Thread: stitch and tape power boat

Just thought I'd throw a few more pictures up. Managed finally to get a chance to get more work done on the boat and glass the exterior. Next is to add the running strakes, bog and fair, then add the outside sheer plank and engine mounting clamps before painting the exterior.
Mark

G'day Everyone,
After a few months of sitting idle, (to much work) we finally managed to get out over the past few days and get a bit more down on our Mushulu 14.
Just a few more little bits and pieces to go on, then its time to paint.

In case your wondering, the cut-out in the transom is to suit a 20 inch outboard leg, so it gives you and idea of the freeboard of the boat
( you can cut out to suit for a 15 in leg if you want)

Overall, can't wait till it hits the water !!

I'll post more pictures soon

Regards
Mark

I really like the look of the timber when you glassed the underside of the boat.
Can someone explain to me what stitch and glue means? I noticed it a lot as well on the glen-l site.

Basically you cut bits of plywood to shape, stitch them together with copper wire, form a fillet of epoxy at the joints, cover both sides with fiberglass tape.

Generally, at least for smaller boats, it does not use stringers at the joints, the ply forms a structural skin so it's a "monocoque" structure. Sometimes cable ties or other things are substituted for the copper wire.

Some methods that really aren't what is commonly called stitch and glue:

You can build a series of frames and stringers and skin that structure with ply.

Joining along the keel and torturing the ply up and around to form a shallow double curvature in the ply. This is usually called (surprisingly) tortured ply.

A variation is where you make a uniform mould layer and glue veneer or thin ply over it to form a constant curve. This is either constant chamber or cylinder moulding.

Building up the shape with a series of strips edge glued together. Commonly called strip plank. Overlaying relatively narrow panels of ply at angles to one another, cold moulding.

And of course there are more.

G'day Everyone,
We don't advocate using wire for stitching. Wire has a very small surface area and when stitching the boat together, the wire can cut through the ply.

We prefer plastic ties. A larger surface area with greater "pulling" power. Also, the plastic ties can be left in after tabbing with no problems down the track.
Far Cheaper too

Other than that difference, it's basically how Damien decribed above
regards
Mark

Howdy,

What is used for stitching does depend a lot on the particular boat. We drew up the little Eureka canoe for Duckflat and they proved it out and set up kits using cable tie stitching.

The bigger Eureka, we planned to do this as well, but the cable ties just broke up in the ends - broke before they had enough tension in them to do the job - have had very little problem with copper ones tearing out of the edge of the ply. So we replaced them with wire.

So if you know a particular boat can use cable ties - that is great.

Best wishes
Michael

Originally Posted by damian

Basically you cut bits of plywood to shape, stitch them together with copper wire, form a fillet of epoxy at the joints, cover both sides with fiberglass tape.

Generally, at least for smaller boats, it does not use stringers at the joints, the ply forms a structural skin so it's a "monocoque" structure. Sometimes cable ties or other things are substituted for the copper wire.

Good description thanks. I also read up here which was helpful:
http://en.wikipedia.org/wiki/Stitch_and_glue

Plastic ties are available in different strengths depending on the application.

The cheap ones are crap & break easily,must have been what Mik used.

If you check the packaging or the manufacturer's specifications you can find the stongest ones,usually not the cheapest,but WAY stronger than the cheap crap.

In tight areas where there is a lot of tension on the ties,just use more,closer together to share the load rather than loading up just a few & have them fail or pull through if you are using copper wire.

These areas need local boiling water soaking ( steaming ?)of the ply with lots of soaked towels over the area being forced to take up a curved shape & be patient as it takes time to force ply to take up strong curves.

With some designs,especially at the bow, it may take many days of soaking & tightening of ties to get the ply to where you want it.At times you may think you're never going to get the ply to bend,but a reputable marine architect knows the characteristics of plywood & designs accordingly,so trust his plans & persist.

However, most modern s&g designs go together with little fuss. If you strike a problem, talk to the designer.

Al.

As regards cable ties, there is no substitute for Panduit and their brand-name competitors.
Made from nylon, not PVC.
You won't get them at a cheap-shop.
And they aren't cheap.
The UV resistant black ties are stronger than the white ones, but you have to try
hard to break even the skinny white ones.

It's not breaking them that's the problem, it's the little catch refusing to work. Still, that's just a case of tossing that tie and using another. I've done all my stitch and glue with cheap zip ties and didn't have any real problems (that's two Mouseboats and part of Redback).

Richard

G'day Everyone,
I managed to get back out to the boat this afternoon, sanding all that we glued in, then fitted the transom horizontal knees (or gussets) and cutting out the slot for the anchor rode and die grinding the anchor lid for the hatch lid lift ring.
Also over the past few days, I had been steam bending the breasthook over a mold to get the right camber deck curve , so it also was glued into position. (I was going to laminate a piece initially, but decided to let the sun do the work for me instead)
I then began to dry fit the clamp, shaping and cutting to suit, but ran out of time to finish the job. Hopefully tomorrow

Regards
Mark

We were issued a heap of cheap orangey ones one year for the Rough'n'Ready at
Goolwa about 10 years ago. Broke the first half a dozen. I realised then that they
were decorative rather than functional. Switched to copper wire so as to minimise
the number of ties needed to keep things intact whilst afloat. Swore at that time to
-never- waste my hard-earned shekels on imitation ties.

Good job with your boat Mark !!

cheers
AJ

G'day Everyone,
Here's a few more pictures taken today. All that's left now is a few coats of resin here and there, router a few bit's and pieces then time to bog and fair the interior .

Then it's time to paint!

Also, I thought I'd throw in a mug shot or two of myself sitting in the Mushulu 14 to give perspective on its size, freeboard and how large the seats are.
The outboard cut-out is suited for a 20 in or long leg outboard.

regards
Mark

bloody awesome mate thanks for sharing your time with us, its certinaly a great size and good looking boat