Finite element analysis

I'm clinging on to the top of Cangarda's main engine with one hand (the crocheted glove is a style thing) while leaning back to take this picture. The point of this exercise was to get a better 'grip' on the geometry of the cylinder head for a finite element analysis of the pressure forces. Our first cut at determining the stresses in the head was to assume it was a flat plate. A simplification that was ...simple, but clearly incorrect. The stress result was ~9600 psi for the test pressure, which for an old casting of unknown quality, could be too high...it could fail.

So, we made a 3D, virtual solid model of the head (omitting the stud on the top, which is probably not important).And, after applying simplified boundary conditions, subjected it to the virtual test pressure force.

This is a plot of the Von Mises "stress" for the test pressure. The result is that the predicted stress is actually ~3700 psi...a stress which is much less likely to result in failure.

I put "stress" in quotes since it really isn't a stress. It's a numerical way Von Mises, whoever he was, developed to combine the three principal stresses into single number, which he then compared to the yield stress of the material.

Cangarda Overtime

"Hola, amigos. How's it going with you? I know it's been a long time since I rapped at ya. I been trying get through a jungle of bullshit, but it grows back as fast as I can cut it down.."*

As all the homies know, Cangarda (and Jeff Rutherford) moved out in January. The marina is reverting to the swamp and fenland from whence it came. We have a semi-resident female sea lion now, which is in a way preferrable to yachts, boatbuilding and commerce. Our landlord (of whom I must speak in the gentlest terms, lest we be kicked out as well) evidently prefers it this way as only our office and a houseboat remain.

Cangarda's new berth is on a westerly facing end tie in the Richmond Marina (Marina Bay). It's a little exposed to the West, but they have some strong fenders out and it looks in pretty good shape.


It's in a picturesque spot (across the Marina from the old Ford assembly plant), and the docks and bathrooms are way better than at 320 West Cutting, but the boat is a full seven minutes walk from the gate, making it a time/management nightmare. Still, it's a veritable hive of activity there with the owner, captain, Jeff, Steve, electricians and assorted helpers on board, as well as three super experienced steam engineers laboring away, trying to make the thing run. Here's Chief Jordan and Gary upside down in the bilge...Pull up your pants fahcrissake!
Getting it to run is still problematical, but perhaps a bigger hurdle is getting the permission to run it at all. Steam boats have been pretty strictly regulated in the US since 1871 with the formation of the Steam Boat Inspection Service (merged into the Coast Guard in 1942). The law, still very much in force, regulates all vessels, even yachts, greater than forty feet in length with a steam pressure greater than 50 psi, i.e., Cangarda. In general, yachts are only subject to very weak oversight by the Coast Guard. As an example, a lunatic could quite well have the idea to build a fifty foot sailing catamaran, out of disposable plastic bottles, attempt to sail to Hawaii, and the Coast Guard would do nothing to stop him. But steamboats, even privately owned pleasure yachts, are subject to all federal regulations. Period. That's why I stopped by Cangarda on Friday.

The new boiler is hotter and more energetic than the original Almy, and is currently set to run at a high pressure. Although the boiler has been tested to the higher pressure, and the piping is rated at much higher pressure, the Coast Guard has no assurance that engine itself can withstand the higher pressure.

Here are the decorative covers to the cylinder head covers. Each cylinder, and the adjacent steam receiver, has a seperate, bolted head.


This is the head of the high pressure cylinder.
The complex shape of the head makes any simple analysis of the pressure forces a little dubious. Tomorrow I will put up some images of a finite element analysis of the pressure forces on the head.

*Jim Anchower, The Onion

Cangarda cangarda cangarda cangarda

Blow a gasket is a beautiful idiom, rarely heard today. As, "if I come home late, the old lady will blow a gasket." You can visualize those old Looney Toons...Porky Pig, Wile E. Coyote, Daffy Duck, heads inflating, turning red and live steam issuing out of their ears. Of course, the idiom originates with to steam technology.

Of course today internal combustion engines have gaskets too, but they're generally pretty good, being precisely manufactured from high temperature polymers, and inset into perfectly machined grooves. It's rare to have a catastrophic failure. Oh, the occasional hopped up race car blows a head gasket spewing hot oil on the track, but it can only spews as much oil as is inside the engine...a few quarts. In contrast, the head gaskets on olde timey steam engines are comparatively weak, and fragile. And when one blows, the entire content of the external boiler erupts through the gap until the brave engineer can fight through the steam and shut it off. Yosemite Sam with 453 F steam whistling out of the top of his head.

