A DIY Rocket Stove Smoke Hood

 

Eco-Zoom Rocket Stove with DIY Smoke Hood

Somebody who claims to speak for the ‘hood don’t need no private jet.

– Chuck D

A DIY Rocket Stove Smoke Hood

About half of the energy in wood literally goes up in smoke, and with it, a good deal of our own! If the smoke can be burned, efficiency nearly doubles. The corollary is that only half as much fuel produces a given amount of heat.

Rocket Stoves were developed as a low-tech solution. At their heart is an L shaped, insulated tunnel, wide open at both ends. Fuel is fed horizontally, oxygenation and combustion burn hot at the crux, and what little smoke is left is pushed vertically, up and out the top. Typically, a pot directly atop the stove absorbs heat from the hot, gaseous outflow for cooking.

We’ve been using an EcoZoom Rocket Stove for years as a nearly smoke-free, otherwise open deck fire for outdoor cooking in hot weather, an evening blaze in nice weather and to heat metals for various projects (it easily takes ferrous metals to red-hot). It runs on limbwood from about thumb to wrist size, the former for cooking and the latter for longer, more subdued heat. In short, perfect for easy wood-gathering, especially as we age..

In planning MUSTELID, we hoped to bring this marvel indoors for cooking and heating. It requires far less wood to gather, dry and store within her small volume. Being insulated, wood can be dried directly alongside the stove, warm but nowhere near wood’s flashpoint (we can touch the stove sides without burning!).

To bring it indoors, we must gather and direct combustion gasses outboard, like any other onboard stove. The solution is a smoke hood fit snugly over the stovetop with a stack, which has the extra perk of increasing the cooking surface area. We wanted one more feature… we wanted to easily install and remove the stove for outdoor use on deck or ashore. So we went for a swing-up, cantileverd variation.

This called for some head scratching…

Note (black) fire-blanket to protect carpet from sparks, 

Grate spacer for airflow under,

Ash tray…

Whole thing slides aft behind bulkhead lip

And between heat / splatter shields.

Near end swung up to remove / install Rocket Stove

Not to Scale

Smoke Hood Elements

At it’s simplest, the hood is a flattish box made from sheet metal (in our case, stainless steel from and old stove’s grease trap… a heavier top plate has better thermal mass for cooking, if available. A large hole in the bottom fits closely over the Rocket Stove top, while a smaller hole in the top has stovepipe fit into it, which leads to a standard deck-jack and smokehead. If you leave the stove in pace, this is all you need.

For a swing-up top – allowing removal of the stove – we broke the hood into two boxes, each with an open end:

1. The far box is fixed (in our case to bulkhead and flanking heatshields), with the flue let into its upper surface. Its near end is open, with rounded shoulders and an under-lip. This part is female, slightly larger than the second part.
   
   

2. The near box is cantilevered (stops may be additionally fitted to help support heavy pots). Its far end is open, with a partial rounded shoulder fairing to 45deg… extending an over-lip, while the angled section limits upward swing. This part is male, slightly smaller than the first part. Insert its open end into the female’s until their respective hinge-pin holes align.

Other parts:

• The long hinge pin (alternatively, short, opposing pins) are let through paired holes centered on the shoulders. If it binds while swinging upward, grind away from the lower male shoulders till clear.
  
  

• A vertical smoke collar can be used around the stove-top cut–out (not sure it’s necessary). We used a strap of sheet metal, its edges doubled over just short of its outer mid-line (result about one inch wide) and tabbed around its outer mid-line (tabs bent alternately, slightly away from cut-out). When pressed into place, it ‘snaps’ in to lock. It works best to cut the tabs before bending.
  
  

• Rims, rails, bars and what-have-you may be added to secure pots while cooking underway. In our case, we added a low front rim and let that and tall heat / splatter shields along each side contain pots. Watch for swing-up clearance.

Notes:

• Any gaps allow air to be drawn into the hood. The closer the fits, the more energy is available for cooking and heating. Once the stove is drawing (seconds) there appears to be no leakage, even from wider gaps. We didn’t use gaskets, but they can’t hurt.
  
  

• We sized our male part to be 1/16in smaller than the female’s inside dimensions. Given our crude techniques, we managed between 3/32in and 1/8in. So long as it slides in without undue forcing and the gaps are small, it should work fine. Thermal expansion binding isn’t a problem as we only ever move it out once cool.
  
  

• In both cases, the lips should overlap the opposite part to help close the gap and contain ash. Small tabs may optionally be bent along single edges to help minimize warping with heat.
  
  

• Sizing can be more or less according to your available space. We sized around our frypan plus our small teapot, to cook and heat water at the same time.
  
  

• The smokehead can be lower to the deck than is usual. Although it does induce some draft, Rocket Stove’s generate expansion in their combustion chamber, and actually push gas about 40ft. Still, an efficient draft smokehead hedges our bets in some gnarly conditions.
  
