I covered the Styrofoam bulkhead shapes with a layer of fiberglass roving using a light coat of spray glue to hold the fabric in place while I fully whetted it out with epoxy resin. I wanted to make the bulkheads light but strong, so I vacuum bagged the wet layups.

I use Elmers spray adhesive for a temporary bond when I know that I will be using a vacuum bag to keep the whetted fabric next to the form. This glue tends to dissolve when epoxy is introduced, so it does not seem to clog up the weave and prevent epoxy from fully whetting out the fabric and bonding to the form. As you can see from the photos, Elmers glue allows me to wrap the form up nicely – kind of like wrapping a birthday present. I use 3M high strength 90 when I’m not using a vacuum bag, as it does not seem to dissolve with the epoxy resin and the whetted fabric won’t lift up or peel off the surface. the problem with the 3m 90, is that since it does not dissolve, the epoxy doesn’t fully soak into all of the weaves in the fabric – it seems to wet out about 75% of the fabric though, so probably more composite material is required to offset this. I’m not sure – it would be interesting to do some testing some day and find out exactly how much various spray glues impact on the strength/weight ratio of composite materials and epoxy resin.

They came out really nice – light and strong and tightly wrapped in glass. I bonded them into the kayak hull using epoxy/micro and radiused the inside corners nicely. Now I am going to place a strip of fiberglass roving along the joins to further solidify the bulkheads to the kayak.

I filled the bow and stern compartments with Polyurethane expanding foam. This foam is buoyant enough to support 60 lbs of weight per cubic foot. I estimated that 2 square feet of this foam should be good enough for Within-24, since Within-24 won’t feature the top deck. I’ll add more foam in the bow and stern compartments of the top deck, plus the deck has quite a bit of Styrofoam as it’s core, and will probably float all on it’s own.

The reason for these two solid floatation compartments is if the boat were to completely flood, it would still stay afloat due to these two sealed off, solid buoyancy areas. For Within-24, since there aren’t any additional compartments filled with air, I’m thinking of strapping in some air filled water bottles under the soft deck just in case.

Drive leg bay

I started the fiberglassing of the drive leg bay. There are two
purposes for adding fiberglass to it, one is structural – to make the
drive leg bay a structural part of the kayak hull, and the other
reason is to water proof it. The first layer is water proofing and
runs around the kayak hull bottom, up and over the DL bay walls and
then a few inches onto the floor.

The bay is a very complex shape, and the glass fabric running along
the inside of the narrow part of the bay frame has to be very thin
because the drive leg struts fit in there pretty tight. I used 3M
super 90 spray glue to hold the fiber glass fabric down to the form,
then whetted it out with epoxy resin. The resin does not seem to
dissolve this glue, so it holds it’s position VERY nicely – almost
like it was vacuum bagged. The only issue that I have, is that I’m not
positive that the epoxy is fully saturating all of the threads in the
fabric due to this spray glue. However, a tight fitting glass covering
is also a very important aspect of sealing and structure.

I plan to add a least one more layer, then some thicker roving to the
edges for structure.

Adding the glass have me an opportunity to finally insert the drive
leg, prop the seat up and get in for a quick spin. Everything feels
just great!

Mechanical efficiency test

I was also able to test the mechanical efficiency of my drive. The
last time I did it, I determined that there was a 8 watt loss due to
the chain / cog / gear box. I repeated the test, this time with the
completed drive leg and the loss was 7 watts. So, it does not appear
that the chain clanging in the stainless tubes is responsible for any
measurable losses.

I need to point out that this 7 watt loss is 7 watts from free
spinning of the crank and chain ring without any chain. 7 watts of
power is required to turn the chain, turn the small cog on the gear
box, and to turn the gear box. All of this work needs to be done
regardless of what kind of method you have to get the power down to
the prop, so it’s not really a ‘loss’ so to speak. It’s just a cost of
getting the power to the prop – watts that won’t directly be producing
any forward thrust.

