, not your own dismantled-Mirror high-tech panel approach). I ought to be able to mark out the panels in a morning, shouldn't I? And cut them out after lunch? Wiring the panels together: the following morning? Get some initial "tacks" of epoxy in, let it go off, then store the shell for the week. Could I do fillets, internal and external taping in the following weekend? I'm not quite sure of the sequence, but it doesn't sound impossible.

Where am I underestimating the time required?

(From what I can see, this boat doesn't have much in the way of fiddly wooden "fillets and stringers". The only piece in the shell apart from the panels themselves is a strip along the outside to form a keel. Then the gunwales (I like your pipe idea) and a few bits and bobs like breasthooks, but I'm counting those as separate small jobs for evenings.)

Thanks,

Pete

 

[snowleopard]

Where am I underestimating the time required?

If you are starting with fill-size templates the panels will be fairly quick to mark out but if you have to do any drafting it will take a lot longer.

Cutting out is pretty straightforward.

It took me a full day's worth of effort to pull the panels into shape and stitch them together. The joining of the seams was in a number of stages - stitch, tack, remove stitches, tape inside, turn over, smooth outside seams, tape. Each step takes a while and there are 3 delays while you wait for tape to cure.

What really takes time is all the little jobs not directly involved in the construction, e.g. you'll need to build a couple of cradles to hold the hull while you work on it. Just moving stuff around and clearing space for each operation takes time. Cleaning the resin handling equipment needs to be done thoroughly after every process; a trivial thing like cleaning cured resin out of the mixing pot takes 10 minutes every time!

Another thing to factor in is that your panels won't fit perfectly and you'll spend a few hours trimming little by little. Positioning bulkheads accurately is a fiddly job and could take an hour each.

Having built a number of boats including a 39 ft tri and a 40 ft cat I am pretty realistic about the time it takes.

An example of how time-consuming little jobs are, my tasks today have been - Move the hull out of the workshop & set up for sanding in the yard: 30 mins. Smooth the outside seams and grind back the tacking strips. 1 hour. Shift the boat back indoors: 15 mins. Mix filler and apply to gaps in the seams: 45 mins. Wait for filler to set: 2 hours. sand filler: 20 mins. Cut strips of glass for taping outside seams: 30 mins. Mix resin and tape outside seams: 1 hour.

 

[AliM]

two comments

If you go for an inflatable kayak, then look for one of the proper quality ones (eg Sevylor), not the toys. They are much more stable than plastic/wooden kayaks, and store in a bag about 1+.6x.3 m3 bag. Heavy but carryable. They are fun to paddle, but there's not a great deal of room in even the largest of them.

If you make a dinghy yourself, it's the varnishing, painting, waiting for glue to dry... which takes the time. Two weekends sounds pretty short to me. We are halfway through a 180cm adaptation of a flapdoodle folding dinghy. It's taken more time than that, distributed over a couple of months. It's been great fun though. We expect it to fold into 180x15x40cm3. I'll post pictures when it's finished.

 

[prv]

Each step takes a while and there are 3 delays while you wait for tape to cure.

I was kind of expecting epoxy curing too quickly to be my main problem, not too slowly . Especially in the larger quantities involved in this sort of work. If it's slow, I guess I can take the fan heater to it as I've needed to do in the yard in winter.

What really takes time is all the little jobs not directly involved in the construction

That's certainly true. I'm rewiring the boat at the moment and it's depressing how little I actually get through in a day, taken up by all the little bits. I was hoping this job would consist largely of bashing big chunks of boat together, hence a minimum of little tasks, but I guess that just means I haven't analysed it closely enough

e.g. you'll need to build a couple of cradles to hold the hull while you work on it.

Fine - I have a couple of trestles I knocked up for my spars to lie on while varnishing. Might not be wide enough for a dinghy hull, but I can chop-saw and screw-gun a couple of two-by-fours across the tops in minutes.

Cleaning the resin handling equipment needs to be done thoroughly after every process; a trivial thing like cleaning cured resin out of the mixing pot takes 10 minutes every time!

I avoid cleaning wherever possible. The pumps don't need it as they only see one component, the mixing pots are disposable plastic pint glasses, and I use B&Q budget paintbrushes at 20p a pop and throw away after each batch. I've seen a nifty bit of advice to use an old frying pan as a working pot for big batches, to spread it out so it doesn't cure so quick, and I might well do that. I will experiment with putting the pan inside a freezer bag though, and ditching the bag when the batch sets. I don't have time to waste cleaning epoxy off things.

Another thing to factor in is that your panels won't fit perfectly and you'll spend a few hours trimming little by little.

I'll do my best not to take hours . I'll make vigorous use of my power-file to get them close-ish, then whack lots of micro-fibres into the gap. Did I mention the rough-as-arse aspect?

