Boat Design for Low Maintenance

Discussion in 'Boat Design' started by TDG, May 30, 2021.

  1. TDG
    Joined: Oct 2020
    Posts: 7
    Likes: 1, Points: 3
    Location: Annapolis, MD, USA

    TDG Junior Member

    One thing that I have noticed is that in the recreational boating market, there appears to be very little emphasis - at least in marketing - on low maintenance boats. In contrast, in commercial shipping reliability and maintainability is often right up there, and sometimes more important than, purchase price and cargo. Practical Sailor has some good info, but I'm interested in thoughts at a more system level.

    The (admittedly ridiculous) goal is:
    • 12 hr/yr maintenance (corrective and preventive)
    • 1 overhaul (25 hr of inspections, 250 hr DIY labor, 20 hr specialist labor, up to 30 d on the hard) every 10 yr
    • 12-14 m/40-45' liveaboad sailboat (2 heads)
    • All the mod cons (must have auxiliary propulsion, some sort of electrical generation, galley with refrigeration, electric anchor windlass, autopilot; desire watermaker, A/C, heat, hot water, electric winches, wind vane)
    • Salt or fresh water
    • Ideally ability to store on the hard during the off season
    • Assume the more challenging of tropical or temperate environment
    • Quotidian cleaning (including slime from the bottom) is allowed in addition to the annual maintenance requirement
    • Winterizing, if necessary, is allowed in addition to the annual maintenance requirement
    • 1/yr bending on of new white sails is allowed in addition to the annual maintenance requirement
    • Unlimited bending on of new colored sails is allowed in addition to the annual maintenance requirement
    • 12/yr underway sail repair (i.e. tape repair) is allowed in addition to the annual maintenance requirement
    • 1 set of white sails/5 yr
    • 2 sets of colored sails/5 yr
    I'm willing to trade somewhat on these ambitious goals, but I figured I would aim for the moon, so I can at least get to the clouds. For example, I'd probably be okay with two weekends for two people (50 hr/yr) annual maintenance rather than one day for one person. Maybe increase the overhaul duration or frequency as well. However, if we could get to the goals above, that would be ideal.

    I'm looking for your thoughts on how to architect the various systems to enable that, and, if any, particular products. I've divvied the boat into the following bits:
    • General Structure: Hull, bulkheads, etc.
    • Bottom Paint
    • Topside Paint: Paint above the waterline, excluding nonskid.
    • Non-Skid
    • Rigging: Mast and standing rigging, including chain plates spreaders, bowsprit if fitted
    • Sail Handling: Sheets, travelers, and everything to handle them (block and tackle, winches)
    • Auxiliary Propulsion: The motor and drive train
    • Power Generation
    • Electrical Distribution: Breaker boards, wiring, and any power electronics
    • Batteries
    • Interior Lighting
    • External Lighting: Nav lights and deck lighting
    • Navigation Equipment: Instruments and displays
    • External Communications: VHF radio as well as any wifi or cellular/WAN
    • Steering: Rudder, stern post, tiller/wheel, autopilot, wind wane
    • Salt Water: Any sea water systems in the boat includes through-hulls and watermaker
    • Dirty Water/Toilet: From the toilet/shower/sink to the holding tank
    • Fresh Water: From the fresh water tank to the sink/shower/maybe toilet
    • Tanks Fresh and gray/black water tanks
    • Cooking
    • Refrigeration
    • HVAC: Fans, A/C if fitted, heating if fitted
    • Anchoring: Anchor, chain, and windlass
    • Safety Equipment: EPIRB, life raft
    • Tender & Boat Handling: Tender and motor, as well as any davit it might have
    • Interior Outfitting: Furniture and cushions/matresses

