Trimaran - Especially Searunner - Owners

[owly]

Originally Posted by Redreuben

Supplementary question.
Owly, are you suggesting making ice separately from the main cooler ? Like in a superinsulated box ?
And then transferring it to a cooler.
I would think that running a freezer is a lot of resources but purely making ice is good energy storage.

exactly! Running a freezer IS a lot of resources as you say...... but the whole idea is that you do it when those resources are available. Those energy resources are "surplus" at that time, and would otherwise be going into a battery, and later drained out of that battery for refrigeration when a mindless thermostat says "go". Batteries are at best about 85% efficient, and at about 7 times the weight per watt hour of energy stored, it makes sense to make ice for refrigeration, rather than running a refrigerator. Swapping out ice packs is a another manual chore that could consume 5 minutes of your precious time. Otherwise iceboxes are completely passive and very reliable. As batteries are heavy, and have a short life, and are expensive, this makes perfect sense to me. Normally any compressor driven refrigeration system can make ice, so if you plan on refrigeration anyway, why not? A good ice box not constantly opened, can maintain temps for days. A refrigerator has zero energy banked, for all intents and purposes, and must be fed with a constant power source, or it will quickly lose it's chill. It's exactly the same thermodynamic principle used for passive solar heating, but in reverse, and a bit more complex. I know of a unique homestead......... pretty much gone now, though largely intact when I was younger, where they used "passive refrigeration" sort of. The house had an insulated cellar beneath the kitchen, using grass, wool, etc, the things that were available at the time. An array of troughs were out front, and could be filled from the windmill pumped well, which was also used to fill the cistern that supplied the kitchen via a sink mounted "pitcher pump". In freezing weather........ and we get a lot of it here, the troughs were filled, and the ice dumped out, and slid into the cellar via a chute, and buried in sawdust........ "Typical Ice House" you might say, but it was NOT typical at all. In the kitchen was a "dumb waiter", a sort of manual elevator, which lowered milk, eggs, etc, down into the ice house/cellar. There was also provision for storing things on shelves, as the cellar could be accessed via a stairway, and hooks for hanging carcasses. The cellar actually took far more space than was under the kitchen. I wandered through the collapsing remains of this house almost 40 years ago, and it's many innovations drew me back again and again. It's part of a large ranch of close to 50K acres that belongs to friends of mine...... I've known and been friends with 4 generations of them. It was quite a few years before I put the picture I described to you together.... The rotting remains of the troughs, the windmill, the cellar full of sawdust, the strange chute from outside. I'd seen enough of Mr. Mitchell's genius, the long gone homestead family, that I was always looking for innovative things. I don't know of anybody else who put the puzzle together. Few people I have met knew the family, and those few are also long dead. They remembered him as a bit "harebrained" and extremely innovative, but weren't curious enough when the property sold through a number of owners, to put the picture together. His cattle guard was the most outrageous of his innovations........ Two concrete ramps that took his car up and over the fence and back down. They also served as fence braces and still do. About a foot wide, and spaced for a Model T, I've only had the nerve to cross it once!! I had a vehicle with the same (more or less) track width. H.W.

[Cavalier MK2]

It is a good idea, I already have the ice box.

[Buzzman]

While this might seem on the surface to be a good thing to do, from a phase change/energy expediture point of view it isn't, and for a multihuller, not a great option either.

Alas, I don't have the math (or physics) to explain it in better detail, but essentially what HW says is correct, ice is a good way to store energy "that would otherwise be wasted".

Note the emphasis. Only if the energy would otherwise be wasted.

And I concur that a "standard normally insulated refrigerator" is a pretty inefficient heat pump, and they do tend to require a 'constant stream of electricity' to keep the compressor operating and keep the temps constant...

...however....

"IF" the fridge is a more typical 'boat fridge' - ie: built in, with THICK insulation of at least 100mm (4") on ALL sides, this is NOT a "typical refrigerator" and is in fact a 'super-efficient' fridge.

Note the qualifications - the insulation MUST be thick and MUST be on all sides, bottom AND the top (this is often ignored or minimal due to difficulty of access).

