Building Shesha, a Hunter Valley GIS, Australia

[woodeneye]

My confidence took a real beating today as I struggled to come to terms with the notches on bulkheads 1 & 2. I thought I had them measured right, but the angles don't seem right. Trouble is I don't know where the bulkheads are meant to sit relative to the bottom of the chine log. I guess the height of the bulkhead is important so I'm trying to get this right. I think Bob and others had this problem too but it only revealed itself during the assembly, and there was a gap between the BH and the bottom panel.

My troubles may have stemmed from measuring the cuts for the chine log AFTER I made the side bevels. This could have changed the placement of the lines I measured. But then the instructions do say to make the bevels before going on to mention the notches for the chine logs.

To try and solve the mess I've got myself into, I laid out a side panel which have the chine logs attached. Ignoring the frame, the bottom ply edge of the BH is about 5mm from the bottom edge of the chine log. Should I trim the notches to bring the BH's bottom ply edge down to the edge of the chine log? I'm not sure which edges need to match up with each other. Is it the ply edge or the frame edge?

I'm also worried that the bevelled edge of the bottoms of the BHs are not parallel to the edge of the of the chine log, but I'm going to ignore that for now as perhaps this all gets pulled into line during assembly?

Would it be helpful to have a measurement referencing the top edge of the bulkhead to the top of the sheer at each point? I don't know if it's relevant or not....

Heeelp!

[woodeneye]

There's nothing like sleeping on a problem I must have been really tired and not thinking straight late last night. Something to remember...get to bed and have a rest, or a beer or whatever! ......As Effie would say, "How embarrassment?!" (Aussies will know what I'm talking about)

This morning it was all clear to me and the problem of how to fix it is a small one. I've simply epoxied the chine-log cut-out back into BH1 and I'll recut it when it cures. All the other BH's are done and they seem to fit well on the chine-logs, so barring any unforeseen dramas with the assembly everything should be OK with the bulkheads.

[Boatmik]

Small misalignments are of little consequence. The trickiest ones are the first two because small differences in the bevel can make a bit of difference. However there is nothing we have not been able to fix - there is enough flexibility in what happens later to make any problems disappear.

MIK

[CCBB]

I had a chine log scarf create a very flat spot in my chine on the stbd side so much so that it pulled one bulkhead off by 1/4". The bottom pulled it all together back to centerline and the flat spot is largely pushed back out to fairness.

[woodeneye]

Comforting to know guys, thanks!

Latest progress: Oztayls-Building Shesha, a Goat Island Skiff

[MiddleAgesMan]

I don't know how much good it did but when I was gluing on the chine logs I induced a little bit of curvature in the sides by propping up the ends a couple inches. When dry they held this slight curve so at least I wasn't bending against the natural lay of things.

[Boatmik]

Howdy,

Clint is showing how even if things go wrong you can still recover just fine - particularly if you sort it out with a dry run first.

Almost every one of my pointy nosed boats ends up being very fair indeed - part of this is the result of the effort involved in bending the side panels into place. If the timber bends reasonably fair then the sides will automatically be very fair too.

Clint got stuck with some timber that changed shape quite a bit over a few days so that it never ran very fair even off the boat.

However with a dry run it is possible - even easy - to pull the whole thing straight up the centreline (nothing special - just follow the plan procedure) Pin down the bulkhead end and then just push the hull into a fair shape putting screws through the bottom into the chine log as you go.

It is better of course if the chine log timber runs pretty straight.

Best wishes
Michael

[woodeneye]

All is well now, but I had a couple of setbacks very early today.

Only yesterday I was saying to my brother how good my old Bosch sanding machine was. Well, I thought I'd give the frames a sand before installing them as it's easier now than later. As soon as I turned the sander on, there was trouble...it was only running at 1/2 speed and there was none of the arm wrenching torque that I’m used to. I stripped it down thinking it was just clogged with epoxy dust, but sadly the motor or the bearings were seized. I've had this thing for 20 years, "Made in Switzerland", so I knew that its replacement was going to be made in China.

Off I went to Bunnings. The new Bosch and everything else that looked any good were ALL made in China. NOTHING operated at 24000rpm like the old machine, and the best of the them speed wise was the 250w Bosch at 12,000rpm. However, the Makita (11,000rpm and 250w) had better features than the new Bosch, like better paper grip mechanism and side dust extraction ports rather than through the paper. (My old Bosch had side ports so dunno why they've taken a backward step with "through the paper" extraction, which means it needs holes in the paper.)

And so I walked out with a Makita 1/3rd sheet sander. It's OK, and sucks up the dust very well, but I just knew it was going to be slower than the old Bosch, and it is. It is very smooth and quiet and gets the job done, but I miss the shear performance of the old Swiss made Bosch screamer that you had to really hang onto!

That episode set me back all of 3 hours.

My other problem was during the dry fit. The Paulownia bow stem just couldn't hold the middle screw while I was fitting BH1, and it popped open under the load. Luckily it was a dry fit run, so I've elected to glue up the stem and let it cure overnight under screws and clamps without stressing the joint. This will be nice and strong in the morning for a tilt at assembling the sides and frames. I will just proceed with a glue up and won’t do a a dry run first. Then I'll join the bottom halves for installation during the week.

Here are some pics of it as it is at present, with the stem curing... The $10 ceiling prop comes in handy as a spreader. It will have some mighty work to do tomorrow, as the sheer has to be spread and the chines pulled in. The sacrificial 3ply that protected the Okoume plywood makes a useful temporary floor!
Attachment 131472


Below is a shot of the stem. Yes it tapers from top to bottom and therefore the angle changes down its length, which imparts "twist" to the sides, hence the usefulness of the spreader bar. The pic above shows the stem taper quite clearly. You can just see the clamp and the offcut wedges that are taking the pressure off the screws. despite the screw pulling through, I'm not worried about the Paulownia stem being strong enough. There is plenty of glued surface area there to take the forces that will be applied tomorrow. The bow will also get a hardwood cap which will provide further integrity to the joint.
Attachment 131473

Big day tomorrow!