    Here are my thoughts, which may go on a bit, so you can skip if you like:
    • General Structure: I think you don't have too much choice but to go composite, right? If you went aluminum, you wouldn't have to worry about topside paint, but I have no experience with aluminum. This should more or less take care of itself both during annual maintenance and the overhaul
    • Bottom Paint: 10 yrs between applications probably pushes you to something like Coppercoat, though I understand that has somewhat of mixed reviews. Maybe ultrasonic antifouling, though that adds its own maintenance requirements. During the overhaul, you would need to recoat.
    • Topside Paint: Based on what I've read, it sounds like you might be able to get 6-8 years out of two-part polyurethane paints. Are there other options like high-solid epoxies that can stand up to the UV? Basically, the goal would be to limit the need for waxing or polishing. Like the bottom paint, this would get redone at the overhaul.
    • Non-Skid: I think this is in the same boat as topside paint unless you went with a peel-and-stick and budgeted to reapply in the fifth year's maintenance window, though that limits your other available maintenance. Peel and stick may make the overhaul quicker, so it may be the way to go, since redoing all the paint will probably take up a decent chunk of the outfitting.
    • Rigging: I imagine you would want to go with UHMWPE (Spectra/Dynema) for all of your running and standing rigging. To the maximum extent possible, you would need to go with solid low-friction rings for redirects. Maybe I'm missing something, but I imagine you still need blocks for the main sheet, main vang, and maybe the cunningham. For chainplates, I would probably want either composite or titanium. The chainplates could probably survive for the life of the boat, but the lines will need to get refreshed
    • Sail Handling: You definitely need one winch for halyards. If you locate that underneath a dodger, you may be able to reduce your maintenance periodicity. Could you get away with just during our overhauls? If you had a small jib/staysail you might be able to get away with a block and tackle over a winch for the sheet to avoid a winch. You may even be able to get away with a pure bollard if you only use your colored sails in light wind...maybe? I think you probably need to assume two headsail winches. I think furling head sail(s) would be desirable, and probably okay under the maintenance budget. Winches and the furler drum would need a rebuild during the overhaul. The blocks might need some replacements or rebuilds.
    • Auxiliary Propulsion: Could you fit a diesel in within the time constraints? I'm thinking it would be hard given everything else, which means electric drive, and the more sealed the better. It's probably too early to figure out the MTBF of those, which means you are going to need access so you can replace it quickly if necessary. Likewise, I'm not really sure what would be required during the overhaul.
    • Power Generation: You probably want solar here, since generator/alternator maintenance is going to be prohibitive. You may be able to get away with just regen from your motor? That would certainly be one less system. If you are going with solar, you would need to figure out how to pot or otherwise waterproof your connectors so they don't need much maintenance. During the overhaul (if not sooner), you would almost definitely need to re-do the connections. You may want to replace the panels, though they can generally go 25 yr.
    • Electrical Distribution: You would generally need to make sure that everything is well waterproofed, and figure out how to limit humidity/corrosion. Could you effectively pot every connection some sort of non-conductive grease so that you can still do maintenance easily? Maybe silicone vacuum grease? At least some elements would likely be corroded by the overhaul, so you would want to budget some time for replacement. To facilitate replacement of wires, you would want conduit.
    • Batteries: Lithium iron phosphate is pretty much a given if you go electrical propulsion. I think the batteries should last at least five years. So far a lot of things are pointing towards at least an extended maintenance window at five years. If not before, they would likely need to replace them at the overhaul.
    • Interior Lighting: LED's should get you at least ten years. You would want IP67 to maximize life. One easy item! The only question would be whether a physical switch or a smart switch is more reliable. I'm guessing a physical switch.
    • External Lighting: Ditto.
    • Navigation Equipment: I think you can typically get about ten years out of most modern nav systems, right? I know that you would be outside the support windows for most makers towards the end of that, but you would probably be okay. The other option would be to go the open source direction, but, honestly, if you include that in your maintenance budget, I'm pretty sure you're hosed. The nav suite would probably need to be replaced during the overhaul, so you need conduit to facilitate running any wires, for example when NMEA 2000 moves to whatever the next standard is.
    • External Communications: Likewise for VHF. You could probably do okay if you got commercial grade wi-fi and WAN as well, as long you weren't too worried about being a generation or two behind towards the end. Otherwise, changing it out probably wouldn't be a big deal. Other than the VHF radio, everything else it pretty easy to turn over, but conduit in the mast would be necessary to replace the antenna cable, if necessary.
    • Steering: I don't think a wheel is that much more work than a tiller, right? Now, the autopilot and/or wind vane might be another thing. I admit this is an area where I'm a bit at sea. Probably need to budget some time to rebuilds during the overhaul if not the annual maintenance.
    • Salt Water: There's a really cool pizeoelectric pump out there that you ought not to need to rebuild, but it maxes out at 7 L/min, which really isn't enough. Are there any non-traditional options that you could go with to reduce pump maintenance? My first thought was eductors, but you still need a pump. Would an air pump be lower maintenance than a traditional water pump and then use a gas-over-liquid eductor? If we end up with pumps, then you need to budget time to rebuild them during the annual maintenance. Likewise for any watermakers.
    • Dirty Water/Toilet: I like the idea of a composting toilet, which means that all your waste water is pure liquid, and anything that will deal with salt water okay should be fine. However, what options are there for a more traditional toilet? I would assume fresh water. Probably need to rebuild the toilet every year or two.
    • Fresh Water: I'm not sure you save much with foot pumps over electric. In this case, 7 L/min is more than sufficient flow, so the solid-state option is fine. Otherwise, pump rebuilds.
    • Tanks: Is it lower maintenance to go with water/waste tanks built into the hull or unitary plastic tanks? Probably need a flush during the annual maintenance. If they are not built in, then good removal paths are necessary so that the tanks can be inspected, and, if necessary, replaced during the overhaul. If tanks are built in, then you need time to recoat during the overhaul.
    • Cooking: If you already have electric propulsion, then electric cooking seems to me to be a no-brainer. Replacement may be needed during the overhaul, so easy-switch out is required.
    • Refrigeration: While it's less efficient is a TEM worth thinking about for reduced maintenance? Compressors probably have maintenance requirements every couple years, though to be honest, I'm more used to ice boxes.
    • HVAC: A/C is non-trivial from a maintenance perspective, as well as power. If heating is necessary, hopefully you could get away with a stove of some kind, or maybe electric while plugged in? Maybe radiant electric heat?
    • Anchoring: You're going to be stuck doing the maintenance on the windlass if you have one, so then it's a question of low-maintenance brands. For chain, I'm thinking galvanized is probably fine, right? The chain would likely need to be regalvanized or replaced no later than the overhaul.
    • Safety Equipment: EPIRB is a replacement item. I think the periodicity on most life rafts is five years. All of these *should* be pretty quick and easy. Need to inspect and/or replace during the overhaul.
    • Tender & Boat Handling: A rigid dinghy will probably require painting, while an inflatable will require periodic repair. You could go with a pure plastic and simply replace, I suppose. For the motor, electric is probably lower maintenance than gas. If supplied, I imagine you would want to use the existing winches for the davits. Davits probably need a rebuild during the overhaul.
    • Other Deck Equipment: Lifelines are probably fine either wire or fiber, and jacklines likewise. All of it would need to be checked during the overhaul.
    • Interior Outfitting: If there is woodwork on the interior, it can probably make it to the overhaul to refinish. Cushions probably need to be inspected, and possibly replaced, at the overhaul.
    I do want to preempt one comment, which is 100% correct, but not the goal: Yes, any system not on board doesn't need to be maintained. That is completely true, but the point of this boat is to have many of the creature comforts, and, if the maintenance can be otherwise reduced sufficiently, to add more comforts.

