Shaping the daggerboard rudder design dilemma

Today and yesterday I spend predominantly tackling my nemesis, the daggerboard and its subsequent shaping.  For some reason I have held a slight amount of apprehensiveness towards working the rudder and the daggerboard, I dont know why, but I get the sneaky suspicion that they dont like me, and I dont like them, and were going to fight.  Meanwhile, my Goat Island Skiff languishes in the garage waiting for a rudder, waiting for gudgeons, waiting for the rear seat to be glued down, etc etc etc, as I suspiciously eye the squared off blanks that will be my blades.  See the previous post to view the blanks.

A disclaimer:  You will notice SUN in these pics.  The garage doors are OPEN for the first time months!  It hit 50 F. deg. here at the homestead, the first time in months and months.  I worked without a hat or jacket!  It was nice indeed.  

First, using the template included in the plans I kind of traced the shape of the foil onto the blank.  I roughed it, because I would use the template later to match the shape correctly.  Then, the first pass on the plane down the trailing edge side... and away we went.  Remember that the trailing and leading edges are cherry, a hardwood.  I sharpened my planes before this project and also during when I would swap sides.  It made my life much, much easier.

 

As time progressed, I slowly worked inward, taking off the wood and feeling the idea of the shape rather than mechanically proceeding.  Its kind of difficult to explain, but I knew the shape I was going for and went for it, with checks to the rough outline to keep me true.

 

As the planing progress, I would check my jig for appropriate foil shape.  Here, I have achieved the desired shape, OOF!

 

Now, I will be the first to tell you that the entire blade doesnt necessarily have this nice of a fit the entire time.  It is, however, close enough for this amateur! We all build to our own goals.  The foil shape I got is very even, nice, and for all purposes close enough without whacking out a giant mistake and having to start over... something I definitely do not want to do since the cedar in these blanks cost me a pretty penny indeed.

The blades were notched on the trailing edge per the plans.  On retrospect,  I could have probably left them how they were because it just made for a more complicated shaping project.  I wanted to keep the shape of the foil through the transition to the end of the blade, and therefor got this kind of neat compound curve (see below).  It worked, but it almost didnt, and for a few moments I thought I had taken off too much and really screwed myself.  Also, this is a good spot to let the reader know about the trailing edge width.  Its supposed to be squared off, but I didnt know how wide.  A quick journey over to my compatriot in CA gave me the answer.  He had finished his blade to 3/8", mine was 1/4".  Apparently, its supposed to go to about 1-2mm, or a 1/16".  HA HA HA  Sorry, I got mine down to 1/8" and Im very very pleased with that.  Again, I dont want to risk breaking through the back of the board, Im looking for durability, and the alignment of the centerboard trunk with the hull will make more difference than the 1/8" Im off.  Im not saying you cant go to 1/16", I just didnt want to.

The leading edge was next.  I took off a 45 deg. edge first, and then added subsequent degrees from there, until I got a nice rounded leading edge.  It worked out very well, and with a sharp plane, the work was precise and enjoyable.

 

I still have to sand everything down, cut off the top, and get things nice and smooth, but the blank is now shaped and I have a daggerboard worthy of some sort of aero-hydro-dynamic performance.  Its not perfect, but Im happy with it.

 

Next up is the rudder.  This is important because Im waiting on several other issues until I finish the rudder.  First and foremost is answering the question if Im going to go with Storers design on the rudderbox.  I am not a fan of it.  First:  The rudder is never permanently attached to it, it slides up and down the box with no rear, bungee cords hold it in place  I dont like bungee cords, the degrade in UV and salt, and Im not interested in having to replace parts like this.  Second and most importantly, the box and the tiller are permanently attached, which means I cant remove the tiller without removing the rudder and the box from the transom (now I have to put them somewhere-- think sleeping aboard).  I could design some sort of device that folds the tiller up, but then it gets in the way of a theoretical boom tent or something else, or it comes crashing down in the middle of the night on my head.  No thanks.  Give me a tiller that dismounts from the box, so I can throw it on the floor.  Third, with a permanently attached tiller-to-box, I will either have to enlarge the hole in the transom to use the pintles and gudgeons I want to use, or use Storers suggestion which is two gudgeons on top of each other with a pin running between all them.  I have spent more than enough time struggling with rudders and bizarre attachments that I know, in waves, with current, with wind, its going to be a total pain in the ass trying to thread a needle through a million holes (of course the rudder wouldnt be attached which might make it easier).

Anyway, call me a curmudgeon, but Im not a fan of the back-less, bungee cord, permanent tiller design.  I may have to come up with something else.

Rudder stock design rudder 2 daggerboard shaping

WELL

Informative day today as I peddled my rudder stock idea over at Mr. Storers forum.

There was enough persuasion action going to keep me going with the plans in term of a backless rudder stock with a daggerboard rudder.  However, I really want to be able to ditch the tiller and leave the rudder installed on the transom.

I came up with this idea:

In this plan, the rudder stock stays exactly as the plans stipulate, except I add on 15mm at the top.  This provides an area to attach a cleat (blue).  Then theres another below it (blue) and the tiller-- which is two pieced-- cradles the rudder stock.  Bolts run through the cleats into the spacer, and the tiller which slides between the cleats is held in place with a pin.

Storer warns that the torsional forces on the tiller could tear it apart, Im hoping that between the three cleats bolted through the spacer, and a bolt higher up on the tiller (not shown) to keep it together, I should be ok.  Time will tell.  I am almost positive this is the model Im going with, unless I get overwhelming evidence otherwise.

In other news, I finished rough shaping the rudder and daggerboard. 

Nice.

Bottom trimmed centerboard trunk and bat house!

Today was a productive day, the boat went upside down and back again.



My friend Peter ambled over with his router. This, combined with a flush-trim bit for the router, is a fabulous tool at dissolving the extra overlap left over from the over-sized bottom. It was either going to be a hackfest at sawing/planing it off, or this. The router was mucho easy to use, I cleaned up the enter boat in mere minutes. It left a little lip, which was cleaned up by my handplanes. Long strokes parallel to the boat to get it close, and then the smaller block plane held at an angle to the hull to get it finally flush. This took longer but was enjoyable work. The boat got dropped once, and it was not any worse for the wear.

The centerboard trunk components are also all glued up, but in two pieces. They will not be glued together until the daggerboard is complete, and then I can appropriately take the down the spacers inside (made from daggerboard jetsam, hence same width pre-finishing) to match the daggerboard, plus 2mm for a cozy fit. The daggerboard is being worked on on the side... I think I have a tempestuous relationship with the board and Im taking it slowly.


Peter, while he was over, made a three chambered bat house for his own house. Hes hoping to attract a small colony of bats to summer with him in his moist woods. One brown bat will eat 500-1000 mosquitoes an hour (yes, read that again) and a large bat house could contain tens upon tens of bats if not well over a hundred. Thats a lot of mosquitoes that are going to bite the dust. Additionally, bats eat truckloads of insects that attack farmed crops, help in seed dispersal and some species can be key in plant pollination. Bats do not equal gross, bats equal important. In New England (and spreading south!) we are afflicted with "White nose syndrome" which is hacking away at our bat population. The more bats we get, the better off we all are.

Each chamber is 3/4 of an inch. There will be a plastic grated landing zone below the chambers. The box will be painted a dark brown, and affixed on his house. They like it hot, and hot it will get. Bring on the bats!