The View Up Here

Random scribblings about kites, photography, machining, and anything else

Archive for March, 2012

On Boat Names and Faking Sails

Posted by Tom Benedict on 31/03/2012

The wind here is still insanely high. Too high to fly a kite. Certainly too high to raise a sail on a boat that’s still tied to a trailer. At some point I need to start checking out line lengths on my mainsheet, and I need to thread up the jib sheet to a good workable length. This is easiest to do with sails up. But that’s simply out of the question. My plan, at the moment, is to fake the sails.

Faking a mainsail is easy. Most main halyards are long enough for you to clip them to the outer end of the boom and use them as a topping lift. (A topping lift is a line that runs from the masthead to the outer end of the boom on a large sailboat. When the mainsail is down, it holds the boom up off the deck. When the mainsail is up, you can use the topping lift to set how much curve you want in leech of the sail (its trailing edge).) If the main halyard isn’t long enough, it’s a simple matter to tie a bit of line to the end and use that as an extension. In the end you get a boom set at about the same height as if the sail was actually there.

Faking a foresail is only a little more involved: Lay the sail on the ground and use some scrap line to duplicate the outer edges of the sail. Tie loops in the corners so it can be rigged in place of the foresail. Voila: faked out foresail with no real sail area. It’s a lot floppier than a real sail, but with a little creativity you can still use it.

Once the boat is rigged with fake sails, you can attach the sheets. This lets you work out how long the sheets should be and will let you see how they’ll lie on deck when tacking or jibing. If a sheet is too short, you won’t get the full range of motion you might want. Too long and it leaves a tangle of line on deck that’s prone to fouling or being swept overboard. The trick is to strike a good balance.

It’s also a good way to introduce new crew to some of the concepts of sailing before they get wet and cold. Since this will be the first time any of my kids have been out on a sailboat, this is one of the things I’m planning to do with them. With the fake sails up, we can show them how to come up on the wind before a tack, how to sheet in the traveler during a jibe to reduce the forces on the boat, etc. And with a little practice we won’t have them cracking each other’s heads as they dive across deck during a tack.

Speaking of the kids, the boat’s name is still up in the air and they’re still coming up with more good ones every day. My wife, on the other hand, is starting to shoot some of them down. Two of my favorites, Millennium Falcon, and Serenity, were among the first to be nixed. Here’s her logic:

One of the defining characteristics of both the Millennium Falcon and Serenity is that they’re in a constant state of disrepair. This was used to comic effect in both Star Wars and Firefly. It played a major plot role in both as well (the broken-down Millennium Falcon in The Empire Strikes Back, and Serenity in Out of Gas). Naming a boat after one of these is kind of like tattooing wings on your back if you’re a sky diver. It’s just asking for trouble, in her opinion.

I’m not sure I agree 100% since both the Millennium Falcon and Serenity had other qualities that endeared them to viewers and crew alike. They’re desirable despite their flaws. In some ways it’s because of them.

But she does have a point. “… despite their flaws” is the operative phrase there. I think we can make this boat desirable by the time we’re done. And yes, it will have flaws. But one of the things I don’t want to do is to wind up with a boat that is in constant need of real hard-core repair. I want to hook up the trailer, take it to the water, rig it, and sail it. I know that every boat on the planet is in constant state of requiring maintenance. But I don’t want to worry about blowing a compression coil or losing my hyperdrive each time I set foot on it. Maybe those names really do summon trouble.

There’s another class of names we may or may not go with, depending on how some of the repairs go over the next few weeks. “Ugly Cat” “Bad Kitty” and “Calico Cat” fall into these. I’m driving into Kona today to pick up supplies for repairing the gel coat on the lower hulls and the rudder blades. The blades are no problem. They’re white. But the hulls are this odd faded off-white that was clearly popular in the late 60’s and early 70’s when the boat was made. Color matching it now might prove more trouble than it’s worth.

The hulls have impact dings and scratch marks all over them. It’s going to require many many repair sessions before I trust it in the water. Depending on how my color matching goes, “calico” may be a kind description of its new color scheme. But if I find a good match and can replicate it from session to session, the hulls may wind up with a mirror-smooth finish that looks factory original. (Hey, I can dream!) Then that whole bunch of names won’t apply, either.

Which makes our list pretty short. My son threw in the name “The Bunny”. He likes rabbits. Who knows? It may stick.