For comparison purposes, Rick has a drive now that takes 5 watts, and
has made a gear box that took only 3 watts. But that gear box was too
small for this design, and was filled with a high viscosity
lubrication – again, not applicable to my drive. 6 or 7 watts could be
normal, and I think with a double right angle gear drive with a shaft,
it could be as high as 10 watts.

Bulkheads

I cut out 3 Styrofoam bulkheads and 2 wood bulkheads. The two small
1/2 plywood sections fit on the sides of the drive leg bay and run out
to the kayak walls. These will add structure to the drive leg. The 3
Styrofoam bulkheads are for the small solid buoyancy compartment in
the bow, the bow compartment (which also acts as further structure for
the drive leg), and the main cabin bulkhead behind my seat.

I measured the curves using my curve guide, then traced the shapes
onto cardboard and messed with the cardboard shapes until they fit
nicely into the kayak hull. Then I traced the shapes onto some 1/2″
thick Styrofoam and carved and sanded them.

Next, I will cover them with fiberglass and then glass them into position.

Rudder

Here are some shots of the rudder in the rudder steering shell tube. I still need to sand down the rudder top more so that it fits flush to the bottom of the hull

Actually, that should read “Changes TO Within”

The design of Within – my prototype human powered ocean boat has been changed a bit with an eye toward safety. When I traced the outline of my retractable canopy top onto the deck, I realized just how freaking HUGE that thing is. I tried to imagine what kind of hinge would be beefy enough to hold that top on and I just couldn’t fathom anything that could withstand a rogue wave smashing into the side of it. I could just see that top ripping right off Within.

It’s happened before, and I can think of two fatalities. First of all, Adrew McAuley’s dome cover was missing when they found his empty kayak 75 km off the the New Zealand coast. Secondly, Nenad Blic’s ocean rowing boat was found capsized and flooded off the coast of Ireland and the hatch was missing.

I also realized that getting into and out of Within while at sea would be nearly impossible with the canopy top the way I had it. We want to keep the center of gravity as low as possible in Within because low C of G requires less ballast to keep it stable, which translates to more speed.

I realized I needed a better hatch, and I needed to keep the top of Within permanently ON the boat. So what I did, was decided to go with a standard Lewmar ocean hatch on the side of Within slightly above the water line. This would allow me to climb into the boat from the water without raising my center of gravity.

I re-designed the seat to slide forward and recline down to horizontal to allow me to flip around onto my stomach, open the rear hatch and crawl into the sleeping cabin. With the seat lying flat on the floor, I can also open the side hatch and slide into the water – and back into the boat again. All of this, I can do while keeping my center of gravity low, and keeping Within stable.

Of course, I plan on testing all of this before I go and cut holes into Within for the ocean hatch. I’ll make a cardboard cutout hole and practice getting in and out while in the pool.

This change is not without it’s problems. Mainly, I need to consider how I will get enough ventilation in the tropical Atlantic ocean without being able to remove the top. I will add a small window at the top and that be opened partially, as well as be able to open the side hatch a bit – these windows should automatically close if the boat were to ever capsize. I will also have some directional vents through the deck. That probably won’t provide enough fresh, cool air, so I may need to look at adding a fan to direct outside air in and through the cockpit. The space on the top of the deck is limited, so I can’t rely on square miles of solar panels to power every convenience I can imagine. I wonder how much power air conditioning consumes…. Any such thing as a miniature, lightweight, super efficient air conditioner?

The other change to plans is the addition of ‘phase 1’ to the prototype boat. I’m calling it “Within-24”. It’s Within without the full deck, and it will be used to go after the 24 hour human powered boat distance record this summer. The topless boat will be lighter, a bit faster, and easier to haul around – much better for a record attempt.