    Best,
    - TDG
     
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  2. Robert Biegler
    Joined: Jun 2017
    Posts: 40
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    Location: Trondheim

    Robert Biegler Junior Member

    When i read a little about metal boats, I came across copper-nickel alloys, specifically chosen for low maintenance on account of being very corrosion resistant and having low fouling even without paint. The material is expensive, and because it has the same density but a bit less strength than steel, the hull ends up being heavier than an equivalent steel hull, but when time taken for dealing with fouling or painting is expensive, the material sometimes pays in the long run.
     
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  3. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    You are overthinking it.
    Hull: gelcoat with molded in non skid will last the lifetime of the boat, no maintenance required unless desired. LPU paints last 10-25 years. Unpainted Al lasts until galvanic corrosion catches up with it, ferrocement until water gets to the reinforcement. The interior can be anything, even wood ones last a long time.
    Standing rigging is changed on a fixed intervall, determined by your insurance.
    Running rigging and sails are changed depending on use and UV degradation. Sometimes they need washing. Sunbrella usually lasts longer then the thread it's sewed with, unless one uses Tenara. Winches need regular service, but most don't get it and they still function.
    Metalwork is best in titanium or bronze, those are maintenance free, but properly electropolished stainless is not bad. Al lasts as long as you don't give it cause for corrosion.
    Antifouling is a recurring operation, but you don't need to take it all off every time, only once in 10-20 years. If the boat is fast enough or you are willing to scrape regularly, sillicone antifouling works, but can not be stored on the hard or see fresh water. Annodes get changed when used up.
    Diesels need regular service, you can not skip it. It doesn't matter if it's a propulsion engine or generator, you still have to change the oil, impeller, service the cooling, etc. Outboards, same thing different flavor.
    Hypalon dinghies have a really long lifetime, and the hard ones as long as the hull materials themselfs. You still have to wash them and replace wear and tear.
    Anything electric can be waterproofed if you like. Use tinned wire, adhesive lined heat shrink, and mount the distribution panels and electronics in watertight boxes with silica gel packets and waterproof cable penetrations. Marine electronics usually last long enough to be replaced because of owner desire, not corrosion or malfunction.
    The rest of the systems are operation and construction specific. Plastics age whatever you do, so after some years it's time. They are still often the better option in the marine environment, and some things last a lifetime.
     
