Prototype build of ELLIE

[Paul TParticipant @pault84577]

Here is a view of the completed hull

This shows how the bow design looks and should help explain why the frames have been causing so much discussion.

Paul

 

 

 

Edited By Paul T on 05/08/2013 20:03:28

[Bob Abell 2Participant @bobabell2]

Many thanks Paul

You seem to have covered every possibility!

Nice to see you back on the thread again, Matey

I have been tickling up the formers here and there, today, but it is difficult deciding what the straight edge is trying to tell me! Any angular deviation and things go haywire!

The hull shape is certainly an unusual shape!

It should be very amusing seeing the forum members own interpretations of the hull shape?

Bob

[Paul TParticipant @pault84577]

Bob and I have been discussing the various ways to form the stringers around the fairly tight curve of the bows and I think it might help everyone to see an example of one method.

The images are from a different project but they demonstrate the method.

A series of 4.5mm deep cuts at 5mm spacing to the inside face of the stringer will remove sufficient material to allow a tight curve to be formed.

A little patience and attention to detail is needed whilst cutting the notches to avoid cutting right through, to avoid this I made a little jig which stopped the saw blade at the correct depth and I cut by hand with a junior hacksaw.

After the cuts are made the 6 x 6mm stripwood bends very easily and it becomes a simple matter to fill the notches with glue and fix the stringer into position.

Paul

[Bob Abell 2Participant @bobabell2]

Morning Capt

That's a very neat way of getting round a tight bend!

I'm hoping to make a temporary plywood inner former to prevent over bending the shape, for Stringer B

Noting that half the stringer is planed away from Former 2 to Former 1 and could break into the bend notches?…….May need a doubler as a back up, before planing to shape?

Going to glue the spine to the keel this morning, to make the structure more rigid for adjusting the formers

Is there any chance of doing an iso of the bows section, showing the lie of the sheeting?

Bob

[Paul TParticipant @pault84577]

Hello Bob

Will this do?

Paul

[Ian GardnerParticipant @iangardner62867]

I'm enjoying following this but have been dying to ask, why you don't just use a solid breasthook forward of the first bulkhead which would save all this bending of stringers. A similar piece could be used at the chine line as well- it's what I have always done when building a hard chine hull. The stringers are then just notched into the aft end of the breasthook. Perhaps I have missed a vital piece of the discussion, and if I have – my apologies!

On a separate note- just been out to buy a sheet (4'x1&#39 of 0.8mm ply……ouch!

All the best,

Ian

Edited By Ian Gardner on 06/08/2013 13:15:36

Edited By Ian Gardner on 06/08/2013 13:16:26

[Bob Abell 2Participant @bobabell2]

Thank you, Paul

That looks harmless now?

How about the build up at the prow?…..With the keel and hull sides coming to a point etc

Ian

What's a Breast Hook?……Sounds fascinating?

Bob

[Dave MilbournParticipant @davemilbourn48782]

Never mind the spelling – this is a breast hook. I suspect that Paul's chine line has an upward curve in it ahead of the second former. This would mean putting a curve into a piece of 1/4" ply……..be my guest!

Dave M

[Bob Abell 2Participant @bobabell2]

Thank you, Dave

I'm still none the wiser!

They say a picture speaks a thousand words…….It ain't worked this time?

What is a Breast Hook?

Bob

[Bob Abell 2Participant @bobabell2]

Thank you, Dave

I'm still none the wiser!

They say a picture speaks a thousand words…….It ain't worked this time?

What is a Breast Hook?

Bob

[Ian GardnerParticipant @iangardner62867]

I was thinking of your picture of a 'brest hook' Dave, so thanks.

Bob, its the solid piece which forms the curve in plan view, into which the stringers are notched in Dave's photo, taking the place of curved stringers. There would probably be a similar piece at the chine level too, giving a solid surface for the skins to land on. I reckon lots of the old kits and many drawings of hard chine hulls that I have seen would employ this method. As for any upward curve- I reckon it could be got round one way or another- make 'em out of balsa!

I just wondered. The same sort of thing is often used on full sized dinghy building.

Don't mind me- carry on.

Ian

[Ian GardnerParticipant @iangardner62867]

Same idea on my Rapier build- Dave's photo is clearer though. Looking at it again, it wasn't even necessary here.

Ian

Edited By Ian Gardner on 06/08/2013 15:26:29

[Paul TParticipant @pault84577]

Breasthook is the curved piece at the top of the stem post that joins the stringers together it also increases the strength of the boat at this critical point.

Dave is correct in surmising that my design has an upward curve toward the bow, this upward curve is one of the reasons behind the spacing and positioning of frames 1 & 2. In my design the foredeck and frame 1 do a double duty as breasthook.