– Tom

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A Lesson in Availability of Stuff

Posted by Tom Benedict on 30/03/2012

I’m still working on the boat. A whole bunch of parts are on order, but nothing has come in yet. In the meanwhile I’m learning how to compound, polish, wax, and buff fiberglass (well… gelcoat, actually.) This weekend I’ll start plugging holes with West Systems epoxy, and repairing all the dings in the gel coat below the deck seam. Fun weekend. I’ll be a zombie by Monday.

Getting the parts ordered has been something of an ordeal. The reason for this is that we’re isolated out here. It’s hard for people to really understand this until they move out here. (“Here” being the Island of Hawaii.) I’m used to running into this with stuff we use at work. Need a specialized engineering material? Hop on a web browser. Need metric fasteners? Web browser. Tooling? Web browser. Precision measurement tools? Browser. The local stores do carry some stuff, like hand drills. But try to find a 115 piece drill assortment with fractional, letter, and wire size drills? Not on your life.

But Hawaii is largely a maritime culture. People here surf. They wind surf. They fish. They use boats. They free dive. They live on the water. I thought it would be different with a boat. Oh boy, was I ever wrong.

Prior to this my sailing experience was largely confined to the lakes around Austin, Texas. This is where my friends and I owned a Prindle 16 catamaran. Great little boat. An utter blast to sail! And with the Sailboat Shop right there in town, we were able to get just about anything we needed same-day. Need line for a mainsheet? No problem. Need a new halyard? No problem. Rudder castings? Gudgeons? Hot sticks? No problem. If they didn’t have it, they’d get it. No problem.

So when I checked out the marine stores in Kona, I had high hopes. They didn’t stay high for long. Now don’t get me wrong. They had a lot of what I was looking for. West Systems epoxy? No problem. Gel coat? No problem. Steel pins and rings? No problem. But shackles? Errr… Cheek blocks? Ummm… Harken mainsheet hardware? Well… No.

I can understand, in a way. The boating culture here is largely based around fishing. People don’t tend to fish from sailboats. They fish from power boats. Real fishing boats. Need a diesel part? No problem. But a sail headboard? Not gonna happen.

Still, I was surprised by how far this difficulty extended. Here are two examples that bit me harder than I cared for, and certainly harder than I expected:

I drive a 1992 Jeep Wrangler. It’s an honest to goodness 4WD vehicle, and it gives me access to spots on this island I couldn’t otherwise reach. Should be a natural tow vehicle, right? Right. So getting a hitch should be a snap. Wrong! I found one shop on the island who would install a hitch for me. One. They were willing to do it for the low low price of $450. In the end I picked up a hitch from Complete with light wiring kit and over a hundred dollars in shipping, it still came out under $250. See something wrong here?

The traveler car on this boat is shot. It still rolls, and the bail for the main sheet blocks is in good shape. But there are two threaded holes for the 3:1 traveler sheeting system that were utterly wallowed out. It looks like the traveler car is made of cast aluminum, so this didn’t really surprise me. It’s a common problem on heavily side-loaded screws in aluminum, and the fix is really simple: Drill out the holes and install Helicoil inserts. These are stainless steel threaded inserts that screw into a newly threaded hole. Since this meant I’d replace aluminum threads with stainless ones, it should result in a more durable part overall. This is why we use them on our instruments at work. Many of our instruments are made out of aluminum. If you expect a screw to go in and out more than about five times, you use Helicoil inserts from the get-go. They work.

I checked at the local hardware store. No dice. The local auto parts store did carry them, but only for 3/8″ bolt holes or larger. The guy at the counter gave me a couple of other spots to check, but no one had the one I was after (#8-32 – a common enough size). When I got back from running around, I checked Amazon. Hey, perfect! One of their partner vendors sells them for about $20. But no free shipping. What’s shipping to Hawaii? $25?! $25 shipping for a $20 part. You gotta be kidding me.

I finally found a kit on Ebay for $25 with free shipping to Hawaii. Buy it now, baby.

But I have to ask myself how hard it would be to find this stuff in Austin. My guess is you could get it at the Sailboat Shop. If not, I’d be willing to bet he could tell you where to go to get it without having to drive all over town. And even if you did have to order it, chances are it wouldn’t cost more than the kit just to send it to your door.