A further qualification would be that "IF" the batteries themselves are efficient (which, substantively, lead-acid batteries are NOT) then storing energy in the battery is, indeed, marginal.

BUT, if the battery is a more efficient type, such as gel or, even better, lithium chemistry, and best of all, Lithium Ferrous Phosphate [LiFePO4], then storing "waste" energy in a battery is far more efficient than converting water to ice.

A "properly insulated" 12-VDC fridge should use significantly less power than a less-well-insulated RV fridge, or 'typical commercial boat-builder's idea of a fridge'.

But, to back up HW's idea, it is well-known in RV circles that keeping bottles of water frozen in the freezer compartment of the fridge, and rotating them in and out of the fridge compartement, leads to a lower energy draw even with the crap insulation in RV fridges (on which most 12-VDC 'boat-fridges' are based).

This is in fact the principal on which 'eutectic refrigeration' is based, in which a salty solution, which freezes at a lower temp than fresh, potable water, is used as part of the insulation on a fridge compartment. Freezer bricks utilise the same idea.

Ask me how I know this crap?

I used to write for an RV magazine and several years ago did properly documented and observed 'heat-stress testing' of the various brands of portable RV fridges - and we also did some 'myth-busting' of the popular myths, such as the keeping milk bottles full of frozen water in the fridge.

Lo and behold, we actually could prove that this worked....but....

Adding an extra layer of insulation to the fridge compartment was a FAR better predictor of low current draw. The more insulation, the less amps drawn. By a significant margin, adding insulation was the most efficient predictor of lower current draw.

And this was regardless of the temperature gradient (we had thermocouples inside and outside the boxes, in a "thermostatically controlled environment" at a Defence testing facility, in which we could program a heat ramp, up and down, to simulate normal diurnal temp variation under controlled conditions).

So, the bottom line is, if you have "free energy" from the sun and can convert it into frozen water, and store this frozen water in a sufficiently insulated cooler box, it works just as well as a 12-VDC fridge that is EQUALLY well-insulated.

The principle advantage of storing the 'free energy' in a battery (and the downfall for boaters of the 'frozen water storage concept') is that 'energy' can be used for things other than running the fridge compressor - like lights, music, computing, navigating, etc. Ice is just ice. Unless you're really into daiquiris....

BUT, as you need a freezer, anyway, in which to freeze your water into ice.....as well as something in which to store the ice and keep your food cold, that requires an ADDITIONAL storage compartment that takes up much needed boat real estate.

Final word: The reason ice boxes and ice-cooled cellars were so popular in the 18th-19th Century was because the ice was hauled from frozen lakes in the north in huge chunks which, due to their mass, didn't melt as quickly as the tiny cubes most ice-makers produce today. So it was 'cheap' - though not free.

Once ammonia-based 'absorption refrigeration' was perfected in the mid-19th century, people found it was easier to burn coal, wood or oil to provide the heat necessary for the phase change of the ammonia, as this was easier than hauling large chunks of ice hundred of miles. So if you already had a steam engine doing something else, the 'waste heat' from the steam engine could be used to run a freezer, making this an "efficient" way of producing ice closer to home.

However, ammonia-based absorption is a relatively inefficient way to operate a heat pump, which is why the compressor-type refrigeration systems, which use the same basic methodology (phase change) to remove heat from the cabinet, but use far more effective phase-change materials/gases, have come to dominate.

There was a big push back into absorption technology with the rise of RVs in the Fifties, but today advances in small 12-VDC compressors such as those from Danfoss has made these older types of fridges reduntant.

Compressor fridges use pressure to change the phases from gas to liquid, then the liquid absorbs the heat from inside the cabinet and changes back to a gas, to be compressed yet again and so on...

Having said THAT, however, from a maintenance perspective, 'absorption-type ammonia-based' fridges have no moving parts. The only thing that can possibly wear out is the burner used to heat the ammonia to cause it to turn to gas which, rising up through the fridge, pulls heat out of the interior, which converts the gas to liquid, which runs back down into the tank above the heat source, to begin the whole process again.