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  4. clmanges
    Joined: Jul 2008
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    Location: Ohio

    clmanges Senior Member

  5. TDG
    Joined: Oct 2020
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    Location: Annapolis, MD, USA

    TDG Junior Member

    Thanks. That's some great info! So, the biggest system that isn't discussed is the plumbing. Do you have any thoughts there?

    clmanges,
    I guess I've just blown up too many spinnakers. Though I've found a kite to be typically quarter to half the price of a good quality main for the same boat. (That's a finished sail, not the cloth).

    Best,
    - TDG
     
  6. Dejay
    Joined: Mar 2018
    Posts: 720
    Likes: 136, Points: 43
    Location: Europe

    Dejay Senior Newbie

    One reason I dream of building a purely solar powered electric trimaran is reduced maintenance.

    There are very little moving parts except an electric outboarder or pod drive. The rest can be sealed pretty well like still >90% efficient solar panels after 25 years. No rigging or sails that wear out. Solar panels are cheaper than sails!
    So I am hoping that I can invest some money up front and then not have to worry about maintenance. But even something like mppt battery chargers contain capacitors that age and fail.

    So spares / replacement parts and as much DIY or able to repair is I think the best you can do. Whatever hardware you can manufacture with a 3D printer would be good. Even if you don't have one on board you could always find someone who can 3D print a spare from a file.

    And replacement parts for like water maker, chargers and electronic boards. If you can run the navigation on a raspberry pi you can afford to bunker a bunch of replacement boards. Maybe do some other sensor things with arduino for the same reason, although at some point it becomes just too much DIY.

    I have no clue about sailing but I'd be curious if you can trade performance and speed, like with a heavier cloth for more durability. An unstayed mast (e.g. harry proas) also seems like a good way to reduce maintenance and number of deck hardware.
     
  7. clmanges
    Joined: Jul 2008
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    clmanges Senior Member

    Heavier sailcloth doesn't necessarily equate to more durabilty; you also have to consider the stress on the system. TDG up there is blowing out spinnakers, which makes me think he's probably pushing the limits of his standing rigging, and the sail is acting as a circuit breaker. Meanwhile, some very large junk-rigged ships have cruised into port with holes in their sails that you could literally drive a car through, and nobody aboard got stressed over it because sail damage is localized. Oh, Panel 6 is two-thirds gone? It'll still sail, just maybe not quite as fast.

    I'm not a fan of proas, but this guy is running junk sails on his now, and he's engineered a very ingenious solution to re-rigging for the shunt.

     
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  8. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    Tanks: Monel and titanium are forever and have a price to match. HDPE is only for the boats lifetime, but significantly cheaper. Stainless and Al are not worth the cost (you can of course disagree). Fiberglass tanks (separate or integral) need special resins according to destination, but can be home made.
    Plumbing: PEX with plastic connectors, properly supported, last the lifetime of the boat (actually we don't know how long it lasts, you can ask your regular plumber). Choose diameters so that the connectors don't restrict flow.
    Valves (including trough hulls and faucets): plastic, bronze or 316SS. Brass, even plated, should be avoided. What you choose is a matter of what you believe in.
    All things with moving parts experience wear, so all have a limited life. Some things are rebuildable, some not. Things like pumps for example, you can not predict how long they will last, because one could fail from wear, or from simply sitting around and some membrane or seal ages until it is stiff and cracks.
    Some things like refrigeration and HVAC you have no choice, you get what is on the market, install them as instructed (or as best as the situation allows), and then it's hope for the best.
    When plumbing one should use common sense, don't install a pump in such a way that in the event of a leak all the water goes onto the motor, if you use crimped connectors buy the proper tool and install in such a way as to have access, etc.
    Toilets are personal preference, you can look up the types and brands, and what the users say about them.
     
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  9. TDG
    Joined: Oct 2020
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    Location: Annapolis, MD, USA

    TDG Junior Member

    Absolutely, though for a given boat, and a given technology, heavier sail cloth is going to be stronger. The one confounding variable is technology/material. For example, a double-taffeta laminated sail (two thin layers of dacron as a wear surface, two layers of mylar, and a core of some sort of fibre) is way lighter than even a fairly light weight dacron sail let alone honest to goodness canvas, and will probably last longer, at least than light-weight dacron. But double-taffeta is heavier and more durable than single taffetta, is lighter and more durable than an uncoated laminate. Likewise 16 oz dacron over 12 oz dacron, over 8 oz dacron. (But the 8 oz dacron is probably heavier than the double tafetta laminate.) As clmanges points out, a junk rig is generally lower stress than a comparable Bermuda rig.

