Thread: Building a dinghy - WIP

frist thoughts are steam or failing that towels and boiling water. If you dont want to do it on the moulds then build a jig on the ground perhaps and give it some prebend with the hot water etc. Another way maybe is to kerf it and fill with epoxy afterwards.

I did think of steaming, but would have to make something up that is 3.5m long and then be able to supply enough steam.

I like the hot towel idea thoughI reckon I only need to steam the back half as it has a far sharper bend.

Kerfing is the name I was looking for when talking about cuts across the keelson. All good ideas thanks.

I went out to the shed braved the sub zero temp and took a couple of shots - I will claim that they are WIP shots as well as giving an idea of the springback. THe funny thing is, I am sure the spring back was a lot more on Friday night when I initially did it. Perhaps it has settled enough, and is a bit heartening that steaming with a couple of towels might be enough to get me across the line.

I reckon a bit of spring back wont matter too much as the keel (which thickens towards the rear as well) will hold it a little and should be all stiffened up by planking.........hopefully.

The first 3 photos show keelson bent and held in place. I have let the middle rope go in the last 2, though I should have removed it all together as it looks a little confusing on reflection. There is no pressure through the middle in the last 2 photos, only clamped at the stem and tied down at the transom.

Bryan another thing is that you may want to think about putting some bracing on your moulds before you put any stress on them with bending timber around. They can move and upset the symmetry of your hull. Braces should run on the 45 down to the strongback and between one mould and another. I am also building an Oughtred design and have found that the lamination thicknesses seem a little too big to bend nicely and so have used thinner pieces with a lot more success. Are you sure that the keelson is supposed to be that thick in one lamination? In the pics it seems pretty heavy. also if you attach at transom first then pull down front you'll have more luck with the lever effect.

Thanks Andrew

I will brace the forms before I go any further, just havent got around to it, as there has always been more interesting things to do. I know its all part of the process, but a little tedious to do work that it not part of the final outcome.

The keelson is meant to be 20mm thick but it gets faired at the sides a fair bit, especially towards the bow and stern. It does say that you can laminate from 2 x pieces if you wish, but that is not high on my wish list.

Good idea on the leverage point. I can get it to go though, just not sure about whether it will stay when all is done.

Hey, if you are building a boat, where are the pics? Which one?

It's a Grey Seal and pics are started on the other forum but soon to come. I'll work on it tonight. I'm bad. Where's Taylor's Hill anyway?

I did a search and found those pics. Looks like a bit bigger project than my bathtub cruiser. Is the lead you were talking about in other threads for this boat?

Taylors Hill is a suburb out near Taylors Lakes / Keilor. Fair way from any water, but I dont think I will have to worry about that for a little while.

I had the Same problem with the kelson on the Auk. I went the cross cutting the inner face of the timber and filled it all up with epoxy but still managed to crack it in one place. If I had my time again I would go the laminated way. It may be a bit more time consuming but less risk of breaking anything and will reduce stress (on the timber and the builder). I also held down the Keelson with a ratchet tiedown on to an additional cross member on the buiding frame ( leave about 200mm over hang on the keelson and make sure the transom is secure). From memeory I think I also drilled a few holes where the dagger board slot will be and tied the keelson down to the molds using another tie down to the building frame.
Ian L

Dont worry Bryan I have three boats on the go for the last 10 years + and the smallest of them is about 12 inches on deck !!! And none of them is finished either !
You live just up the road from me - I'm in Coburg although my build is in the country. I'll have to come over for your turning party, probably be before mine.
BTW i've updated my thread

That's funny! I'm building the Hartley and I'm just in Heidelberg. Must be a Northern suburbs thing...

Ah-ha

I found the problem with the Keelson springback thingy.

It has bugged me for a few days, but I walked into the shed 10 minute ago, and it hit me. I was blaming the springback on the drop or rise to the transom (depending on which way the boat is facing - at the moment its upside down so Ill call it down).

It was actually the stem causing the problem. When I originally screwed the stem to the Building Frame, I checked the front face for plumb, and adjusted it before using a timber batten to fair the face that gets joined to the keelson.

When I reattached the stem to the BF I didn't check and it was 10-15 mm out. This translated to about the same at the joining face meaning the pressure I had to apply with clamps to close the join was a lot. I removed the temporary supports and plumbed the stem front face and the difference is significant. There is still a little spring back, but much better and I reckon will be fine with the stiffening provided by the planking and keel.

That description I just doesn't even make sense to me so here are the photos, showing a before and after even though I moved the clamp a little it still clearly shows what I mean - I think.

Re Kelson, been there done that. As per previous post I had all the dramas down the other end, but the auk is a bit shorter.
Ian L

Hi Ian

There is still a lot of pressure on the transom end, but it has definitely settled down. I reckon the auk would have a lot of pressure through the curves as it is pretty short and curvy shall we say.

Is that cutaway at the transom on your auk for a motor?

Dont take that as an insult if I am wrong. Don't want to offend any purists, but I havent decided what to do with mine yet. Row, sail, or motor?

Only real dilemma about the motor is any regulations about whether I need to register a boat to put a little 5horse on the back. I know there are regulations about flotation, build plates etc, but am not sure if it trickles all the way down to a 5hp.

The in laws in lakes entrance own these boats, and my little bloke is besotted with boats with motors (the third is him driving a little put-put in Merimbula.)

Bryan you havnt got a moaning chair have you?

I built a very large dining table about 5 years ago out of recycled redgum, and followed it up with chairs. THey came up a treat. I built 3 chairs to completion but three are still in the corner of the shed waiting on final finishing and cushioning. Probably about 8 hours work to complete and that would stop the chief of war and finance asking about them.

Do you think I could use one of those?