So you "could" use propane as the fuel (or even diesel at a pinch) on a boat, but these days, with "free energy" from the sun and/or wind being way cheaper and more readily available than either propane or diesel, compressor-type fridges are cheaper to run and (almost) as low maintenance as the older RV-type propane/ammonia fridges.

Buy good quality solar panels, stretch the budget to lithium batteries, add THICK insulation, and enjoy the benefits of refrigeration on board.

From a boater's perspective, lithium batteries have the principle advantages of being able to be run down to almost zero capacity for way more 'cycles' than lead acid, and are a tenth of the weight of lead-acid and, needless to say, are lighter than chunks of frozen water. Or at least, not much heavier....

Lead acid batteries, for longest possible life expectancy, need to be cycled through no more than 10% of their capacity. So a 'rated at' 600amp hour battery is, effectively, a 60amp hour battery.

So to get an "actual usable" 600amp hours, you'd need 6000amp hours, or 10 times the number of heavy, lead acid batteries.

Or you could buy one 600amp hour lithium battery. Tenth of the weight, but four times the price per unit of so-called '600amp hour' lead acid batteries.

And from a multihull, and especially Searunner perspective, adding lightness is the way to go.

Thick insulation, efficent modern 12-VDC compressor fridge/freezer, lithium batteries to store energy from sun/wind.....and you only need produce enough ice for the daily sundowner.

Apologies for the essay length post....

[Cavalier MK2]

Interesting Buzzman.... both sides have investment and complexity. My icebox is well insulated..... and I don't mind warm beer on occasion. By the time I get around to changing anything the technology should be even more refined. Which means I probably won't change then either! Having a wing deck tri though means there is elbow room because of the elbows/wings so there is room for light approaches. This lets me have a large chart table, galley separate from traffic, wing bunks that keep the settee and table free for use etc.... Things that use space but don't add much weight if they are part of the structural envelope.
In any case evaluating these things should be done carefully, there isn't a benefit to skipping the math for sure.

[Buzzman]

Precisely my point.

If you already have a substantial, built-in icebox, then a small freezer to enable you to freeze large bottles of water (eg: 2L milk bottles or other rectangular section bottles - important as it doesn't then allow air to circulate in the gaps between cylindrical bottles), might be a good, and relatively simply addition to your cruising kit.

For someone rebuilding or refitting, it makes more sense to add insulation at that point in time - not less than 4" for preference, even if it means having a substantially smaller internal fridge compartment - as the energy savings, and the resultant savings in battery storage and generation capacity more than make up for this.

Several of the more mainstream 12-VDC RV fridge suppliers, such as Dometic, Waeco, Vitrifrigo, also have in their catalogues a 'build it yourself' kit option, often not featuring on their main websites - harumph - which can be purchased often in variable condensor arrangements to suit available compartments in your boat.

You simply build the box and then add the insulation, drop in the condensor, fit the motor unit (often this can be extended to another compartment remote from the actual fridge/freezer box) which helps with heat dissipation.

There's other things to think about as well - like having a freezer with a 'spillover' design, so that cold air spills from the freezer compartment into an adjacent fridge compartment.

This is one way to have ice, but prevent tomatoes and milk freezing if in the same compartment. Freezer at one end, lettuce on top at the other end.

But always a top-entry compartment. Anything that resembles a domestic front-opening fridge is a waste of space and simply consumes far too much energy.

Back in the day, with only propane RV fridges or 110VAC (or 230VAC) domestic type compressor fridges available, most sailors did as the ancient mariners did - went without.

Many sailors still choose to do so today, and there are a myriad forums on 'non refrigerated stores' for sailboats.

But given the amount of electrickery required these days for safety and navigation purposes - never mind phones, laptops, wifi systems, stereos, TVs and so on, it almost makes sense to have a fridge as well. Especially given the recent drop in cost of solar panels and associated componentry.

Let me put it in another light - if SWMBO requires a flushing toilet before she'll go camping, then it stands to reason she'll also require a fridge before she'll go sailing. So anything that helps "encourage" the better half out on the water.....just sayin'....