  

• We didn’t have a brake (sheet metal bender), so clamped sheets over a piece of sharp-edged hardwood, then hammered it over. Cutting was with a thin-wheel grinder and touched up with a mill file. We used bent tabs with (copper/stainless) pop-rivets to join. Wear gloves, eye, ear protection and work safe!

Looking Ahead

One of the intriguing possibilities with Rocket Stoves is to make our own from a substance that insulates, absorbs and radiates thermal energy. In other words, which acts as a thermal mass or ‘sink’. Such are easily made from brick, firebrick, concrete, clay, cob and other materials. 

Perlite (pumice) is a light, inexpensive insulator, and can be mixed with concrete for a lightweight aggregate with decent thermal mass. The combustion chamber can be lined with refractory clay. A thick, steel cook surface is easy to install over a lipped smoke chamber for a full sized stovetop / smokehood. Sand makes a good gasket between plate and stove. Alas, this doesn’t sound very portable!

But we keep on thinkin’.

5VDC Revolution for Smallish Boats?

MUSTELID's 5/12VDC Hybrid Electrical System
(Lithium Ion Batteries are HAZMAT, so we went with Lead/Acid)

 

An immense effect may be produced by small powers
Wisely and steadily directed.

-- Noah Webster

5VDC Revolution for Smallish Boats?

A while back I wrote about a simple 12VDC system, here.

For a very long time, 12VDC systems have been the go-to foundation for small vessels. There's been a host of products available both in marine and RV/auto markets that meet all the needs of the small scale sailor.

But there's a quiet revolution boiling along for the last decade or so, and it's reaching maturity. I'm speaking of USB charging, 5VDC systems. 

From charging arrays (PV) to controllers to lightweight, high-capacity batteries to products ranging from smart phones, laptops, GPS, VHF, depthsounders, navlights, cabin lights, spotlights... all has become available at generally lower up-front costs and considerably lower draw.

Many of these devices have rechargeable, onboard batteries, each of which can contribute to total power storage, eliminate runs of wiring and reduce the size of a central battery. USB 'hubs' serve as power strips for centralized charging and flexible power supply.

If your vessel is already set up for 12VDC, it's likely most economical to stick with it, or possibly hybridize with a USB hub to handle new acquisitions. 

But if you are outfitting a small vessel, particularly in the micro-cruiser range, The small footprint and low draw of 5VDC is well worth a look!

The Payson Butt

 

Payson Butt

(Used by permission)

My butt may be big, but there's no song about your flat one.

-- Internet Meme

The Payson (Fiberglass) Butt

The Fiberglass Butt - shown in plan below the main illustration - has become a common means to join plywood sheet edge-to-edge, and works as well for patches.

Of it's provenance, Dave Carnell writes:

In 1986 I wrote about the joint in Small Boat Journal. About the same time "Dynamite" Payson wrote in Boatbuilder about a similar joint concept. Years later I discovered that Joe Dobler had used the principle well before our publication, as had Jack Chippendale in England.

This method includes variants in which the ply is step-layered to accommodate the fiberglass at or below surface level.

Payson produced this great illustration for a variant that's come to be known as the Payson Butt. He was kind enough to grant permission to reproduce it, back before the internet. 

Recently I was shocked to be unable to find it posted entire (uncropped and showing the standard butt), so am putting it out now. This version has been lightly edited to clarify text that had been poorly digitized.

The Payson Butt was proposed (originally, so far as I'm able to determine) that the 'step' depression can be done as a ground-out dip, with the addition of the smoothing technique shown above.

According to Payson, the full method is unnecessary for strength (the plain fiberglass butt is sufficient), but smooths the hull for an aesthetically smooth finish.

Either way, it avoids simple-but-intrusive buttstraps and labor-intensive and sheet-shortening scarfs.

*****

Dave Carnell uses multiple layers proportional to ply thickness. My understanding is that his schedule - 3 layers each side for 1/2in ply - is now considered conservative. 

Consider weight of cloth, thread orientation (i.e., orthoganal , bi- or triaxial weaves) and adjacent structure for your particular application.

Have fun!

NOTE: A similar method can be used for wood repair... grind a fair, 12:1 curved dip (or as easy as space allows) across a break and lay in glued layers of wood, bent to the curve. Trim and finish. Works great for frames, but can also be used in place of graving or butt patches.

MUSTELID Venture (Video Series)

MUSTELID
Photo courtesy of David Reece

MUSTELID Venture (Video Series)

Anke and I are proud (and a little nervous) to announce that Small Boats Nation (online, and affiliated with WoodenBoat) is releasing a 15 part video series, produced by ourselves and featuring our MUSTELID Venture.

It is appearing weekends, in weekly installments. 