In this picture you can just barely make out Chief Pete Jordan exercising the whistle Friday afternoon. He was warming up the boiler prior to a celebratory trial in the Channel planned for Saturday. Well, evidently they didn't drain a cylinder or something, because they blew a gasket and couldn't go. Makes you wonder though...blow a gasket racing your Porsche around town, you just call the tow truck. What happens at sea?

To all the Cangardaphiles who have bombarded me with questions as to why, for gods sake, is it not running yet, here is a picture of Henry I took today wiring up the automation panel. Maybe you can zoom in and check out what's inside that box (damn the resolution of this picture) -- there are hundreds of terminals for valves, senders, and gauges needed to control the steam plant and engine. Only about a third of them are hooked up. I'll take a closer picture tomorrow before he gets to work.

Here's a final note. My neighbor, Jeff Rutherford, who restored Cangarda, has a new webpage. Check it out.

Cangarda all the time

The film makers have posted a new trailer:
http://www.kailuna.com/ultimate_restorations.html
It looks all done and ready to go -- oh, hang on...I guess it's still out there.

Schooner racing

Is the name of this vessel Virginia or Schooner Virginia? Better check the website. Aw, I knew the answer, since we designed and built it. Every plank, every screw, was designed, planned and built by Tri-Coastal Marine...that is, us. While it may belong to others now, it still is our creation.

Virginia winning the Govenor's Cup in Gloucester

Here are the race results for Class 1:

You can hardly read it - there a very close margin at the finish...Virginia by 26 seconds over American Eagle. Yet that is Victory! Unfortunately, the thrill of being top schooner was short lived. Last weekend Virginia was creamed by Spirit of Bermuda in the multi day round Prince Edward Island race, taking a distant third (Pride of Baltimore II was second). Defeat is hard enough, but the purse for this race was $40,000! I don't know if that was $US or Loonies...either way, it's real money. Glory is great, but money is mo' bettah.

The main problem with any kind of competition between sailing vessels is making it fair. Boats that are built to the same class, e.g., Echell's, Lightnings's, J-24's, etc, are all nominally identical and compete equally, winning by superior skill or luck. Roughly similar vessels often race on the basis of handicap. Handicapping or rating systems are based on physical properties of the vessels, previous performance, or the corrupt judgement of inept race organizers. Virginia and Pride are true historic replicas built with historically appropriate technology. Spirit of Bermuda looks like it may have been based on something old, but is really just a big, cold molded sailing yacht. Fair? Hardly. The only truly fair result is when one of our designs wins. (and all prize money is awarded to the Andrew Davis Personal Aggrandizement Fund!)

Cangarda under way!

In answer to all the angry emails demanding information, I'm now doing continuous coverage on Cangarda.

[Breaking news] Sunday the 24th Cangarda raised steam and maneuvered for about an hour in the Richmond Ship Channel. The owner was at the helm and Chief Pete Jordan (ably assisted by Alex David of Maritime Controls) was controlling the boiler and engines. I missed the whole thing (windsurfing)...if anyone has a photo of it under way, email it to me and I will post it here.

Pete came in this morning, jonesing for coffee, and reported that the engines and propulsion worked well. He doesn't have any idea where they actually went, because he and Alex were so busy controlling the boiler, furnace, pumps and engine that they couldn't even stick their heads out the companionway.

As I wrote previously, the intention is to automate much of the operation; however, essentially none of that has been done yet. The electricians are not close to finishing their work (the vessel operated Sunday with a temporary load center), and until they do, Maritime Controls can't hook up and calibrate the dozens of valves, gauges, etc required for normal operation.

So in answer to all the emails about Cangarda's schedule...she still has a long way to go. I will keep you posted.

Lake Champlain Sail Ferry

Here's an odd little vessel we designed and built in 2001:

Weatherwax from port quarter

Ha, ha. The first caption was fake -- it's double ended, and the rig is on one side (the leeward side, duh)! It's stange, but we didn't just invent this thing up in a caffeine fueled weekend, in fact, the double ended sailing ferry is a historic type that was unique to Lake Champlain. Bordered by New York and Vermont (and maybe Quebec), the prevailing wind on the long and narrow lake is along its narrow north/south axis, which let the double ended sailing ferries reach back and forth across it.