It's not "just" about keeping the beer cold.....

Well.......

[Jimske]

Ice, referigeration, AC ?? Demands today a lot different than when Jim designed the Searunner. No wonder many opt for that cruising condo!

In case some don't have this:

The following from Jim's book SEARUNNER TRIMARANS. Table shows displacement loaded for cruising. 30 days water for a crew of 4 going to take up a lot of that 15% increase tolerable. Best to lean toward minimalist cruising?

"Displacement, loaded for cruising, This figure is the total weight of the craft as it is outward bound for a distance crossing or an ocean race in which heavy weather may be encountered, or speed is important. For short cruises when the weather can be safely forecast, and when the boat can be sailed with the reserve not indicated by racing, an increase of about 15% may be tolerated in the total displacement, which increases the cruising payload margin equally. This margin is the amount of stores, fuel, water, people, baggage and general plunder that may be added to the boat when cruising or ocean-racing; added after the boat is already carrying the normal payload of standard tankage, cruising crew, and weekend stores. the "weekend" displacement is not the dry weight, but the usual weight of the craft at the dockside except when ready for crossing or a long race."

[Cavalier MK2]

Actually Buzzman things like the icebox are a great filter for cruising off the beaten track. For adventure sailing you want a bit of a Tomboy for the better half, many gals have done enough camping so it isn't a shock, they like the size anyway. "It's like car camping except we have a self propelled waterfront cabin so don't need to set up a tent."

When I set up the galley I was reading Lin Pardey's "The Care and Feeding of the Offshore Crew" for ideas, since they sailed with a icebox it was a good fit.

Now if I was living aboard full time I might want to do something different. What I need are systems that can sit idle for stretches then go sailing for 2-6 weeks at a time. Sounds like a ice box! In truth I work hard to keep electric systems off the boat. Hand help electronic devices can have their batteries charged off an inverter and be replaced or used elsewhere like the car easily. I'm afraid I still use paper charts too. After helping a neighbor go through miles of wiring this winter so he could leave the dock I felt no desire to change my rustic ways.

My check list for changes.

Weight
energy
cost
durability
size

and since getting the Buzzman's valid feedback
Sex Appeal!

[Seabeau]

Originally Posted by Cavalier MK2

Actually Buzzman things like the icebox are a great filter for cruising off the beaten track. For adventure sailing you want a bit of a Tomboy for the better half, many gals have done enough camping so it isn't a shock, they like the size anyway. "It's like car camping except we have a self propelled waterfront cabin so don't need to set up a tent."

When I set up the galley I was reading Lin Pardey's "The Care and Feeding of the Offshore Crew" for ideas, since they sailed with a icebox it was a good fit.

Now if I was living aboard full time I might want to do something different. What I need are systems that can sit idle for stretches then go sailing for 2-6 weeks at a time. Sounds like a ice box! In truth I work hard to keep electric systems off the boat. Hand help electronic devices can have their batteries charged off an inverter and be replaced or used elsewhere like the car easily. I'm afraid I still use paper charts too. After helping a neighbor go through miles of wiring this winter so he could leave the dock I felt no desire to change my rustic ways.

My check list for changes.

Weight
energy
cost
durability
size

and since getting the Buzzman's valid feedback
Sex Appeal!

I agree wholeheartedly!!

[owly]

Originally Posted by Cavalier MK2

Actually Buzzman things like the icebox are a great filter for cruising off the beaten track. For adventure sailing you want a bit of a Tomboy for the better half, many gals have done enough camping so it isn't a shock, they like the size anyway. "It's like car camping except we have a self propelled waterfront cabin so don't need to set up a tent."

When I set up the galley I was reading Lin Pardey's "The Care and Feeding of the Offshore Crew" for ideas, since they sailed with a icebox it was a good fit.

