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building Autumn Leaves
#1
Yesterday I made the first cut on my Autumn Leaves build.  I have most of the plywood to finish the boat on hand and should be able to get pretty far with it.  I am building this boat out of the same materials that I built Duckie out of except that most of the ply is 3/8 instead of 1/2.  I have already deviated from the plan in my first day.  Instead of laminating the bilge boards out of two pieces of 3/8 ply, I used one piece of 3/4 MDO.  I saved a bunch of epoxy this way.  I made the boards first because I have to fit them inside the trunks and I want to have them to mess around with.  For now I will be cutting out bulkheads and assembling the central core, ie cabin. 

When I get a little further, I will take some pics. 

Al
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#2
Exciting! It's a cool plan , too bad there were no interior renderings on the site
Look forward to the pics. I've never seen MDO used in boats but it looks like a natural choice
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#3
I used MDO for all the 1/2 inch pieces on my weekender build.  It is cheaper than fir marine ply while still being made from the same stuff.  Paul advised me to do away with the resin covering at all the glue joints, so I used a block plane to scrape the resin away from the glue surfaces.  I think he was right.  So far the epoxy glass covering is sticking fine, so I have no qualms about using it again.  The bilge boards are the only 3/4 inch pieces on Autumn Leaves, and it took a full sheet to make them. 

Because this is a speculative plan, no one has built one before.  Therefore, I have to be suspicious of all of the written measurements.  I have already found a couple numbers that don't give a fair curve.  I took the precaution to draw out on a piece of pressed wood the pertinent part of the sides to check that the trunks will fit properly.  That took a good bit of time yesterday.  I hope to have the cabin core assembled dry by the weekend.  Once Duckworks is up and running, I will order the glass, epoxy and carbon I need to finish the interior of the trunks. 

Al
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#4
All plans will have errors and more importantly dimensions that are "close enough". Most designs take dimensions down to an 1/8" (3 mm) which is a pretty big gap. I take them down to a 1/16" (1.5 mm), but even at this, some fairing of the edges and shapes will be necessary. This is one reason We use battens to "connect the dots", so we can see slight irregularities and unfairness. Moving a point or two around, so the batten takes a "sweet" fair curve is the key to a good looking project. The first time you do a lapstrake line off, this becomes really apparent. A lapstrake I did last year took only a few hours to erect the station molds, but about a dozen to get fair plank seam runs during the line off, as I moved the battens around, some just a pencil line thickness, to remove humps and hollows along the edges of the laps. Lapstrakes are all about the planking lap curves, which just have to be sweet, or it looks like crap.

The first image is the station molds getting stood up, which didn't take long. The next image is starting the line off process, which as you can see has some uneven and unfair "runs" in the battens. The last image shows where I decided to let the laps live and though I can see places I wish I'd done a better job, most think it's "fair enough".

All curves need to be sorted by eye, because this is the true governor, in spite of what the plans might say.


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#5
Exactly. 

Every curved line that I make I check by eye and make adjustments accordingly.  I expect that this will  be true all the way through the assembly.  My weekender didn't fit exactly for some unknown reason, but it came out okay anyway.  I expect the same will happen here, though I am going to try to keep to the plan just to see if I can do it.

Al
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#6
If the parts are CNC cut and the cut files and drawings, have been test assembled before finalized, they should have perfect fits. This isn't always the case, as fine tuning mock up panels to remove a 1/16" variance is costly, but on bigger, more popular kits, they usually get this fine tuning. Hand cutting (even with power tools) introduces subtle inconsistencies, which cause these odd variances, so all curves need to be checked by eye, which is more precise than any machine, amazingly enough. Most don't realize how good their eyes actually are. You can see a lit candle from a mile away, try that with a digital camera. You can also see a 3 thousandths of an inch (.08 mm) pinhole in a black piece of cardboard, which about the diameter of a human hair. Your eye is far superior to most equipment. If you take a part to a machine shop, they only guarantee a .003" tolerance, without special tolling. Many machine shops don't even guarantee this. You eye can see the most imperceptible deviance in a curve, trust them, they're really good.
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#7
Well, I've  been at it for about a month now so I figure it is time for a report.  So far I have been able to assemble all of the bulkheads with some set backs.  For instance, some of the clear straight grained lumber I bought for stringers was so case hardened that it pulled one of the bilge board trunks out of whack so badly that I couldn't straighten it out.  I had to toss the whole thing and start over.  That turned out to be a blessing in disguise.  I checked with my cute little neighborhood lumber yard and he had straight grained and clear, quarter sawn one by six doug fir on hand.  I bought a hundred dollars worth with the assurance that he could get me all I wanted.  It's pretty nice stuff. 

I also had a mishap with one of the completed bulkheads.  I dropped it and it broke into four pieces.  That woke me up to the notion that I should make the reinforcement along the edges a good bit more substantial than the plan called for.  Because the bulkheads are only 3/8 ply, the edges all the way around are reinforced with one X three quarter.  That isn't enough on some of the more heavily beveled sides, or where the bulkhead is cut down to a mere couple of inches.  These vertical edges of all the bulkheads are quite a challenge.  Two stringers run the length of the sides in a straight line and must pass through the bulkheads.  To do that the bulkheads must be notched out at just the correct spot to allow the stringers which support the floor and bed/shelving/seats to pass.  It took me a while to figure out that fat pencil lines would be my undoing, so I bought a few mechanical pencils and a couple nice rulers.  Also, my trusty sheet rock square is getting a pretty good workout.  I baby this tool because it is so useful, and I want to make sure that it is exactly true.  I constantly check it to make sure it is not off. 

I have dry fitted the cabin/core a couple times.  Getting this part right is critical.  I have figured out a way to use the cradle that I built Duckie on to give me a straight square and true base to glue this part up.  I hope to finish glassing the trunks and finish up the pivot setup soon so that I can glue the core together and get on with the sides.  I have figured out a way to vent the sealed chamber on the outboard side of the trunks.  I went to Menards yesterday and found that a schedule 40 pvc coupler with a threaded cap on one end will do the job quite nicely. 

I must drill out the holes that the pivot pin rests in to about an inch or more diameter then backfill it with epoxy so that I can drill it out to accommodate the pin and protect the wood that will be underwater.  If I can find some brass tubing, I will line the hole with it because I plan to use brass rod for the pin.  Those boards better work miracles,  because this is a lot of monkeying around. 

So far, this project has made me step up my game just as all the other boat builds I have done have, so it is having the desired effect.  I only work a short time each day but at the end of the day, I am satisfied, so I can't think of anything I would rather do right now.

Al
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#8
Al, when making bushings, like for your board pivot pin, I like to counter sink each side as it exits the material. The idea is an additional bearing area under a washer or bolt head, to prevent crushing, from torsional loading. Also instead of a bronze tube, I've had much better success with UHMPE, which is a much tougher version of HDPE (the stuff cutting boards are made from). The nice thing about these plastics is they're self lubricating, tough as sin and inert, so no corrosion. I put a UHMPE bushing (still inside an epoxy bushing) on my Ketch about 10 years ago and happened to pull it this summer to fix some leading edge dings. The pivot pin hammered right out, no problem (self lubricating thing) and though a very slight amount of distortion could be seen (hole slightly egg shaped), it was very reusable. The leading edge repaired and everything reused, board, pin and bushing. I wouldn't even consider brass, as it's very weak and corrodes badly in brackish and salt water, not as quickly in fresh, but still . . .
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#9
Thanks Paul, I will look into it.  I have used different plastics in a lot of outdoor projects and like working with it quite a bit. 

Al
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#10
This is a test.


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