Having built a number of boats including a 39 ft tri and a 40 ft cat I am pretty realistic about the time it takes.

Yep, and I'm grateful for your experience. I'm just hoping, perhaps naively, that I can sacrifice finish quality in exchange for speed. Call this version a prototype, to see if it works well, and maybe I'll build the neat one in the future. (I would like to do a proper job one day, that I can be proud of, but this isn't it.)

An example of how time-consuming little jobs are,

...interspersed with how I plan to cut corners to save time

Move the hull out of the workshop & set up for sanding in the yard: 30 mins.

Building the whole thing on the patio, as I don't have a big enough indoor space. Stored against the fence under a tarpaulin. I'm doing this early summer, and if the weather doesn't suit I'll do something else that day anyway. So two minutes to move the tarp and pull it out from the fence.

Smooth the outside seams and grind back the tacking strips. 1 hour.

Ain't gonna bother. Just a quick once-over with a coarse disk if necessary to remove sharp edges that the tape won't go round.

Shift the boat back indoors: 15 mins.

Still on the patio.

Mix filler and apply to gaps in the seams: 45 mins.

Can't reasonably speed this up. You have experience on your side; I have lower standards. Call it even.

Wait for filler to set: 2 hours.

Blast it with a 2kw fan heater, I'm sure I can speed it up a bit. People cure epoxy in ovens, so I assume this doesn't harm the final properties.

sand filler: 20 mins. Cut strips of glass for taping outside seams: 30 mins. Mix resin and tape outside seams: 1 hour.

Likewise, I can't speed this up, it's the meat of the build.

Am I still being unrealistic? I probably am, but hopefully not excessively.

Pete

 

[prv]

If you go for an inflatable kayak, then look for one of the proper quality ones (eg Sevylor),

Mine is a Gumotex Palava which, while less known than Sevylor, feels of equal or better quality. It's sold for white-water and canoe-trekking work where you need to be able to carry the boat into your chosen piece of wilderness.

If you make a dinghy yourself, it's the varnishing, painting, waiting for glue to dry... which takes the time.

Ye gods man, I contemplated building this thing out of OSB, and you're talking about varnish?

A bit of paint will be necessary to keep the water out, no getting round that. Or perhaps I could use the tin of polyester gelcoat I have in the shed? (had to buy a whole tin for a smallish repair).

As I mentioned above, epoxy can be sped up with a bit of heat. I've never heated it specifically in order to go fast before, but when I've used a heater to bring a cold work area up to adequate temperature, the epoxy near it went off quick. Unless someone tells me I'm weakening the final result by doing this, I think it's a useful technique. With a build like this, though, I'll probably need all the open time there is to get things in place.

Pete

 

[DownWest]

PRV, between you and SnowL, you seem to have covered the bases. There is a build in shortest time comp in the the US with Wooden Boat. Instructive. Use PU glue and chine logs, and nails.
I built a 6ft pram in a week, including the rig and all fittings. As I was 11, I recon I could do it a bit quicker now.
Fear of mistakes is a great slowing facter, hence the speed of a professional in most work.
A couple of week ends should be good. A tip, for a nesting dinghy, build it complete with two bulkheads at the join. Seperate them with piece of cardboard. When you cut it in two, the card will guide the saw between the bulkheads.
As said, the fiddly bits take the time. I probably took twice the time to 'finish' the hull as it took to make the basics. This is for an Oughtred 15ft double ender.
Good luck,
A

 

[snowleopard]

While cutting the panels your jigsaw blade breaks, allow an hour to nip down to B&Q for a new one! Working outdoors with resin - it will rain. Need SWMBO to hold something while you fix it - she's washing her hair.

One thing I learned to cater for in IT project planning was the fact that all plans are made on the basis that everything will go right. The only thing certain is - that won't be the case.

 

[DownWest]

Where's that "Dam! I got my ++++ stuck in the ++++" emoticon.
SnowL, Spot on

 

[prv]

One thing I learned to cater for in IT project planning was the fact that all plans are made on the basis that everything will go right. The only thing certain is - that won't be the case.

Point taken

Pete

 

[prv]

Fear of mistakes is a great slowing facter, hence the speed of a professional in most work.

Very true. Hence the liberating factor of knowing from the get-go that I'm not aiming for perfection. I'll also probably get in an extra sheet of ply (I'll always find a use for it) just so that a major marking / cutting cockup doesn't completely derail a weekend's building.

A tip, for a nesting dinghy, build it complete with two bulkheads at the join. Seperate them with piece of cardboard. When you cut it in two, the card will guide the saw between the bulkheads.

Yep, that's the technique in the plans for Two-Paw.

Pete