Now if I was living aboard full time I might want to do something different. What I need are systems that can sit idle for stretches then go sailing for 2-6 weeks at a time. Sounds like a ice box! In truth I work hard to keep electric systems off the boat. Hand help electronic devices can have their batteries charged off an inverter and be replaced or used elsewhere like the car easily. I'm afraid I still use paper charts too. After helping a neighbor go through miles of wiring this winter so he could leave the dock I felt no desire to change my rustic ways.

My check list for changes.

Weight
energy
cost
durability
size

and since getting the Buzzman's valid feedback
Sex Appeal!

My situation is different, as I intend to retire onto the boat and spend years cruising and voyaging in various parts of the world. While I don't need or want all the comforts of home, that would be completely unrealistic anyway, there are some things I would rather not forgo, and refrigeration is one of them. You won't see a microwave, and electric kitchen appliances, or even more than one or two burners on my stove and no oven. You won't see a water heater, or pressure pumped water, perhaps not even foot pumped water. I plan to equip with a composting toilet, and use a solar shower.... probably in the cockpit. My resources are limited, so I expect to anchor out mostly, which I prefer anyway, as I'm a bit of a loner...... Marinas and mooring fields remind me of trailer parks!! I'm not interested in "making the rounds" day after day, visiting other boats constantly, partying, and eating out. Being the only boat in a quiet bay somewhere, exploring a rocky beach or point alone or with a friend.... snorkeling, etc. You likely won't ever see me at one of those big cruiser's beach parties with barbecue and pot luck. Water weight is a significant factor in cruising, at 8.4 pounds per gallon, and half a gallon per person per day. A 3 week passage with two people, and a week's safety margin would amount to 235 pounds. With a simple pedal power water maker, I'd be inclined to budget only 15 gallons (126 pounds) of water. That's a 15 day range with no recharge. That means that if something goes wrong with the system, you have 15 days..... without rationing, to get to a water source. Considering topping up every day with the watermaker, and capturing rain, it would be extremely unlikely that you would ever run short. The actual weight of a watermaker designed to be pumped from your folding bicycle would be fairly small, probably half or less, of the water it replaced, and the real benefit would be never needing to fill up with local water, and worry about it's quality or endure the chemicals. I have drank my own well water, innocent of any filtration or chemicals for over 30 years. High quality from an aquifer fed directly from the nearby mountains, it doesn't even lime a coffee pot. Drinking city water laced with chlorine and floride, picked up out of a river with the sewage from cities upstream, would quickly turn me into an alcoholic!! Cervesa rapido!! H.W.

[Buzzman]

The point about ice boxes is that it's no longer as easy as it was back in the day to find 'block' ice dockside, or even nearby.
These days commercial icemakers produce 'extruded' ice which forms small blobs or 'cubes', which are then bagged in small 2-5kg bags. The greater surface area on this type of ice causes it to melt rapidly, within a day usually, (unless you have a super-insulated icebox), so ice is no longer an especially viable 'cruising' option unless you can get to an ice source every couple of days. Block ice can last days longer.
So while ice is viable for coastal cruising, it's not much of an option for ocean cruising - unless you have an onboard freezer, and in which case, why not a fridge also? Or instead?
Portable RV chest fridges are often seen on coastal cruising boats these days, even on ocean cruisers, but seldom do you see them properly insulated.
Having said that, for the minimal cost incurred, simply disassemble the chest fridge and use its compresor, condensor and internal parts, and simply throw the rest away, or use it as a 'box' to store something else.
So-called dedicated 'boat fridges' tend to be highly specialised and fitted by wounded bulls who know how to charge. But to be fair their costs reflect the labour involved, which a good DIY person can supply themselves.
My point being, it's relatively simple these days to fit viable 12-VDC refrigeration even to a smaller cruising boat, like a 31' Searunner.
'Back in the day' this was not so much the case.
I totally get the minimalist idea of less is more, especially in terms of complicated systems like refrigeration, or A/C....
But my point about the light weight of lithium batteries was intended to indicate that the additional energy storage to run a fridge is now possible without the weight penalty (and effect on cruising displacement) of the larger number of much heavier lead acid batteries that would have been required previously.
Which would you prefer? A 2kg battery or a 20kg battery?
Think about what a case of beer weighs....24 X 375ml = (approx) 9kg.
So taking lithium batteries instead of lead aboard enables you to carry two cases of beer without a weight penalty.
What's not to like?