Friends at work are pretty excited about the boat. I’m eager to take them out on rides, so the feeling is mutual. One question people keep asking is, “Hey, how long ’till the boat is done?” Some days I don’t even know what to tell them. I think I’m at a point now where with the exception of one last order to Sailrite, I think I can get everything else locally. But then again, that’s what I thought about the Helicoil kit. Time will tell.

– Tom

Posted in Engineering, Sailing | Leave a Comment »

Progress on the Duckling

Posted by Tom Benedict on 27/03/2012

It’s a little hard to write about the work that we’ve done on the boat. It’s not that no progress is being made. It’s that we just never stop making changes. By the time I finish a draft for this post and set it aside to edit the next morning, the state of things has changed enough that I need a complete re-write! So this will be a rough and ready post, at best. But I wanted to put down something.

And no, “Ugly Duckling” will not be the name of this boat. Each member of the family gets to write names they think are cool on the white board at home, and once the boat is ready for the water we’ll vote and pick the best name. But for now we have to call it something!

When we received the boat, it had been sitting out in the sun and weather for roughly ten years. Since coming to our house it has continued to sit outside in the weather, but not the sun. It’s been cold and rainy. So forgive me if the color cast on some of these photos seem off. They are.

After a brief scrub and a bunch of chattering teeth, the hull started to look a little less moldy and a lot more like a boat:

Pacific Catamaran 001

In addition to the hull and trailer, the boat came with a mast, one foresail, two mains, two jibs, a complete tiller assembly, and a five gallon bucket full of stuff. Ok, it came with other stuff, too: PFDs, dagger boards, and what turned out to be two complete sets of standing rigging. But ready to sail it was not. Not all of the hardware in the bucket was usable, and not all of it made sense. Most of the pins for the standing rigging were missing, and much of the jib sheet hardware is damaged, dead, or just plain gone. Half of the blocks for the mainsheet were left out in the sun and were destroyed. And the upper deck is a nightmare of alligator cracking. . But considering this boat is likely to be over forty years old, that ain’t bad!

As a quick aside, earlier today my wife and I were flipping through Phil Berman’s Catamaran Sailing and ran across a picture of three Pacific Cats sailing in a group. Only one of those cats had a sail number smaller than ours. And that book was published in 1982!

Pacific Catamaran 002

So where are things now? Moving along, actually.Earlier this weekend we stepped the mast and took a look at what it would take to get this boat out on the water.

Stepped Mast

Here’s the list:


The mast is intact and remarkably straight. The diamond wires were not tensioned symmetrically, so I spent some time adjusting them. Unlike every other mast I’ve seen with diamond wires, tension is set by adjusting the width of the spreader bar rather than by turning turnbuckles near the base of the mast. This was a little weird to me, but it worked.

Looking Up Mast

The mast on the Pacific Catamaran 19 is odd in other ways, too. There’s an integral winch in the mast for the main halyard. It has a ratchet lock on one side and sockets for a winch handle on either side. The winch was frozen when we first tried it out, but some dry lube and a little exercise of the mechanism freed it up enough to work smoothly. The bushings are clearly shot, and will have to be replaced. But right now I can’t figure out how to disassemble it. It looks like there used to be a set screw in the side of the winch drum that let you remove it from the spindle. But it’s so nasty in there right now, I can’t figure out how to remove it. We’ll have to re-visit this down the road. For now, it works.

Main Winch

Both booms appear to be in good shape as well, though all three show signs of saltwater corrosion. I cleaned the shorter of the two booms, and will do the same to the other boom and the mast as time allows.

The Pacific Catamaran sail threads into a track on the boom, so there’s no downhaul on the mainsail and no outhaul car on the end of the boom. Instead, luff tension is adjusted using the main halyard, and outhaul is handled by a line threaded through the clew of the sail. Sorry, no pictures of this yet. (Did I mention that it’s been blowing hard in addition to the cold and the rain?)

Rudder / Tiller Assembly

The rudders are in remarkably good shape, considering their age. There’s some chipping of the gel coat, and one rudder has had one of its tips ground off. I’d like to seal this up before putting it in the water, simply so the foam core of the rudder does not degrade from saltwater exposure. But eventually I’d like to rebuild the tip, using the other rudder as a pattern. For now, they’ll do as-is. For what it’s worth the rudders are in far better shape than the rudders on our old Prindle 16. Looking back, I have to shake my head at what we were willing to put up with back then. I’d like to do a better job on this boat.

