Sunday, February 15, 2015

Stuck together for good and decisions to be made.

During last week I made a new transom.  This time i cut the bevels on the timber before screwing and gluing to the plywood like Jim suggests in his book, and it all went much nicer.  I also cut the notches in everything for the interior wale.  I'd considered bringing this to the outside like the chine log, but it caused a number of other issues so I left it inside.  I glued and screwed those to the sides, and cut out all of the openings in the interior bulkheads.

Saturday afternoon I had a 1 hour window where my neighbor and his buddy could come by and help hold things as I glued and screwed it all together for good.  It was much harder benign the sides in accurately with that wale in place.  I can just imagine if I had the internal chine lots to deal with as well.  Mechanical advantage would have definitely been necessary.

That might have been a blessing in disguise.  I could have carefully checked all alignments as I slowly cranked everything in.  As it was, it was 3 guys grunting until "It's GOOD!  Shoot the screw!!!"  Still, everything hit the lines and sighting down the boat all of the bulkheads were parallel, so no twist.

This morning i got up, had breakfast, walked the dog and opened up the garage to take a good look at everything again.  Chopped off the spare stem above the wales and boat sides for a better sight line.  took the block planes and shaved the sides down flush with the wales.  Got down on one knee and took a good hard look.  Everything still parallel, Wonderful!  Uh oh....centerlines don't quite match up.  1/2 an hour of running the tape measure this way and that, and the verdict was in.  all of the bulkheads and the transom were parallel.  The stem is somehow @ 3/4" to port off centerline.  Now I could just delete this whole part of the blog, and no one would ever know but me.  Functionally, I might have a slightly faster boat on one tack than the other, but i doubt it will ever be noticeable.  Good news is the extra curvature is on the same side as the outboard mount is going to be, so maybe the combined asymmetry will make it motor straighter?  I think I'll just tell myself that.  It's not enough to make me chisel things apart and start over.  It's my first build, I'm using ACX Ply and PL premium.  It's supposed to be a learning experience.






I was asked in an email if I'd considered how to power the boat with an outboard.  The following was my response.


Graeme,

Thanks :-)

Yeah, that’s kind of my mental picture of sailing the boat too.  Especially after watching all the Youtube of Sean Mulligan’s Paradox videos down on Havasu.  In Jim’s original design brief he talked about how the sail was probably too big, and I’m seriously considering reducing the area.  I’l be sailing mostly on the Columbia River here in the PNW, and the topography gets the wind really howling a lot of days.  It essentially runs through a gorge from desert on the interior to the sea.  on a hot day, all that rock heats up sucking the wind in from the ocean.  One of the premiere windsurfing spots in the world is just 40-50 miles east of me at Hood River.  I wrote Jim and he thought @ 100ft2 would be appropriate.  I did a little research on paradox, and low and behold that nifty roller furling lug is right about 100ft2.  I’d love to be able to shorten the mast 2ft anyway.  It’s designed at 18ft, which requires scarfing.  I can find some pretty decent 16ft stock around here to glue up a mast from all day.  Lowering the effort would allow a little less permanent ballast helping the trailer weight.

I own a Potter 15 that has a main that’s only @ 65ft2.  Me , the girlfriend and the dog were out on a pretty mild wind day and moving just great under main alone, never even bothered to hoist the jib.  It’s the Potter that got me interested in the Robbsboat.  I got tired of having the centerboard trunk ruin the cabin in about 2 days flat.  I then realized that if the boat got swamped as high as the centerboard trunk, it was game over trying to get it bailed out.  The time it takes to rig the mast and sloop rig with the stays is irritating after my time spent with unstayed cat rigs on my little marbles trimaran.  Even the junk rig i built for the tri is a lot less hassle.  Lastly, one of the big discussions on Potters is how to get enough weight in the from of the boat because your weight is so far back in the cockpit.  Robbsboat cures ALL of these problems.  I almost forgot, it rains a lot around here, nice to be able to steer from a pilothouse :-)

