Friday, 5 October 2018

A Bit of Progress.

Ok, I think I just recovered the way in to the old vmss website blog. The crash of my previous computer caused a great deal of grief and the last few days have been a major frustration as I found my way back.

Anyway, I have a bit of progress to show both on Althea, my A class Highlander design, and on the next build, just started on a Fort or Park ship.

Here's some pictures:-
 This one is Althea with my grandkids to show the scale and because they're cute.

 This shows both the hull and its detachable keel on the stand to the left.  That's 40 lbs of lead and a bit of cedar.  Both of these have been epoxied and rubbed down, and epoxied and rubbed down, and e-----------, to the point of nausea, but they have at last received their first two coats of varnish, the finish shows in the sun as I wanted.  There'll be several more coats of varnish to go, but the next work is the deck fittings, rudder, and rigging.

Then there is Althea's hull next to the very beginning of the Fort or Park ship build. That's clumsy but I don't yet know which of the ships built in Victoria I am going to name it.

I am going to try to build this next ship using the old bread and butter technique for the bow and the stern, and then the centre is essentially a straight box that I can just put in 1/8 inch plywood.

 I took the original cross-section drawing and re-measured the waterlines at 3/4 inch to produce the waterline drawing on the right.

 I have yellow cedar planking at 3/4 inch thick and so can bandsaw the  sections you see here.  I have a profile centre piece for the bow and stern  as you see to define the shapes of both, when it's all glued together it should be a pretty easy job to complete the carving.  I am targeting a final thickness for the yellow cedar of 1/4 inch, so that's what the sections overlap each other by for gluing. 

Just to make it more complicated for myself, I am going to have to make a hook knife to carve the inside.


Monday, 14 May 2018

The keel goes on.

Today I tried the keel back on the hull after removing the styrene I referred to in my "First Try" post.  I was delighted with the fit, after finish painting and varnish the joint will be hardly perceptible. 

But just on the keel side of the joint the surface flared a little from the base keel surface.  So the second picture shows the whitish scraping of epoxy filler that I added to take out the flare.  There's the same effect on the other side.
Once that is sanded I can put on one more coat of epoxy over the whole keel, wet and dry sand it to fair, and finish it with black paint.  On the hull just above the keel joint I plan to paint the first inch black and then fade the black into the transparent finish of the main hull. 

I,m thinking maybe I should make this into a build blog with flashbacks, so here's a couple of pictures from way back at the start in 2016.

The first shows the initial assembly of the moulds on the frame.  This was following practice by Nick Schade, who has an excellent kayak building site.
Instead of the mould being referenced to a building board outside the hull, they are assembled on a 3 inch square aluminium tube running down the centre of the hull.  The idea is that then when the hull is complete, the deck can be assembled on top of the same moulds, then taken off and the moulds and strongback removed.  The centre three mould sections were made to fold about the vertical centre, to get them out from the tumblehome, and the rest of the moulds slid along the strongback to the centre to pull the whole lot out.  Go enjoy an hour on Nick's site to get this clear.  It's great fun and the music is really good.
Also in this picture is the cedar keel plug, bread and butter assembled in place on the hull.  Its lowest layer was built into the hull planking, the lead line being just above that, and then the rest was carved into an airfoil shape, cut so the front formed the plug for casting the lead, and the back fibreglassed back onto the finished lead to make the keel as in the top photos. 
The final photo shows the cedar planking about 3/4 done.  The cedar planks were 9 mm by 3.5 mm, and their edges were moulded convex one side and concave the other as in standard cedar strip canoe practice.  Because that was the whole idea of this hull for me, that there would be almost no internal framing, just like a cedar strip kayak.  Right now the plan is to have just one single deck beam under the mast step, with a compression strut from the underside of that down to the keel.  I'm going to try to keep the rest of the hull completely clear, just mounts for the radio, servos, and battery.


Monday, 30 April 2018


But in a good cause, I am going to use the motor in a new model.  Probably a Fort Ship, if my current enthusiasm for that particular story continues.

I have used a cordless drill motor in a previous build, a springer for my grandson, The Bionicle Combat Tug.  He wanted a lot of power, and I had one knocking about so I put it in driving a 40 mm prop directly.  It certainly overpowers the Springer, I have had to pull back the throttle setting on the transmitter to stop the thing nose-diving.  I'm not planning on changing anything on that boat, my grandson loves the excess power, but it does seem to be a bit of a battery hog, it ran down the 4.5 amp-hour lead acid in it in just a bit over an hour.

Anyway, over the weekend I was vaguely musing in the car as my wife drove us up to Courtenay, thinking that I had been very pleased with a previous Springer, using a smaller motor with a 2:1 belt reduction to the prop, again a 40 mm.  It has a very similar top speed to the bigger motor, after all it's the same hull, but seems to be less fussy and to have much more battery life.  Thinking back to when I got the cordless drill motor, by dismantling a thrift shop bargain, I realized that I have had my own old cordless drill languishing in storage for more than a year since it's batteries finally died.  These drills have an epicyclic gearbox in line with the motor which I have previously just discarded, but maybe it was worthy of a closer look.

So, the first photo shows the strip down.  In fact there are three epicyclic trains in the old drill, two to provide two speeds, 0-600 rpm for screwdriving, and 0-2000 rpm for drilling etc.  Then a third epicyclic train provides the mechanics for the torque control and the hammer drill effect.  It's a lot of gears.

As I pulled it all down, I found that in fact it becomes quite simple for my purpose.  The first train, closest to the motor, is the first reduction that provides the higher speed drive (0-2000 rpm)  and that's a 3.3 :1 ratio which should be ideal.  So the second photo shows the motor and gear housing with the first reduction planet carrier .  Inside the housing you can see the sun gear mounted on the motor shaft, and the ring gear around it.  The ring gear is fixed to the housing so the planet carrier is the output.  The quality is remarkable, if you look closely you can see that the planet gears each have their own roller bearing.

Now if I can work out how to connect the prop shaft to the gear on the other side of the planet carrier, (shows in the third photo), and then cut back the length of the gear housing on the motor so that everything will hold in place, including grease, I'll have it made.

Nothing in the gear train will then be designed to take thrust, so I shall need to ensure that the prop thrust definitely bears on the ends of the prop shaft, but that's normal.


Friday, 27 April 2018

A first try.

This is my first attempt to post an entry to the vmss website blog.  So it's really just a test.  But just to add interest, I'm going to try to add a picture of the work that I'm doing today on my "A" class.  I have been trying to fair in the demountable keel to the hull by putting a piece of waxed .020 in. styrene in the joint, adding epoxy filler to both sides, and then sanding back both the filler and the styrene to get a fair joint.  The styrene is intended to peel clean off the epoxy to allow the joint to split again, and then both sides should meet very closely when the keel is remounted. That is 40 lbs of lead on the front of the keel.