The tiller assembly is remarkably tight. One of the things I really can’t stand is looseness in a rudder assembly, and the loud clattering noise a loose rudder makes. Every bit of noise a sailboat makes while under sail is energy being dissipated as sound. That’s energy that’s not going into propelling the boat forward. A loud, loose rudder causes drag. I was glad to see how clean this rudder and tiller assembly is.

I used the rudder blades as my guinea pigs for compounding the oxide off of the boat’s gel coat. The gel coat on the boat’s hulls and rudders is heavily oxidized. I didn’t want to spend a lot of time re-working the hulls, so I got some 3M #09006 marine restorer and wax. This is a pretty fast-cutting compound, and does a good job of removing the oxide from the gel coat. It also contains a wax, which serves to seal the gel coat afterward. I plan to use this for the first two seasons we own the boat. After that I hope the condition of the gel coat is good enough that we can switch to a non-cutting treatment like a good 3M marine wax.

The tiller bars on this boat are apparently made from teak. The wood is in very good shape, but it will obviously need treatment before putting it in the water. I haven’t decided which route to go with this yet. I’m loathe to varnish it if I can avoid it.


The hulls are actually in better shape than they should be, considering the age of the boat and the conditions under which it was stored. Below deck the gel coat is heavily oxidized, but it’s largely intact.

That’s not entirely true. There are some pretty good scratches I’d like to grind out and re-gel coat, and there are a couple of impact marks I need to grind the gel coat off of so I can check the condition of the underlying fiberglass. On the bottom of one hull it looks like the gel coat had blistered when it was applied (which wasn’t all that uncommon at that time), and the blisters wore through, leaving hundreds of tiny pinholes. There’s an underlying coat of gel coat that is intact, but I’d like to address this at some point. This will be a major deal to do, though, so it’s not high on my list at the moment.

Above deck is another story. The gel coat there is utterly shot. I tried compounding some of the real problem areas, and I can’t get a decent finish on it. This was the first real roadblock we ran into.

A Quick Aside

When doing any sort of restoration, one of the key questions you need to ask is this: How far are you going to go? This is not a light question, and there’s no one right answer. For example, if you pick up a classic 1965 Ford Mustang, are you restoring it to factory condition so you can take it to car shows? Or road-ready condition to be a daily driver? Or are you going to soup it up beyond all recognition and blow the doors off unsuspecting rivals at the track? Each of these places different requirements on the restoration job. Factory original means you may spend months hunting down original parts or making perfect replicas. It may delay work on the car for years, though when you’re done you’ll have a truly unique machine. Getting it ready to be a daily driver may mean you skip that process for a lot of the parts, and order out of one of the aftermarket Ford parts catalogs. You won’t have original, but you’ll have functional. (And in many cases you’ll have something that performs better than the original!) And in the last case, of course you have to ask yourself why you bought a classic car if your intention was to rebuild it into something it never was to begin with.

Back to the Hulls

In our case we want a boat we can sail, not one that will be 100% true to the original. There’s no fleet of Pacific Catamarans out here to race, so we don’t have to keep it stock. Heck, there’s no fleet of catamarans out here at all, so we don’t even have to keep it true to a handicap scale. Our youngest child is eight. By the time she’s eighteen and moving away from home, my wife and I will be in our fifties. By all means I plan to restore the gel coat on the bottom of the boat as much as possible. Not because it’s original, but because that’s one more major overhaul I don’t have to do. But doing that for the top deck would be an enormous undertaking. There’s just no way.

Instead we’re planning to repair as much damage as we can using West Systems epoxy, prime, and paint it with a good quality top deck polyurethane paint like Interlux. I don’t have the facilities to spray (nor do I have the personal protective equipment to pull that off!) so we’re planning to paint by rolling and tipping. In the end the color of the top deck probably won’t match anything else on the boat. But it’ll be water tight, it’ll look nice, and it’ll be easy to maintain for the years we plan to own the boat.

Sheets, Roller Furler, and Traveler

As I mentioned earlier, the lower half of the mainsheet hardware was shot. I’d love to refurbish those blocks, but I don’t know how likely that is. Meanwhile someone was selling a 7:1 mainsheet off of a Hobie 18 on Ebay, so I bought it. Similar lower blocks, and with the addition of a bail on one of the upper blocks, those are identical as well. It should bolt straight on.