People used to wear nice hats

Weatherwax is licensed by the USCG to carry passengers and now lives at the Champlain Valley Transportation Museum. Find out more about the vessel.

In the first sentence, I wrote "we designed and built...", which I suppose is strictly true, but doesn't give Douglas Brooks, the project manager, the credit he deserves for getting the contract, motivating the project, and then actually building ~90% of the vessel himself.

Douglas caulking the bottom

Since the fery project, he's kept himself busy. Here's his latest creation, a glued lapstrake replica of a Henry Rushton Catboat.

Under way

Douglas is an interesting mix of scholar and practical, Yankee boatbuilder. Without a doubt, he is the living expert on the tarabuine (japanese tub boat). Go to your local bookstore and ask for his book, The Tub Boats of Sado Island: A Japanese Craftsman's Methods. Yeah, well that's supposed to be a joke too...let's say you won't find it at Barnes and Noble, but you can get it through his website.

As far as being an excellent, completely no-fake, Yankee boatbuilder, I will now bestow upon him the highest praise that a Yankee boatbuilder can give to another, "Boy, you are clever. Why you are good enough to make a set of false teeth."

CN 55 Eager

Fiber reinforced plastics, FRP, transformed boat building more than any other single technology. Prior to FRP, small yachts were built individually, mostly from wood. The earliest fibers used in FRP were fiberglass, which was discovered serendipitously by Owens Corning in the 1930's. The first frp composites production molding followed soon thereafter. Although today frp can be made with fibers made from different materials (eg., graphite, polyester, boron, etc), fiberglass is still used as a shorthand for anything made from frp.

'Fiberglass' was the perfect material to meet the nascent demand for mass produced pleasure craft back in the 50's. The first successful molded frp production sailboat was the Pearson Triton, which started production in the early 60's. Twenty eight feet long, the Tritons were relatively small and easy to mass produce (there are over 700 of them), and were so solidly built that most of them are still around today (in fact, Bobby Botha, one of the workers on the Cangarda project, recently attempted to single hand one back to Kiwi). Like the Triton, many other old production boats were very solidly built...they still look great and can function just as well as they did when new. There's even a name for them, Plastic Classics.

Eager (ex-Lutine) is undergoing a total rebuild in Jeff Rutherford's yard (which we call Tire Barn for the faded logo of a former tenant). It is a Camper and Nicholson 55, one of the first large, production fiberglass sailing yachts built in quantity. The Nic 55 was a popular and successful ocean racer and cruiser through the 1970's and has a cult following today. Unfortunately, Eager, like many yachts of that era, was built with a plywood core in the deck and cabin trunk ... it's amazing it lasted as long as it did. Hence, the vessel is getting an all new deck and cabin. Here's the deck mold, which Tony and the crew built using the old deck as its core:


With the deck removed, it's a whole lot easier to build a new interior from the top down, rather than passing every little bit in through the companionway. This is how any new custom yacht would be built today. Unlike a house where the roof is put on as early as possible, the deck is put on after the interior, wiring, plumbing, mechanical systems, etc are largely complete.

It will has entirely new interior and deck arrangements. New bathrooms, new staterooms, new engine, mechnicals,new carbon rig...everything new, new, new. Here's our new exterior arrangement. Underbody will be unchanged, except for a new (improved) rudder and skeg.

Is it worth it to renew/rebuild a plastic classic? Well, people choose to do different things with their money (some people may choose to pay the rent, or buy canned goods and medicine instead), but, in spite of the new rudder and rig, it's probably not if measured by cost/performance measure.

Pirates of the Caribbean

One of the many interesting jobs we've had recently was designing the ships for Pirates of the Caribbean. We still get numerous requests for lines, detail drawings, etc of Johnny Depp's flagship Black Pearl. Of all of them, it is only truly functional vessel we designed for the show. But, it's fake too.