Within-24 is a good intermediate stage for the development of Within. I can fully test out the weight, balance and stability of Within, the rudder and steering, the prop, pedals, seat, etc, etc. Once all of this has been firmly set to the way that works, I can go ahead and bond the top deck to it and finish off the prototype boat. Then I’ll get out into the ocean with it and get into phase two testing.

These sexy new renderings of Within were created by the Benmeister:

Ben shot this picture of me and Within and automatically tiled it using this slick software utility called ArcSoft Panorama maker

The first step in getting the drive leg bay frame secured to the kayak floor, was to prepare the floor. Since it isn’t completely level, I had to build up one side to meet the drive leg frame such that the drive leg is level and straight. I built up the left hand side with many layers of fiberglass, then smeared epoxy/micro all over the floor and pressed the drive leg bay frame into it. Then I worked the micro into the corners and smoothed a nice radius around the frame.

After the epoxy/micro hardened, I flipped the kayak around and cut out the hole. that was NOT easy to cut!! It’s pretty thick down there and I burned out my SECOND dremel!

I made a flange for the drive leg bay with 1/16″ stainless plate strips that were welded together. This flange is supposed to fit on the bottom of the kayak and screwed into the drive leg bay frame sandwiching the kayak hull between the bay frame and the steel flange.

The flange was a real pain to make – I had to weld a bunch of 1″ strips of steel together, grind it smooth, then drill and countersink all the screw holes.

After I started to screw the flange onto the hull bottom, I didn’t like what I was seeing. Rick Willoughby says that in water, drag is about 800% greater than in air. So – imagine a 1/8″ screw bump magnified to a full inch! The flange wasn’t sitting flat enough, and I was having problems with some of the screws stripping, etc. I didn’t like what was happening, so I removed the flange.

After thinking about it, I don’t see why I couldn’t make this strong enough wrapping fiberglass around the hull bottom and up the inside of the bay wall, and a couple of bulkheads connected to the drive leg frame in both the front and rear. We’ll see what Rick thinks about that.

I also mounted the rudder shell tube – the rudder steer tube slides into this. I welded a flange onto the bottom of the shell, drilled a small hole in the floor, and micro’ed the flange down to the floor. I also welded a tab about 8″ above the bottom of the tube, and screwed it onto a plywood bulkhead. Then I micro’ed the bulkhead into the hull. Then, I wrapped the whole assembly with my thick fiberglass roving. I still need to screw the flange to the hull bottom.

Another training ride – only 3 weeks to go!

I was out today for the second bike ride of the season. This kind of sucks because I only have 3.5 weeks until Ironman Arizona All of my bike training so far has been inside on the mag trainer. You don’t realize how much harder you work outside until you get out for your first ride. Now that the weather is so-so, I’m going to try to get out for as many rides as I can over the next 2 weeks.

Other than that, I think I am ready. My running has never been better – higher speeds at a slightly lower heart rate. The reason is because of a trick I discovered about running more efficiently and I’m not telling. Yet. I need some more data, more time and one good race (Arizona) before I can really speak about this. I will tell you this though – at a heart rate of 135-140 bpm, my old pace was 8 min/mile. Now it’s 7:30 min/mile at the same HR. My PR marathon (marathon-only, not an Ironman marathon) time of 3:17 could theoretically drop as low as 3 hours. It’s been a dream of mine to run a sub 3 marathon, and I think I just may be able to do it someday.

I would be thrilled to do a 3 1/2 hour marathon at IM AZ. We’ll just have to see what the day brings. You can’t be guaranteed anything on Ironman day. I know that all too well. Anything from forest fires, to freak wind storms, to sweltering heat waves can happen.

My bike seems to be pretty good also – hard to say. The reason is that my watts/heart rate is higher than it’s ever been, meaning that my economy is improving, but like I said, my first outside ride last week was an eye opener! I’m not sure what kind of muscular endurance I have in my legs to push 220 watts for 5 hours straight. I certainly wasn’t there last week, nor was I any where near where I need to be today.