Episodes are collected in this Playlist and this Collection at SBN as they are released. This is outside their paywall, so no subscription is required to view the series.  

Episode 1 introduces us, how we live, the need and proposal for our vessel.

Episodes 1 - 6 focus on MUSTELID's goals, concepts, construction, outfit, rig and life aboard.

Episodes 7 - 14  follow our trip in MUSTELID around Chichagof Island (plus a detour).

Episode 15 takes a look back on what we learned (I'll link this once released).

NOTE: Releases have been irregular, ranging from one to three week intervals, and Fridays to Sundays. Further, the latestest episodes have been mounted behind their paywall, but these playlists link to open-access Youtube. Go figure.

Plans for MUSTELID and other designs are available at triloboats.com.

*****

Small Boats Nation has a wealth of useful information... please consider subscribing. I've written this article for them about this trip which appears in their July 2023 issue.

Maybury's Laws for the Low Road

From https://www.jennygarrett.global/7-ways-to-earn-and-give-respect-at-work/

You who are on the road 

Must have a code that you can live by...

-- From Teach Your Children Well by Graham Nash

Do all you have agreed to do.
Do not encroach on other persons or their property.

-- Richard J. Maybury's Two Laws

Maybury's Laws for the Low Road

Along any road -- but especially the Low-- a Code is a fine travelling companion.

The further we walk with a Code, the more we internalize its virtues. Cloudy, moral dilemmas condense and wash away leaving pellucid vistas of arid clarity.

Ahem.

A Code cuts through the BS. It blows away the smoke. Guides our choices. Walk far enough with the Code and really, truly we begin to see more clearly, reason more cogently and react more instictively.

But that goes for most any Code. The Samurai had theirs. Fascists have theirs. Predatory capitalists have theirs.

A good Code, by my estimation, helps us ease on down the road. And nothing, me again, nothing  eases our way on any road more than earning and giving Respect. This goes double along the Low Road.

We earn respect through integrity, which in turns makes us reliable. Respect is something it costs us nothing to give, but elevates every relationship it touches. Along the Low Road, we are often assumed to be both disrespectful and unworthy of respect. To ease down this road, we must earn it. To give it freely is to inspire it.

Which brings us to Maybury's Two Laws.

Do all you have agreed to do.
Do not encroach on other persons or their property.

These two laws are about as good a Code as I've come across. The first earns Respect; the second confers it.

Let's look at them in turn.

Do all you have agreed to do...

This is a pretty durn good idea. 

If you don't follow through with what you've agreed to do, your are living down to expectations. Even those who like and love you will not turn to you in their time of need, nor likely be there in yours. You'll be kept at arms distance by most. The next gig will be hard to land. Opportunity will flee.

Let your word be your word. It's that simple.

This doesn't mean you have to agree to anything, much less everything. Be selective about what you agree to... only those things you expect and intend to fulfill. Another's need is not, of itself, an obligation. But, according to this Code, your word is.

Of course, the best intentions don't always work out. But if you cannot fulfill a promise, promptly communicate your inability, your regret and work to make it right. 

Few will begrudge us a good faith effort.

Do not encroach on other persons or their property...

This one's a doozy!

'Encroach'... that's a great word, but what does it mean? I think it's something we each have to answer for ourselves. But we each of us know when it happens to us... turn it around.

'Property'... I've known many's a Low Roader -- and even more High Roaders -- who play free and easy with what constitutes another's property. Our entire culture, having commodified everything, struggles with the notion. The phrase 'the Haves and the Have Nots' gives a glimpse into the the moral mush involved.

Here too, we must find our own meaning. And best do it before that tempting morsel is discovered, unattended before us! The answers we improvise in that moment are likely to be facile.

And that's where a Code helps out. It helps cut our own BS as well as that of others.

What's In It for Me?

These Laws... they're more like guidelines, really.

They're not handed down from God. They're not really enforced across the reach of their jurisdiction. So why follow these and why follow these?

Well... I speculate that the more of us who follow this Code for more of the time, the better the world will be for all of us in it.

I further speculate that, if this Code were a meme released into some evolutionary substrate (human culture, say), it would multiply and come to dominate, outcompeting its rivals.

[You see what I'm doing, here, right?]

Finally, I speculate that we will prosper as individuals if we follow this Code. 

I have followed these Laws for decades, now. It comes natural... maybe that's why I'm drawn to them? Or maybe I'm the result of them? Anke seems to have come that way!

Despite our drifting, dreaming life, we are known to be reliable for that to which we commit. Despite our (technical) poverty, we are known to be trustworthy. Despite sailing full and by without an engine, we are known to be punctual.

And that comes back to us, with interest.

As we travel the Low Road, we follow the Code not because we are good, nor because the Code is righteous...

We're simply selfish.

Dream vs. Reality

Obi-Wan Squareboti

 

A bird may love a fish

    But where will they build a home together?