[Cavalier MK2]

I'm sticking with the ice box. We still have block ice and no batteries = even more beer! We can always chill in the waters up here.

Buzzman, you and Owly need to get boats so you spend less time thinking about this stuff.

[Buzzman]

LOL....

My 24' tri is 'in build' as we procrastinators declare.

So very much still in the 'planning process'. Hulls built but not yet 'glassed. Long ways to go.

I sail dinghies the rest of the time, so don't need a fridge, and the 6-pack Esky/Chilly bin/Cooler is fine for that. Although I tend to use cooler 'bricks' when day sailing, but do use the readily available 'party ice' when on the road, and in our warmish climate Down Under, party ice barely lasts a day, even inside an insulated bag in an air-conditioned vehicle.

It's mid-winter here atm and 'only' 18 deg C. Got down to 6 overnight.
Nah, doesn't get cold enough here to keep ice frozen....

I've even got an insulated soft pack version small enough to take a six-pack (or a cuppla bottles of water...ahem...) with a velcro'd flap in the top so I can access the contents without unzipping the bag proper. Makes it super easy to fish for a drink while under way, and get it back into the cooler bag one-handed.

Trivia quiz question: Why is it called velcro....???

Abbreviation of : VELour CROchet, which pretty accurately describes the surfaces of the two pads.

I'm full of little snippets like that.

Well....full of something, anyways.....

[Redreuben]

Cav; I need a boat too ! But meanwhile I'm learning from others mistakes and thinking is free.
Now since we are talking energy, water and technology density, I have questions. [emoji2]
Short handed or solo an auto helm seems to be a "must have" is it ? I don't rate wind vane steering at all. And what is its energy consumption and Lithium battery requirement ?
Water making also appears to be a must have to save the weight and volume of water storage on a multi so we have three big energy users.
Choosing priorities I don't have the cruising experience to rate them, as it stands I struggle between 1 and 2 but would say 1)autohelm 2)watermaker 3)refrigeration.
To power them I see mostly solar as I'm in Australasia, maybe a small wind turbine and as backup the bicycle gen or alternator on motor.
I'm not that keen on a motor as my future boat will likely be 30' or less, but even a four cycle outboard will have some charging capacity.
I am very much in the camp cruising rather than the luxury camp.
Comments please.

[Cavalier MK2]

In short Buzzman, you are a icebox guy!!! There is hope yet....

Red, I agree with your priorities but I haven't written off vanes. In truth when I sail solo which is often these days I'm a hands on guy but the Nicol can do alright with the helm lashed for a short spell. In fact to windward it can darn near sail itself which has made me lazy but I'd put self steering on top which can be handled on the auto pilot end by solar cells and batteries.
Water making to me is a luxury but a sensible one. I think you should contemplate a boat big enough to haul what you need for a whole lot of benefits.
1 It will be a better sea boat
2 you can avoid expensive options
3 Room is the ultimate luxury.

How to afford it? Embrace your cultural history and keep an older boat going. Every now and then I look at ads and think, "Crikey, I could get that Nicol and spend these lousy PNW winters in OZ." Think about it, this could work for both of us, winters there are summers here.....

I like the pedal options for lots of things and will never get beyond outboards but have spent years at times sailing boats without motors. It is like chess and you visit places you'd never otherwise encounter.

My suggestion is to just get floating and let the rest evolve. Currently I'm upgrading things during our good weather so I can goof of in our next 8 months of rain. Now that is planning.

[Cavalier MK2]

On the battery question. Most of the time it is just one heavy duty regular battery that will also fit in my car just in case. For a long cruise I'll put in a 2nd. This is used when the outboard is running with an inverter to charge things like the laptops and cells and every few days, the battery powered amp for my electric violin and a acoustic electric guitar. The actual wiring is just to the running lights, starter, $10 radio and inverter.