The mainsheet traveler is another story. It’s a 3:1 compound system, which another Pacific Catamaran sailor told me was necessary in order to change the traveller setting while under sail on this beast. One of the cheek blocks in the 3:1 system was seized, so I replaced both with new Harken blocks. The holes these bolt into on the traveler were wallowed out, so I’m planning to re-machine the holes and add Helicoil inserts to bring them back to nominal size (threaded #10-32). The wheels on the traveler are worn as well, to the point where it likes to lock up if there’s no upward force on it. I’m still deciding whether to build all new wheels for it, or to compensate for this some other way.

The foresail system is simply a mess…

Well, not entirely. The roller furler is intact, and rotated freely when we had the mast up.

Roler Furler

The rest of it really is a mess.

Initially, I couldn’t even figure out if the hardware we had was for a jib or a spinnaker. Turns out the foresail on the Pacific Cat is closer to a Genoa than a jib, which caused some of the confusion. The other call for confusion is that the Pacific Catamaran, unlike most beach cats, has a hard deck.

Deck Layout

My only experience with beach cats up to this point was a very decrepit Hobie 14 and a remarkably nice Prindle 16. Both of these had trampolines, and the jib sheeting hardware on the Prindle 16 was built around this idea. The blocks and cam cleats for the jib lay on the trampoline just rearward of the side stays. When I looked at the deck on the Pacific Cat, I didn’t see anything that even remotely resembled the sheet blocks from the Prindle.

It wasn’t until we stepped the mast and my daughter and I measured the foot of the jib and the lines attached to it that we figured it out. The blue tape just in front of the side stays in the photo above show where the clew of the foresail will come back to when sheeted in. It actually extends aft of the mast! It’s an honest to goodness Genoa! The clew of the sail comes down right around where the jib sheet blocks are on the Prindle. At that point I knew they had to be somewhere aft of where I was used to seeing them.

Next, we found something curious. On the Prindle’s jib, the forward blocks of the jib sheet are attached directly to the sail with a single shackle. The sheets run through these blocks and back to the rearward blocks and cam cleats. On the Pacific Cat’s Genoa, though, there were substantially long lines between the clew of the sail and the forward blocks of the jib sheet. We measured that line length and put a second set of blue tape marks on the boat to indicate how far back those extended. They’re visible in the photograph above, almost at the back of the cockpit!

What I thought were spinnaker blocks on the rear wall of the cockpit are almost certainly the rearward blocks of the foresail sheet! Even more strange, it looks as though the sheets then run forward to the base of the mast, where there are the remains of some pivoting blocks with cam cleats.

As I said, it’s a mess. But at least now it’s a mess I can sort out and eventually address.


This is where the story gets more depressing. The trailer is solid, but it’s also completely covered in rust. Introducing it to a salt water environment is just asking for it to be converted entirely into rust. So before we take the boat anywhere near the ocean, we need to strip what paint remains, rust-treat the bejeebers out of it, and paint it with rust-resistant paint.

To make matters even more interesting, the trailer was never finished. I have all the parts I need to build the upright at the front of the trailer to support the mast, but all it is at the moment is a collection of cut steel bars. They need to be welded together. Then they need the same rust treatment and painting the rest of the trailer needs.

The trailer is a project in its own right. Unfortunately it’s one I have no other way to accomplish except to knuckle down, learn to weld, and get busy.

The Plan

My to-do list is currently over a hundred items long. I’m banging out a couple each day. Progress is rapid, but there’s a long way to go before we can take the boat out on the water. The plan is to keep grinding away at the list until I run out of things to do. With time, perseverence and back-breaking work, I should have it done by the time the kids are out of school for the summer. With a little luck I might have it ready before that.

– Tom

Posted in Sailing | 2 Comments »

The Ugly Duckling Project

Posted by Tom Benedict on 21/03/2012

I managed to pare down my project list. Not by getting anything done, mind you, but by pruning it with a machete. In short, I bought a boat.