My swimming is very average. Well, poor in comparison to where I really should be, average compared to old ladies and toddlers, but pretty good relative to previous levels of fitness. I did a 1500 meter time trial with the wet suit on the other day and hit a personal best time of 25 minutes, so that’s not bad. Again, my swim volume has been fairly low – averaging only 2 to 3 hours per week, so I don’t know how that’s going to effect me in Phoenix.

Comparing my training schedule to last year, I was surprised to see that I have put in less training hours since Jan 1, as last year at this time! I think this year my training has been of higher quality. I’ve dropped out all of the low and slow stuff. Most of my rides are steady state without any coasting and no recovery rides (inside mag trainer work), my runs have all been FAST – minimum 8 min/mile pace, and well, swimming is just what it is…

2006 Swim=34.15 hours, Bike=136.4 hours, Run=66.95 hours

2007 Swim=31.38 hours, Bike=122.3 hours, Run=50.5 hours

My race day goals? Well, I’m not stressing the swim – I can do a PR in 1:10 or an average IM swim of 1:15 which is only 5 minutes difference. I would like to repeat my 5 hour bike leg from last year, and like I said, I would be thrilled if I could do a 3.5 hour marathon. If the plan materializes on April 15th, it should get me pretty close to 10 hours and possibly 1st or 2nd place in my division. I placed 4th last year in Arizona. But like I said before, I know anything can happen on race day, so if this goal is out the window, then my second goal would be to qualify for Ironman World Championships in Kona again – typically, this requires a top 8 finish in my 45 to 49 age group. If that fails to materialize, then I would like to break 11 hours, and if that doesn’t happen, my last goal would be to simply finish the race.

When the drive leg pivots into place in the frame, it is sandwiched between two narrow rails in the frame, but to firmly secure it while being used, I needed something more. I welded a stainless nut to the drive leg bay frame and with a threaded knob from an old exercise machine, I can screw the drive leg down tight the frame.

I filled the tubes on the drive leg bay frame with epoxy, then cut out plywood panels to fit between the stainless steel tubes. Then I sealed them all in place with an epoxy/micro mix. I will cover the whole frame with fiberglass once it is fixed to the kayak floor.

I messed up with the positioning of the drive leg bay. I had centered the frame in the kayak with the narrow drive leg slot in the middle of the hull instead of the middle of the bottom bracket. I realized this today thanks to a comment from Mikael – thanks! This means that I can now move the DL back to where it was originally planned, and my frame cuts still work. cool.

While waiting for the epoxy to cure on the wood panels, I started in on the recumbent seat bracket. The seat is a fiberglass recumbent seat from PowerOn Cycling
Actually, I scarfed it from my Rocket lean steer velomobile (my bad) – I’ll have to order a new seat to replace it because I really do want to get the Rocket on the road for this summer.

The seat will slide back and forward on two rails that will be bolted to the drive leg bay frame. The rails will also be bonded to the kayak hull floor. I hinged the seat directly below the seat bottom so that I can lay the seat flat on the floor for entry, exit and access to the rear compartment. I’m not 100% sure about how the seat back will be supported yet. My idea was to build the rear compartment bulkhead wall sloped and put a skateboard wheel on the seat back. This would allow me to release the seat rail lock, slide the seat all the way forward and have the seat back roll down the rear bulkhead wall until it is flat on the floor. All the time, my center of gravity remains low – no need to sit up and twist around. I’ll just slide forward, roll around, knee and open the rear hatch, then crawl in. Well, that’s the plan anyhow – I’ll set up a mock-up to see how that works before building the seat back support, bulkhead and rear hatch. I will also need some way of securing the seat back firmly to the rear bulkhead wall when in use.

Just to see how the deck and hull matched up, Ben and I placed Within’s top deck onto the kayak hull. They match-up fairly close. Some bending and spreading will be required. Cool – we’re getting there.

Well, that was fairly painless.