– Tevye from Fiddler on the Roof

Where are you going?

Who will go with you?

What vessel shall bear you?

Answer these in the wrong order

    And you are in trouble.

– Howard Thurman’s Observation, extended

Dream vs. Reality

Some of the very first advice we got when first moving toward the water was, whatever you do, don’t sleep aboard a boat you’re thinking of buying… you’ll fall in love with it and lose yer objectivity!

And so it was. Sorta.

Here’s the problem, though… the point entire of the whole sordid affair is passion. Practical concerns have their place of course, and maybe even the final say. How do we find the right balance between dreams and reality? 

In Fiddler on the Roof, Tevya is speaking to his daughter who has fallen in love with a young man of another faith and ethnic background. It’s a good question and lovingly posed. Against his wishes, they go forward in love as lovers must. Who knows the outcome, for them or for any of us in the real world? 

We love. We act on love. We live the consequences of our choices.

The western-ish Apollonian imperative - know thyself - is excellent advice, but a little passive for my taste. To it, I would add the eastern-ish, Zen imperative - seek balance.

Day-dreaming a vessel is a wonderful passtime. Not only does it carry us to far and fragrant shores, but fills our hearts with those things we relate to as the well-springs of passion. Sometimes its sheer escapism from our daily grind is a soothing and revitalizing relief.

For we are embedded within a life of our own making. Our priorities and choices have cocooned us within habits, relationships and obligations. I don’t disparage… we’re all entangled, one way and another. But these are more or less the ecography of our lives.

So, if we have made a life we wish to more or less continue - have a home ashore and full of family, perhaps - it constrains our passions for, say, a vessel. Or, maybe better put, it informs our passions.

Just as the parts of a vessel must work together to fulfill its purpose… just as it must be fit to face the waters it sails… just as its accommodations must accommodate its crew… so must it conform to its place within its owners’ life.

Here’s a subtle difference… I propose vs. I purpose. Americans tend to the former, British to the latter. In the case of adding a vessel to one’s lifestyle, I prefer purpose. It’s intentional, rather than hypothetical. Hypotheses have their honored place, but sooner or later, they’d better resolve… options winnowed to purpose followed by action.

And once in action, be persistant! More stubborn than mules!!

For adding a vessel into one’s life is no small affair, whether by one’s own hand or by simple acquisition. The success of the venture hinges on how well dream and reality comport. As in any other endeavor, the better matched our hopes and expectations with our actual wants and needs, the better the prospect of success. 

Wrecks of dreams on the bedrock of realities litter the boatyards and backwaters of the world.

Not enough dream; what’s the point?

Not enough reality: no dream comes true.

So here’s my advice, taken in order…

Know thyself. 

Seek balance. 

Dream as you purpose to live. 

Go fall in love.

Persist.

Realize your dream.

[Note: Thanks to David Reece for the (facetious?) moniker; Obi-Wan Squareboti!]

Duetude: Rowing in Tandem

 

The Owl and the Pussycat sailed to sea
in a beautiful, pea-green boat...

Image from the MirrorOnline

If you want to go fast, go alone. 

If you want to go far, go together.

-- African saying

Duetude: Rowing in Tandem

There are a few things in modern life, undertaken by couples, which require sustained, closely coordinated physical effort. Dancing, and folding large tarps come to mind.

And then there's rowing.

To row a boat together - each with a pair of oars - well... first there are the thousand or so strokes of bickering.

Our cockpit is on the small side, so we can bump if we're a little out of sync. You know. Scratch a nose. Adjust a cushion. Look at the birds.

Both of us are facing aft, and I'm usually at the aft, mid-ship oars (they're longer and I'm bigger). My job is to look over my shoulder as I begin to pull, matching Anke's stroke, and thereafter maintain a steady rhythm. Oh... and if a little bit of oar steering is needed, I favor the correct oar, and maybe even call out RIGHT OAR! or LEFT OAR! in a voice loud enough to hear.

You'd think that's simple enough. It is but it ain't. Takes a while to get each of those down, and a while longer to get 'em in combinations.

Anke, at the forward oars, is continuous power. Her job is to watch out for any quirks in my cadence and avoid collision with my shoulders. She too needs to be steady on the oars, to keep all four moving free. She's got to respond to steering commands promptly, and occasionally shout out some of her own if I've drifted off somewhere.

You'd think that sounds simple enough. It is but it ain't.

But the bickering dies down after a day or two, and the magic sets in...

The magic of moving our vessel... gliding across calm water or working our way into a headwind. The magic of passing through vast and wild land- and seascapes. The magic of our bodies working together in sync, muscles aglow and warm with the effort.

We pull together as one. Our hearts beat as one. We face the work and dangers as one. We savor the pleasures as one, not least those of our own company.

Duetude.

Happy Valentine's!