To be fair I have been looking for a boat for some time. I used to sail a Prindle 16 beach cat that I co-owned with two of my friends. It was a tremendous amount of fun to sail, but when our family moved to Hawaii we had to leave it behind. That may sound odd, considering we moved to an island in the middle of the Pacific, but the practicalities dictated our decision: We bought it for $600, and it would’ve cost several thousand to transport. So for years we were boatless. Still, each time we went to the beach I found myself watching the sailboats as they sailed by, just wishing. A couple of months ago I knew the time had come. The kids were older, and we’d waited long enough. We had to get a boat.

Every boat is a project. Even a new one. There’s an old saying that the word “boat” is actually an acronym: B.O.A.T., or Bring Out Another Thousand. It’s not far from the truth. We dodged that bullet more than we deserved with our old Prindle 16. I figured we spent maybe a thousand total the whole time we owned it. A new main halyard, a new trampoline, a new trap harness I bought for myself, wheel bearings, wheel hubs (don’t ask), license, and registration. It adds up. So when I started looking for a boat out here in Hawaii, I knew I would get in over my head to some degree.

I didn’t disappoint myself. I’m in over my head. The boat I found is a Pacific Catamaran 19, or a PC-19 (not to be confused with the P19, which was made by Prindle). It’s a bit of an odd boat in the beach cat world because there is no trampoline. It has a hard deck. Because of this it’s also several hundred pounds heavier than a comparably sized Hobie, NACRA, or Prindle. By way of comparison, the Tornado, a 20′ boat used in the Olympics, weighs over 200 pounds less than the PC-19, and is a foot and a half longer. Go figure. It’s slow by today’s standards, but it makes a comfy day sail boat. Perfect for sailing with kids.

The boat is in what’s affectionately called “project condition” or “beater condition”. The best translation I’ve found for this is a quote from Firefly:

“You paid money for this, sir? On purpose?”

The good news is almost all the bits are there. The mast is straight, the halyards are in mostly good shape, and all three sails are in reasonably good repair. (Yes, three sails: two mains!) The list of immediate needs is actually quite short: Almost all the pins are missing, and a couple of shackles may need replacing. Most of the cam cleats are jammed, and could probably stand being replaced. The larger main needs to have its top plate re-riveted. But other than that what it mostly needs is a firm hand with a scrub brush and a lot of TLC. I figure a month of evenings and weekends should see it ready for the water.

The trailer is another matter. It needs rust treatment, painting, lights, a license plate, and a tow kit for my Jeep. (Yes, I have a Jeep with no trailer hitch. Whatever.) This may take longer than the boat itself. Figure two months.

For now I have only two projects left on my plate, aside from what I do at work. The first is the Worldwide KAP Week 2011 book, which has been on my wife’s plate (and hence mine) since last year. I want this wrapped up and published in the very near future. The other project, of course, is the boat. For now, everything else gets set aside.

There is very little information available about the Pacific Catamaran 19. I haven’t found any online manuals, and there are precious few photographs. I can’t remedy the former, but I can certainly address the latter. I plan to make before, during, and after photos of the boat as I go along. And of course once it’s out on the water I plan to photograph it as much as I can. Eventually I’d like to fly a kite off the boat and join the ranks of the sailing KAPers. But that’s a project for another day. For now, getting it seaworthy is project enough.

– Tom

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An Overabundance of Projects

Posted by Tom Benedict on 15/03/2012

A couple of things have come up recently that sparked a whole slew of projects at home. Unfortunately I’m also right in the thick of a major project at work, so I’m feeling a little overwhelmed. But… such is life.

One of the projects is a change to the 6WD camera project I was working on late last year and the first part of this year. We’re trying a change in the camera mount that will lower the center of gravity and give the operator much better options for pointing the camera. This will mostly be accomplished using components from Brooxes, so it’s right up my alley. Back in my happy place! The only non-Brooxes component I’m planning to use are a set of Servo Blocks from Servo City.

Servo Block Built

This is a component I’ve been itching to play with for some time, so again, I’m back in my happy place. One question I want to answer is whether a single metal geared servo and a set of Servo Blocks components can be used to build a HoVer axis on a KAP rig. I think the resulting axis will be lighter and have less end play and angular play than the HoVer axis I built out for my A650 rig:

Subtle as a Dump Truck

I miss having the HoVer axis on my DSLR rig. My hope, of course, is that I can add a third axis to my DSLR rig. Of course this will add weight, but… such is life. My only concern at this point is the height of the unit and the space requirements the DSLR puts on the rig. It might simply not fit. Only one way to find out!