I carefully measured the curve of the hull using my flexible drafting curve and traced the curve onto the steel frame. Then I cut out the long tube completely, and carved out the curve on the end tubes using my Dremel cutting wheel.

The cuts worked out perfectly!

I filled the open sections of the cut tubes with a new strip of 1/16″ steel and welded them closed. Then I re-inserted the long cut-out section to match the angle of the hull. It fit perfectly. I welded it in place and now the drive leg bay fits nice and flat against the curved hull.

I only had to move the whole drive leg back about 8″ – not so bad.

Now I am filling the hollow tubes with epoxy, then I will epoxy plywood panels into the frame to enclose the frame. I’ll do this before I mount the frame on the hull, as it is much easier to do with the bay frame out of the hull. Here are the next steps:

1. Using the frame as a template, I am going to cut out a 1/16″ stainless steel flange. This flange will screw to the bay frame from BELOW the kayak hull – sandwiching the fiberglass kayak in between the flange and the bay frame. The flange will have the exact same inside dimension of the frame, but will extend about 1 inch outside the frame on all sides. I will also pre-drill countersunk screw holes into the flange.

2. Position the bay frame down onto the hull with a thin layer of epoxy/micro to level out all the small bumps, etc on the fiberglass floor. I’ll let this cure so that the drive leg is bonded to the kayak floor.

3. Flip the boat over and position the flange on the bottom of the kayak hull onto a bed of epoxy (sand the gel coat on the bottom of the kayak first). Using the flange holes as a template, drill through the flange, the kayak hull and into the drive leg bay frame.

4. Screw the flange into the hull & bay frame. (fill the holes with epoxy as you insert the screws

5. Now, cut out the drive leg hole in the kayak floor using the bay frame and flange as a template. This is the structural connection between the frame and the kayak – well most of the structure. The front and rear of the drive leg bay will also be bonded to a bulkhead that will connect the side walls of the kayak to the drive leg frame. This should be extremely strong – probably stronger than the kayak itself.

6. To water proof the bay, I will wrap a layer of fiberglass over the flange and up the insides of the drive leg bay frame walls, over the top, down the other side and across the floor of the kayak. Then I’ll radius all the corners using some thick epoxy/micro mix.

I should weld the seat rails to the front of the bay frame before I do all of this, but I would rather have that drive leg bay fixed and in place before messing with the seat. So instead, I think I will weld some tabs to the ends of the seat rails and bolt them to the bay frame. I should weld some nuts to the bay frame before filling with epoxy.

dumb, dumb, dumb, dumb….

For those of you who haven’t been following this along in a super technical way, the “drive leg bay” is a water tight frame that is built into the kayak hull with a hole in the bottom so that I can insert and pull-out the propeller/pedal unit – called the “drive leg”. The reason I don’t simply build the drive leg into the kayak hull as a permanent part of the boat is because I need to be able to pull the drive leg out to service it (lube the chain, replace the chain, etc), and also I need to be able to raise it during testing in case I need to beach (and for transportation). Don’t ask me how I plan on raising the rudder yet… It’s pretty dam tough, and it’s way in the back, so I will be able to remove it from the outside of the boat once close to shore.

And while we are in ‘refresh mode’, I want to go over some of the reasons I decided to go with a chain and gear box for the drive leg rather than one of many other approaches to a drive, like a shaft, or twisted chain.

When I started to design the drive unit, I set a few design constraints:

1. I wanted to use as many standard bike parts as I could. The reason is that I simply trust these bike parts that I have been using for years and years. I have thousands of miles on some of my chains and they are still in VERY good shape. They take water, dirt, mud and abuse on my bike they would never see enclosed in a stainless steel housing at sea. I can buy lightweight bike chains, stainless steel bike chains, carbon fiber bike cranks, a few dozen different types of pedals, various sizes of chain rings, gears, etc, etc. Replacement parts are easy to find, and fairly easy to replace with standard bike tools. I have plenty of experience working with bike parts.