Auxiliary power is big on my mind.  There’s usually @ 1.5 knots of current to deal with on the river.  Power is a necessity to make it home by Sunday night to make it to work on Monday.  I own a sweet little 2-straoke 2hp evinrude that a child can pick up.  Holds enough fuel to run about an hour though, and i don’t want to just strap gas cans on deck.  No way am I going to store fuel inside the boat.  I’ve been designing a fuel locker to go midships in front of the rudder.  It will drain out the transom and have a cover strong enough to stand on.  That way I can store gas and propane safely, hidden and out of the weather.  Still gotta do the stupid scissor bracket for the motor (Trust me, i though long and hard about a good transom cutout).  Jim designed a tiller that just comes through a cutout in the transom and protrudes slightly past the aft cabin bulkhead.  Due to the dimensions of the boat, it was going to have @ 30 degrees of sweep each side max.  Plenty for actual sailing.  My fuel locker forces me into a “T” head on the rudder and a rope linkage.  Easiest thing is to just go to a wheel and drum and run the rope linkage through the fuel locker.  If I run the locker all the way to the cabin bulkhead, I can mount the wheel on the cabin side, super short shaft into the fuel locker and the drum immediately abaft the bulkhead.  entire system easily accessible for inspection/maintenance/repair, and i just eliminated a major path for water into the boat.  I’d much prefer tiller steering, but this solves all of the problems.  The last issue is no good way to run a rudder downhaul, but I’ll probably just change over to a Mik Storer cassette rudder and call it a day. No lead to pour that way either. The transom is only 3ft behind the aft hatch, so both the rudder and the motor will be easily accessible without even getting my bottom half out of the cabin. 

I forgot to mention that it’s pretty necessary that i keep this locker midships.  I don’t want to lose the buoyancy at the sides for the knockdowns.  If I keep it no wider than 12”, It’s narrower than the hatch, so no loss at all unless I were to turn complete turtle.  Otherwise I could just offset the rudder, and mount the motor at the aft end of the fuel locker in a transom notch.  I’d still end up needing rope steering.

Reducing the sail area might allow me to shorten the boom enough that I keep the sheet clear of the motor as well.  I haven’t played with the CLR yet, but knocking the bottom 2ft off the sail Jim designed gets the mast length where I want it and makes it look a lot like the mayfly sail.  If i go to a standing lug like Paradox, that also helps allow me to shorten the boom and keep the balance.  I’d love to keep a balance lug though for the self vanging and to make Chuck Leinweber’s lazyjacks and jackstays work on the boat.


I should probably copy and paste this whole thing to the blog :-)

Tom


All of that being said, as i look at the rear of the boat and see just how simple it would be to build it to plan, I begging to wonder just how bad stopping a 3-gallon tank to the aft deck would be.  All of the extra framing and rudder linkage would be a pain in the butt, and i want to sail the boat this spring/summer.




As Jim has it designed, I make a small hole just under the framing timber through the transom for a straight tiller that protrudes into the cabin a bit.  I can run my up haul. a down haul if i don't want to pour lead and maybe even my mainsheet along the tiller.  I've got good enough access from beneath in the cabin that I can always make the change later if the fuel up on top bugs me too much.

Last thing I'm playing with is a tabernacle design.  going forward on this boat is going to be something that's not easy to do.  Some of the back sloughs that this boat is going to be so good for exploring have a lot of trees.  One of my favorite ramps has a big tree that prohibits launching right along the dock if you have a mast raised.  I love the thought of being able to raise or lower the mast with a yank on a rope in the cabin.  This would also alleviate any leakage in the foredeck from the mast penetration.  This I'm going to do for sure.  That's why I left the meat in the ply on the forward bulkhead. Tabernacle will be anchored all along it.

Next project is to get some more 1x2 and frame up the cabin sides for a little more support before i flip the boat to put the bottom on.  I should be ready for the flip in a few days, then next weekend will be bending those chines on.  weekend after that should be the first layer of bottom.

Good times :-) 

3 comments:

  1. I'd bet a tabernacle will increase your build time a good deal, and you'll need a winch or block and tackle to pull that long mast up with a short effort arm. I'd just stick to the plan on this. You just have to be willing to get your feet wet putting the mast up. (I rarely get underway without wet feet anyway.)

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  3. I have thought about the tabearnacle as the Twister I am building will be used not only on Central Illinois lakes and rivers but up in Chicago on the Chicago and Illinois River’s.
    Was the mast on the Robbsboat off centered like the Twister is?

    I know this is an old thread but a great read as i start my build!

    Cheers
    Wade

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