[MiddleAgesMan]

Gluing up the stem-side assembly before stressing it is the way to go. I think mine cured two days before I was willing to test it but my 'pox and conditions were likely different from yours.

Your chine logs at the stem appear to be better fit than mine but it looks like there are small gaps. Being a worry wart I borrowed a trick from canoe builders--raised up the aft end and poured in several ounces of 'pox mixed with microballoons. The microballoons were a concession to MIK's advice to "add nothing extra."

This was done AFTER the bottom was in place, of course.

[woodeneye]

Gluing up the stem-side assembly before stressing it is the way to go. I think mine cured two days before I was willing to test it but my 'pox and conditions were likely different from yours.

Your chine logs at the stem appear to be better fit than mine but it looks like there are small gaps. Being a worry wart I borrowed a trick from canoe builders--raised up the aft end and poured in several ounces of 'pox mixed with microballoons. The microballoons were a concession to MIK's advice to "add nothing extra."

This was done AFTER the bottom was in place, of course.

Yes, the chine logs a quick adjustment during the bow fit-up. I should have taken some more time with it, but it won't be seen. It will need a goodly blob of poxy filler in there after the bottom goes on. So far, that's the biggest gap I've made!

[Boatmik]

That is a good point about the paulownia and the stem - I would be tempted to put a temporary bolt through the bottom of the stem until the bottom goes on. Once that happens there are no significant loads.

Put ply pads under the bolt head and nut.

Or you could use a long drywall plasterboard screw that goes into a block of timber on the far side and has a ply pad under the head.

Best wishes
Michael.

[woodeneye]

The stem is fine Mick, but I understand your thinking. The bolt through the bottom would have been a necessity if assembling before the epoxy has fully cured. An excellent tip

[woodeneye]

Birth of another Goat Island Skiff


Attachment 131635 I did a dry fit of the bulkhead and transom and discovered for myself what I’d learned on Michael Storer’s Woodwork forum, that a second pair of hands are really useful! Unfortunately, Kim works on most weekends (she’s a Registered Nurse) so a different way of thinking for a single handed assembly. It is only necessary to pull in the chine (the hard bit!) and the rest just comes along by itself. As you can see, using two clamps and a piece of rope does the job easily. In this pic I have not yet screwed bulkhead #1 in position as it is firmly held. This makes it easy to tap the BH into position and insert the screws.

There is a LOT of force on the first two bulkheads, which for the dry fit were only fixed with two screws per side. I did not want to unleash all that force by undoing the rope and risk stripping the screws, so I had another trick which worked a treat, and allowed me to undo the rope and move to fitting BH2.

Here it is.

Attachment 131636 Just a couple of wedges screwed into the trestle on each side to prevent the chines from spreading. It worked a treat.

Attachment 131637 Using this method, I just worked my way back to the transom, dry fitting the bulkheads.

Attachment 131638 You can see the low trestles I made to support the hull off the ground. It helps with inserting the screws and operating the clamps. They are only about 12” high.

It was just as well I did a dry fit, as I found myself out with 2 errors! The first was that I’d bevelled BH4 the wrong way! How I managed to do that is still a mystery to me, but it happened. Anyway, I marked the bevel and had it sorted quite quickly with the block plane. The second wasn’t so much an error as a tweak, with the transom side bevels needing adjustment. I do recommend doing a dry fit as it gives you the opportunity to get such things sorted without the pressure of an epoxy mix going off!

Attachment 131639 Well, after the dry fit, the glue up for real was a doddle and went without a hitch. Pretty boring hey? I bet you were wanting to read about a drama or two, which would have spiced things up a bit, but no, it went pretty well. After BH1, I did change from using Phillips head drywall screws to square drive screws. The square drive screws are so much easier to use than phillips head and the bit won’t jump out of the head when the real pressure is applied while you hold a BH with one hand and screw with the other.

Well, I must admit to a small panic when I came to measuring the boat for squareness. Measuring from BH3 to the opposite corner of the transom, it was off by some 75mm! Holy crap, that was a huge amount!! But folks, the hull is pretty flexible in this state and after figuring out what was going on (the alignment of the bulkheads gives you a clue when you sight down the tops of them), a few pushes and pulls had it sitting square. In the last pic you can see the yellow cord which is tensioning the diagonal. Installing the bottom will give me another opportunity to square things up if there is any spring back.

The last thing done before shutting up shop at beer o’clock was to clamp on the Hoop Pine sheer strake. This helps to fair the lines while the epoxy sets up. By the way, the car batteries are there to pride some weight so I could drive the screws without the boat skating away from me.

I was quite happy with how things went. All up, the dry fit, corrections and glue up assembly took me 7 hours, which I thought was reasonable for a single-handed effort.

A walk around the hull confirms one thing, that this is another GIS! The relief that this part of the build is now done, is considerable.

Guess what else, I’m feeling pretty good too

[MiddleAgesMan]

Working without assistance is my preferred way when doing this sort of thing. It forces you to find the best tools and techniques and relieves you from the worries of having a helper who may not follow directions or one who hasn't mastered the use of his opposable thumbs.

[BobWes]

Great work!

You certainly ought to feel good after bringing Shesha to life. I'm glad it went so well for you.

What was Kim's reaction? When she went to work you had a collection of parts. When she came home you had a boat!