2. Re-build. Although the plan is to bring a couple of spare drive legs, I also wanted to be able to completely overhaul one of these on the support boat if I absolutely needed to. I can pull every single component out of the drive leg and replace it with a brand new one in less than 30 minutes.

3. SRM watts meter. I wanted to build a drive leg that would work with my SRM power meter. In training and testing, it is VERY important to me to be able to monitor and measure the level of power I am putting into the drive, and resulting speed I am getting out of the human powered boat Within. This was a vital aspect of the human powered vehicle 24 hour record I set in Critical Power HPV. The EarthRace guys
constantly monitor how much bio fuel their record boat is consuming and are constantly calculating the on-going efficiency of the engine and props and systems. My ‘engine’ is me, and I need to do the same. I constantly monitor and record my heart rate, cadence, power output, hydration, speed, etc. The SRM makes all of this possible, and you can only use it on a Shimano bottom bracket.

OK – on onto my dumbness…. When I first designed the drive leg bay, it was fairly short – only long enough to slide the drive leg forward, then pull it up and out the top. I may decide to NOT cut out that huge canopy top on Within, so pulling the drive leg straight up and out is not an option. So, I redesigned the drive leg bay to allow the drive leg to be rotated out of the water.

This was really slick and worked really great. I welded on a hinge and was very happy and proud of my wonderful creation.

I failed to place the new longer bay into the hull to see if it would fit!!! Duh! Well, it doesn’t fit. It’s too long. The bottom of the hull curves up and the drive leg bay won’t sit flat on the floor. One of the reasons I built the bay out of stainless tubing is that I didn’t want to compromise the structural integrity of the hull when I cut a giant hole in the bottom of it to stick the prop strut through. I wanted it to be super strong. Once a flange is fitted to the hull bottom, all of the stresses on the boat will be routed around that steel frame.

So, I either need to move my drive leg way back (toward the stern), or cut it up to allow for the hull curve. Moving it back too far is not an option because it starts to really mess with the weight and balance estimates, my head will be too far from the front window, and I start to greatly reduce my sleeping cabin in the rear.

It looks like I’m going to need to cut the bottom tubes of that frame out and re-fabricate to allow for that hull taper. Not a huge deal, but will definitely require some delicate measuring, cutting and welding.

Well, I think I will blow off my training for today (did a real hard 5 hours yesterday and have a 6 hour day planned for tomorrow), and start the drive leg bay operation. I’ll go prep the operating room now. Stand by and say a prayer.

Since weight down low in this human powered pedal boat is a good thing, I figured that I might be better off building the drive leg bay out of stainless steel square tubing. That way I can be assured that it will be strong enough to efficiently transfer power from my seat, to the cranks, through the drive leg, and drive leg well, then down to the prop. The seat will be bolted to two stainless steel rails which will be welded to the drive leg bay frame.

I originally had the drive leg pull straight UP and out of the bay, and in order to do so, I required the canopy top on Within to be open. We are now talking about NOT cutting out the canopy top and leaving it as a permanent part of the deck. I would add a small standard ocean sail boat hatch on the top for fresh air, and a larger standard hatch on the side to enter and exit.

Reason? Well, I’ll get into this a bit more when I have a plan to show, but basically I am really nervous about building an adequately strong latch hinge for that huge canopy top. I am familiar with a few cases of the ocean ripping off large overhead custom hatches. In my imagination, I can see a monster wave ripping that over-sized canopy top right off of Within. With the smaller commercial hatches closed, Within will be more like a submarine than a boat – much like the EarthRace boat – Speaking of which – have you checked that baby out yet? That thing is fully sick man! The EarthRace crew are attempting to break the round-the-world power boat record with their wave piercing bio diesel speed boat.

So, if I decide not to cut out that canopy top, I am going to have to come up with some other way to remove the drive leg for servicing, or for beaching (during testing and training). What I came up with was pretty neat. I extended the length of the drive leg bay and added a hinge to the drive leg. The leg will now simply rotate out of the water like the gif animation below:

I designed the new bay with a computer model to get the basic dimensions and clearances right.