There are no detailed drawings of the whimsical 18th century, round bottom, wooden pyrate ship, because there is actually a 120' steel OSV (offshore supply vessel) inside of it. This is what we started with:


The idea was to take a fully functional, working ship and stuff it inside a Black Pearl shell. First we created the concept hull:The Sunset was a 1970's era stout and well maintained little ship, carrying cargo in the western Caribbean...that is until we wrecked it. We made the new hull considerably bigger than the vessel in Pirates I, but still had to trim off the stern as shown in the pfoto above. Here's a picture of Sunset immediately after being hauled at Steiner Shipyard. Note the framing for the new watertight sponsons.
Steel framing was attached to the modified hull, and a cold molded shell fastened on top. This just after it rolled out of the building shed. Sunset's bottom with propellers, shafts, bearings and rudders sticks out the bottom.

Check out the hydraulic crew door -- I think that's the coolest part of the boat...turns out it was the cheapest, easiest, safest way to transfer the equipment, food, stars and makeup onto the Pearl. Very 18th century.

I'm posting this final picture for all those who don't believe that we don't have detailed rigging plans for the vessel:

Look...there is no rig! It's truncated at the fighting tops...everything above there was CG. Well, if that part is CG, you may wonder (as I did) why didn't they animate the whole thing? One of the fascinating things about working on this project was to see how the studio determined what would be real and what would be animated...it depends how long it will be on film. If some part is going to be on film more than a few seconds, its still cheaper to build a full size thing then it is to create a virtual thing...I guess carpenters get paid less than animators.

Sunset/Black Pearl turned out pretty well, and as I wrote, fully functional. Immediately after it launched, it navigated 2000+ nautical miles from Bayou La Batre down to the Eastern Caribbean, then back up to the Bahamas. As far as I know it's now stored somewhere in Ensenada, Baja California.
_________________________
Cangarda update: I see there is an ongoing thread on the WoodenBoat design forum

Homemade boats

My daily blog has deteriorated to ...monthly? It's windsurfing season now, and my productivity, always low, has declined to near zero. Today is the first day of summer and there is no wind, but rather than working on something useful, there's a mighty vesicle next door that I had to post some pictures of.


Looks like someone found a sunken, dented and rusted push boat stern and decided to marry it to a new bow:

Human ingenuity! I will keep an eye on this important project.

Ah crap...am I being a neg-head downer again? That's the only thing keeping us from greatness -- my lack of a positive attitude. A couple of years ago while I was stomping around the office, wailing that a well known (but lesser) designer got a commission for yet another fabulous mega sailing yacht. An employee (who had previously worked for that lucky designer) noted that he never had anything bad to say about any boat (or any subject for that matter).

"And what inference should I draw from that!?", I asked the (now former) worker. Hence, my summer solstice resolution is "Never tell a man his wife is fat, his child is stupid or his boat is slow (because he already knows and doesn'w want to be reminded of it)". Starting now, a new positive me. So, to the proud owner of the vessel next door -- excellent concept, nice workmanship, and my sincere wishes for your prosperity and success!

Chuck and others have asked for an update on Cangarda. Looks like they're stuck here for at least the summer and back to a Skeletor crew. The owner had raised expectations (and here) it would get to New England for the summer yachting season, but ("positive, positive, try to stay positive...") was unable to meet that skedyool due to (my) weakness, bad posture and lack of belief.

As I wrote previously, Cangarda has raised steam. Chief Jordan was here for about six weeks and is a miracle worker. The main engine turns and shifts beautifully (amazingly rapidly). There was some problem with the air pump for a while, but now all the auxiliary engines work as well. Critically, Pete raised steam by hand. Of course, that's how they did it a hundred years ago...shovel in the coal, open the dampers and away it went. However, there's nothing simply about the operation of the renewed vessel. It is dependent on automatic combustion and boiler controls.

I don't think anyone, even the greatest neg-head downer (uh, that would be moi) anticipated that the process of automation would be so difficult. All the valves, sensors, switches, et cetera for the combustion process will be controlled remotely. As far as I can tell, not a single connection has yet been made between these devices and the controller.

During the last few weeks, Pete bypassed the automatic devices and fired the boiler by hand; however, the process is not sufficiently reliable or efficient to actually go anywhere. Also, because the valves are not really laid out for manual operation, it's possible to inadvertently have a furnace explosion when lighting a burner. Indeed, the owner himself caused one two weeks ago...luckily no one was hurt.

Hey, now that's positive!