All of this would’ve been enough to keep me going for a while, but then I saw this on Flickr from fredkap88:

It’s a really cool self-contained AutoKAP rig where all the electronics fit up inside a rotating enclosure that’s part of the pan axis. It’s a super clean design. Looking at the video of it moving, I expect it’ll be a real joy to use in the field. Seeing it just got the designing gears going again!

There are a couple of real advantages to having a dedicated rig like this for panoramas. The first is that you can shave every unnecessary gram from the rig and camera. The second is that operationally, things become much more simple and much more repeatable. It’s possible to do panoramas with a conventional general-purpose KAP rig, but it requires fair attention to detail to make sure there is sufficient overlap between frames, that the overall coverage is sufficient, etc. With a dedicated rig, panoramas just happen. The real joy is picking out the best of the best once everything is back on the ground.

Coming right on the heels of this, I might have the opportunity to work with someone who has a potential market for aerial panoramas. So there’s some motivation to see what I can do in the short term rather than leaving this on a back burner the way I sometimes do.

I’m taking the next four days off. Some of that I hope to spend doing KAP at more photogenic locations than I’ve been in the habit of visiting recently. Certainly a good bit of that will be spent working on the modifications to the 6WD camera project. But a good bit of that will also be given over to rig development for doing panoramas with my T2i. I hope to have good things to share later in the weekend.

– Tom

Posted in Engineering, Kite Aerial Photography, Photography | 1 Comment »

Changes to the Video Down-link Hardware

Posted by Tom Benedict on 05/03/2012

From 2007 until a couple of months ago, I’ve done kite aerial photography using an RC radio to control pan, tilt, and sometimes yaw on a camera rig suspended from a kite line. Aiming has been done by looking at the camera rather than by looking through it. And for the most part this has worked well. I did some good photography, made some good panoramas, and had a truckload of fun flying kites.

Kiholo Bay

A number of events over the past year or so have made me want to try using a video down-link. I ordered the hardware, found out I needed a ham radio license in order to use it, studied for my license exam, passed it, and finally built a video down-link for my rig. It wasn’t completely smooth sailing, but it worked. More to the point, it worked well enough to convince me this is a direction I’d like to go. So I set out to fix the problems I’d run into and re-design the system so it fit in with how I like to do KAP.

My style of kite aerial photography is a little rough and ready. Everything goes in a backpack so I can hike in to wherever I need to be. When I’m flying I can tolerate holding a remote and a winder, but that’s it. Most of the time I’ll clip the winder off to a waist strap so I can have both hands free to operate the remote. I like to keep an eye on the kite. If things get rough, I want to be in a position to drop my transmitter on the ground so I can devote 100% of my attention to the kite. This has saved me from losing both kite and camera in the past, and will continue to save me in the future. I have stayed with this philosophy since I started doing KAP in 2007, and I see no reason to change.

When I added the video down-link to my setup, I wanted it to follow this same model: All of the ground-side video hardware had to fit on my RC transmitter. No extra stuff. No batteries in the backpack. No stray cables to prevent me from dropping some or all of my gear so I can deal with an unruly kite. All of the air-side video hardware had to fit on the KAP rig as discretely as possible. Once installed, I had to be able to wrap both KAP rig and RC transmitter up in cloth and shove them into my backpack for transport. If things went wrong in the field, I had to be able to drop the RC transmitter and ground-side video gear and not have it break. Everything had to be robust enough to handle this kind of treatment or it wouldn’t survive my style of KAP.

I came up with a good arrangement.

KAP Rig as of 5 March, 2012

The monitor is hard-mounted to the RC transmitter. It has a 1/4″-20 socket on the back, which made this easy. The hood is formed from some ABS plastic I had in the scrap bin. The 5.8GHz video receiver is attached to the back of the transmitter with industrial strength Velcro. I’m not 100% happy with the wiring between the monitor and the receiver, but it’s at least neat and tucked out of the way. All of the ground-side electronics are powered off the same battery supply. At the moment this is 8xAA Eneloop rechargeables located in the RC transmitter, but a future plan is to replace this with a LiPoly transmitter flat pack battery. For now it works, and appears to give hours of service. When the time comes to upgrade, I already have a battery picked out. (Thanks again to Bill Blake for pointing me in the right direction on batteries!)