Then I constructed a cardboard mock-up of the bay and tested the drive leg in it. I even made a cardboard propeller based on the prop dimensions Rick W has calculated for me.

Then I cut a few dozen sections of 3/4″ square stainless steel tubing, assembled it all and spent the better part of a day welding it all together.

Wow – this thing is majorly solid! I am going to weld a nut into the drive leg to bolt it firmly to the well frame when peddling, but it fits so nicely into the slot right now, that I don’t think it will require any additional fasteners. Once that hinge is on, it will probably only require a lock to hold the other end down to the frame.

To bond the bay frame to the kayak hull, I will first screw through the kayak hull into the stainless frame (counter sink the screw holes and fill with micro), then wrap fiberglass around the bottom tube and around to the underside of the deck. I’ll insert Styrofoam tiles into each open side of the frame, then glass around the whole thing to make it water tight. I DON’T want to weld plugs onto all of the tube ends on the frame – I wonder if filling them all with micro/epoxy, then giving the whole steel frame a few good coats of epoxy will make it all water tight?

To better secure the drive leg bay to the kayak hull, it will be bonded to a bulkhead at the bow end of the bay, and a partial (short) bulkhead at the stern end of the drive leg bay. The seat back will be mounted to the rear bulkhead.

This was the view outside my shop window this morning. I was outside on Tuesday for a 6 hour bike ride – the first outdoor ride of the season. By the time we rolled in, it started snowing. No outside rides this week. I need to get outside to get some rides in! Ironman Arizona is in 5 weeks.

First, there is a new riveting episode of the Pedal The Ocean podcast. You’ll be on the edge of your seat as you listen to me drone on about SRM meters, watts, aerodynamics and why I think it’s important to our modern society to become more active.

http://www.racerecon.com/webcast/0006/

or visit the podcast page at the BLOG

Prop Screw up

During the design phase, I misinterpreted the proposed diameter of the prop and only allowed enough room below Within’s hull for a 12″ dia prop. Ricks design calls for a 17.7″ diameter prop! Oops.

I had added a couple of ‘safety’ inches to the length of the drive leg, but was it enough?

In my computer model, I dropped the drive leg down so that the 17.7″ dia prop just cleared the hull bottom. Then I added about 1/2″ for the hull skin thickness and took a measurement from the hull floor to the center of the crank. This, I figured would be the highest I could have the crank without having to rebuild the drive leg. The question now, was the 10.75 inches of clearance be enough to circle my feet without my heels rubbing.

I set up a mock drive on the floor using my fiberglass recumbent seat and the drive leg propped so that the center of the bottom bracket was the crucial 10.75″ distance from the floor. Then I clipped in and peddled normally. It was good. Whew! My heels are the tiniest fraction of in inch from the floor, but it works. If I need slightly more clearance, I can move my shoe up on the cleat or go with slightly smaller cranks.

This is good because it keeps my center of gravity as low as physically possible. My seat is right on the floor of the hull and the angle of the seat back is quite reclined. Even with my feet circling around the raised cranks, I would think that my over all center of gravity would be not that much higher than standard sea kayak sitting position where your back is straight up and down.

More Rudder Madness:

more progress on that rudder – I welded a stainless rudder tube with some offshoot ‘branches’ to insert into the hollow rudder shell. These stainless branches will provide something for the epoxy filling to ‘grab’ onto and will make it pretty strong and stiff when torqued hard.

I also filled the rudder steer tube up with epoxy to further strengthen it and to seal it from the potential of water running into it and down into the rudder shell.

I inserted the rudder steer tube and poured epoxy resin into the rudder shell.

Next on the agenda is to build the drive leg bay, seat and partial bulk heads (for the kayak hull only – I’ll extend them up and into the deck when I get to bonding the deck onto the hull).