    That's what happens when you're racing. Trim for max speed (force), and then a gust, and...bam. Time for a sail change.

    Best,
    - TDG
     
  10. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    I'm not a sail guy. But do spend an inordinate amount of time on commercial vessels, lived aboard for many years as well as fish some years as much as 10 months a year. Have spent most winters since early 20s fixing boats living in or near yards, my family fixed boats as well and spent time in and around shipyards since adolescent times.

    Silicon bronze thru hulls appear to have roughly a 40ish year lifespan. Not scientific but it seems that most of the "surprise " my seacock snapped off coincides with roughly 40 years old.

    In really remote waters zincs will make it 2 years. In any modern harbor.... no chance.

    Circumnavigation blogs have been in YouTube long enough it appears saildrives are as reliable as political campaign promises, feathering propellers still need work on what appears to be every other haul out, the only maintenance free is the ever drag inducing straight shaft solid prop.

    In the commercial sector oversizing up to a point seems to help increase certain things last much longer. Usually at the cost of weight and $$$$$. Specifically, transmissions, shafts, winches, and rams. Obviously there is a point of diminishing returns but it certainly seems to help if only observationally/anecdotally.

    I have a 42 foot commercial boat that eats an alternator about every 8 months of operational time. It's done so with a shocking degree of regularity. Just did the 8th alternator. They are 115$ locally and take about 10 minutes to swap. At a trade show a specialty electric guy said he had an option that would last for years. The cost was about 30 years of new alternators.... sometimes repair is easier than preparation....
     
  11. Rumars
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    Rumars Senior Member

    Do you know how and why the alternator fails? Such regularity points to either an installation problem, or operating error. While it's cheap to replace, it would be better if it would not fail in the first place.
     
  12. clmanges
    Joined: Jul 2008
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    clmanges Senior Member

    Well, now I know a little more about sails, but feel like I know less, haha. Thanks for giving me a peek into the depth of the subject; I'd never known about these sophisticated laminations before.
     
  13. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    Its overworked. When the boat was designed the only 12v was a bilge pump running lights and a couple cabin lights. Fast forward 40 years and everything is 12v. The pulley ratio keeps it at peak performance at it's most common used rpm. Upsizing to a larger body alternator would require extensive modifications to fit. Not optimum but it has only left us stranded once for about 30 minutes.


    I used this as en example because sometimes we need to realize boats are so much a series of tradeoffs. Having watched a lot of circumnavigation video blogs a pattern emerges. About every other year they are fiddling with the shafts and props on the feathering props. Some from normal wear some from some kind of strike, but all end up being fixed or pulled apart if the blog stretches into more than a year. I've run straight shafts with fixed props in commercial boats that went decades with little more than a zinc change. But most would gladly carry some spares and deal with feathering prop repairs than drag a fixed blade.

    A super bomber double layer sail might last forever but sail poorly in light winds and be miserable to handle in daily life. Would it not be better to have a simple high speed low drag spare?
     
  14. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    That's certainly not a problem requiring 30 years worth of new alternators to solve. Go to your local auto electrician and ask him to convert the standard alternator to external rectification. If you have a metal hull or a pipe carrying cold seawater, you strap the diode block to it, if not, use a big finned radiator and a computer fan and move it outside of the engine room.
    If it's not to much trouble you can add a duct bringing cold outside air directly to the alternator body.
     

  15. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    Was looking at some log books that my insurance company wanted to see. One of my predecessor's took immaculate records and I've continued the trend.

    Things that come to light.

    LEDs appear to fail, while longer lived than monofilaments take out the entire housing. I've lost vision x as well as rigid at roughly the same rate as chineseium. Bulbs were cheaper.

    My water pump on one boat is 7 years old 9 on the other. Yet no toilet motor has lasted more than 18 months with the average rarely making it a year. Manual pumps were less reliable, even the expensive one.

    My oil analysis shows the isuzu can go 500+ hrs between oil changes, the john Deere based ones not so much.

    Traditional packing is more maintenance spread out, but I've never had one catastrophically fail. Have had a drip less go.... it was an expensive fix and a scary week.

    Lots of odd things in the reliability standpoint. Maybe a composting, it stands out as a constant source of breakdown.
     
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