The KAP rig has the video transmitter mounted above the RC receiver, on the opposite side of the rig’s aluminum frame. I am not convinced this offers sufficient RF shielding, but for now it works. A single cable runs between the video transmitter and the camera. A second cable made by James Gentles runs between the RC receiver and the camera’s remote shutter jack to remotely trigger the shutter. When installing the camera, these are the only two cables that need to be installed. Keep it simple.

5.8GHz Video Antennas

I replaced the stock antennas on the video transmitter and receiver with a cloverleaf and skew planar wheel, respectively. There were custom made by These are right-hand circularly polarized antennas. They offer a reasonable amount of gain over a simple half-dipole, and also offer some amount of rejection for linearly polarized signals. As an added bonus, PNPRC tests their antennas for good SWR match at 5.8GHz. Put it all together, and they’re a nice upgrade for a video link system. I haven’t had a chance to test these in the air, but already on the ground I can see a benefit.

These antennas are somewhat fragile. One was slightly bent during shipping. Easy enough to bend back, but I can see that some form of protection will be needed when I’m using them in the field. For the moment I’m removing them in order to pack my gear. As a longer term solution I’m leaning toward some radomes. Considering the size of the antennas, ping pong balls might be the perfect size.

For early tests I powered the air-side unit using a separate 9V battery. This was bulky, it added weight, and rechargeable 9V batteries have nowhere near the current capacity of an alkaline 9V so I was forced to use alkalines. Not my favorite solution. But it worked well enough to convince me the video down-link was a good idea.

More recently I completely re-vamped the video power system on the ground and in the air:

KAP Video Switch

Here’s how the new setup works:

The ground-side unit has a single master switch. When the RC transmitter is powered off, everything on the ground is powered off including the video hardware. When the RC transmitter is powered on, power is also available to the ground-side video hardware (monitor and receiver). Power to the ground-side video hardware is controlled using the quad-pole double-throw switch shown above. One of the poles is used to switch the power to the ground-side video hardware.

The other three poles are wired to a pair of 5k potentiometers. This lets the switch toggle between two fixed set-points for an RC channel at the same time it is controlling power to the ground-side video hardware. When the ground-side video hardware is powered on, that RC channel goes to 2.0us timing. When the ground-side video hardware is powered off, that RC channel goes to 1.0us.

On the KAP rig, the RC channel associated with the switch is wired up to an RC MOSFET switch from Pololu Robotics. Above 1.7us timing, the MOSFET passes the rig’s Vbatt on its outputs. Below 1.5us, the MOSFET passes 0.0V on its output.

The output of the MOSFET is connected to a 2.5-9.5V variable boost regulator, also from Pololu Robotics. Powered by anything above 1.5V, it’ll output a fixed voltage that can be set using an on-board potentiometer. I set mine to 9.3V and plugged it into the video transmitter on the KAP rig.

The net effect of all this is that the RC transmitter has a single switch that can be used to control power to the video hardware, both on the ground and in the air. This opens up a method of doing KAP that saves on batteries, and very closely follows how I do photography from a tripod:

When I’m using a tripod, I like to scout a scene handheld first. Once I find one or more vantage points from which I’d like to do photography, I’ll attach my camera to my tripod, rough-position the camera, then look through the viewfinder to see where I need to move it to get the composition I’m after. Once I’ve composed the photograph, I’ll do a final focus and finally trip the shutter. Then it’s on to the next vantage point.

When I’m doing KAP, I can power off all of the video hardware and set down the radio so I have both hands on the winder while getting the camera to altitude. Once it’s at altitude I can walk the camera into position, flying it by eye the same way I have done since 2007. Once I think the camera is in position, I can power up all the video hardware and take a look at the viewfinder. If I need to adjust my position I can. Then I compose, focus, and trip the shutter. Then the video hardware goes back off while I walk to the next camera location. With the exception of the kite, it’s almost the same procedure.

From past experience I know I can use my KAP rig without video hardware for many hours in the field without running out of battery on the ground or in the air. Video hardware places an additional drain on the batteries of both the KAP rig and the RC transmitter. But by having the power switchable in this way, it’s minimized.

– Tom

Posted in Electronics, Engineering, Kite Aerial Photography, Photography | 7 Comments »