Paul

 

Edited By Paul T on 06/08/2013 15:43:39

[Bob Abell 2Participant @bobabell2]

Thanks Dave and Ian

We were having a solid block of wood about a week ago, but we`ve got round that now

The name…."Breast Hook"………..is a strange name?

What`s up with……"Block of wood"………..As fitted by a "Sagger Bottom knockers mate"

Bet yet cher, you don`t remember that name?……….Here`s a clue…….."What`s my line"

Gilbert Harding….Barbara Kelly…..etc

Bob from the olden days

[Ian GardnerParticipant @iangardner62867]

Like all specialist nomenclature, you know exactly where you are- block of wood in this context would need all sorts of qualification. Anyway, an interesting diversion- and at least we all know what a breasthook is now! And how to spell it!!

Keep up the good work … Ian

Edited By Ian Gardner on 06/08/2013 16:57:36

[Bob Abell 2Participant @bobabell2]

Hello chaps…..,

Paul has got a full length deck of thin ply and that surely can go concave at the Breast Hook?

Can't understand why Dave is talking about 6mm ply?

Bob

[Dave MilbournParticipant @davemilbourn48782]

Bob

Don't worry your pretty head about it.

Dave

[Paul TParticipant @pault84577]

Dave has raised a very good point regarding design / construction and a builders expectations of how a model goes together. This has kept me awake for most of the night as I considered this point in relation to my design.

To explain… If you look at the image of Dave's recent sea nymph build you will see a typical example of a kit build where the manufacturer has designed out the more complicated curves, the deck level stringers stop short of the bow and the whole bow/foredeck structure and shape is predetermined by the introduction of the large breasthook.

My design is far more complex around this area and whilst an experienced builder should be able to understand the method of construction a beginner would struggle.

I am still thinking about this and awaiting Bobs comments as he completes the construction of the frame.

btw Daves 1/4 ply comment refers to the chine stringers [ these form the joint between the bottom and upright sides of the hull ] where they sweep upwards from frame 2 and the substitution or addition of horizontal breasthook type feature at this point.

Paul

[Bob Abell 2Participant @bobabell2]

For Dave

Bob

[Bob Abell 2Participant @bobabell2]

Shop floor here again, Surrey!

This is the glued keel and former assembly………It`s lovely and solid!

But got some former discrepancies, towards the back end, about + or – 1mm

Could be my shoddy workmanship of course, but I`ve asked Paul to check the formers

With CAD it`s practically impossible to get the dims wrong, but with this Ship type CAD, and New Age hull shape……..it may be possible?

Looking aft, notice the last three formers are not following the trend of the forward end formers. I could easily adjust to suit, but they need to be correct for the new builders

I normally stack the formers, prior to assembly, and any errors would have shown up, but this time, I glued the feet on!….Doh!

Note the formers in the foreground were modified after the first drawing issue

 

Here`s another view…..

Former 6 is the Scallywag!……and I`ve already sanded a miili off!……..Also slightly doctored a few more, by a midges

Shopfloor co-ordinator

Edited By Bob Abell on 07/08/2013 10:07:56

[Paul TParticipant @pault84577]

Dear Shop floor coordinator

I wouldn't worry too much about a +/- 1mm as this is less than the thickness of a bandsaw blade, the design has some built in tolerance to allow for minor discrepancies of 1mm or less.

Any serious problems will show up when the stringers are fitted.

Paul

[Bob Abell 2Participant @bobabell2]

Shop floor to Mr T

Can`t imagine what a "built in tolerance" is, but it sounds ok to me!

Glued the first two stringers in position and are well within the built in tolerance!

I take it, the Breast Hook idea has gone by the board?

Tried a piece of 1/8" ply at the bow end bend, but it didn`t like it, but 1,6mm seemed to be feasible

Bob

[Paul TParticipant @pault84577]

Bob

Looking good.

To include a breasthook would over complicate the existing design and would require a complete redraw of the hull from frame 2 to the bow.

Built in tolerance means that an allowance has been made within the design to compensate for wonkey cutting or slightly off square glueing.

Paul

 

Edited By Paul T on 07/08/2013 18:34:50

[Bob Abell 2Participant @bobabell2]

Workshop report…..

Stringer B has worked out quite nicely

Using Paul`s "back sawn stringer" idea, which he cribbed from his Stradivarius violin…….I`ve managed to make the full bend from one full length stringer!

Using sawcuts every 6mm, the stringer becomes very flexible, but needs great care once cut, as the wood strip is quite delicate

Note the use of the "S" hooks

The nose block had to be removed. Suggest the keel nose to be extended and a foot fitted similar to the formers

Bob

[Tony HadleyParticipant @tonyhadley]

What timber are the stringers made from and what is the square section size of this wood?

Tony

[Author]

Posts