The Offshore Voyaging Reference Site

Boat Maintenance—What’s Your Screwup Tolerance?

We write a lot about gear and boat maintenance issues here at AAC. And then we debate the subject of these technical posts in the comments as we collectively try to zero in on the right way to equip our boats—a valuable process that I always learn from, and one of the best parts of AAC.

But it just struck me that trying to determine the right way, or the right piece of gear, is not a complete exercise until each of us has answered a fundamental question:

What’s your screwup tolerance?

(I wanted to use another word in place of “screw”, but the-editor-who-must-be-obeyed wouldn’t let me.)

Login to continue reading (scroll down)

Inline Feedbacks
View all comments
Marc Dacey

Hmm, my ears are suspiciously warm…

John, you’ve nailed it in the sense that increased complexity means increased aptitude *may* be needed to deal with breakdowns and if one doesn’t actually enjoy boat repair in exotic locales, it could harsh the mellow of the years of effort that it takes for most non-lottery winners to cast off the lines in the first place.

Can’t argue with that. I also can’t argue with affecting the “mission critical” status of the engine. One recalls Parlier’s use during a Five Oceans race in the ’90s of a long line and a crash gybe to get his diesel to crank…and now compression levers are largely past. But I am unclear whether you mean in your list of “no” that these additions risk damaging the engine, OR risk leaving you without cold food or wet feet should, for instance, the engine-run compressor or main pump fail. If one’s fridge kacks, it’s inconvenient, but proper provisioning never relies on the fridge. It’s the fridge that shouldn’t be mission-critical, which is why I wouldn’t have one powered by the engine. And the decision to get a feathering prop ruled out shaft generation, and so on.

Clearly, we differ on the idea of a second alternator. Many cruisers want to get maximum pop from their engine run periods to fully charge up or to make water or run the inverter, etc. To use our own example, many boats with new 60 HP diesels might have one 150-200 amp max. output alternator to charge a “non-coastal” sized bank. If I have two 90 amp alternators on purpose-built power take-offs, I have equalized the belt pulls on the crankshaft, and I have the ability to still have one of the two alternators at work should one require service. I save on wire gauges, but I need to buy two external regulators. To me, it seems “belt and suspenders” thinking, with the added charm that it is easier and cheaper to source a 90 amp alternator (a common size for vehicles) than a Balmar ThunderStrike 9000, or whatever “marine” brand promises amps to weld by. I should say that “alternators” are third in our list of four sources of onboard charging, ahead of “Hondas lashed on deck” and behind solar and wind.

Sometimes, and I freely admit this can be just a matter of taste, keeping things simple can involve some complexity. It’s always akin to dancing on a see-saw in my mind. Sometimes it has taken me years to abandon a long-cherished plan and admit “Really, I don’t need to do Scheme X in such an involved method for such little convenience.” So we aren’t too far apart.

Marc Dacey

Well, I suppose I could have a big alt as the main and a small alt as the spare, in a sealed box in a locker!

I do like the tensioner idea, and my belts are already serpentine.

Thanks, John.

Marc Dacey

So noted, John, and thank you. Because I am set up for two alternators already, retiring the stock one to the spares chest and going for a large case model with external regulation (which was always my intention) shouldn’t be a big deal.

Eric Klem

Hi John,

This is an interesting way to look at it. I guess that my screw up tolerance is probably a bit higher than yours but I do my best to limit any breakdowns during the season. Sailing is by far the most relaxing thing that I do and I really don’t like working on the boat when I could be sailing it. However, I don’t mind doing something like an engine rebuild, for that matter we pulled our engine last weekend and I am partially rebuilding it and should have it back in this weekend. I really don’t want to be doing it (just ask my wife, I have complained plenty about it) but I also can’t stand the thought of not doing it.

This way of thinking is somewhat parallel to what I call people’s risk tolerance. Discussions like what boats are bluewater capable are ridiculous in my opinion because most remotely capable boats will have some knowledgeable person who is willing to sail long distances on it. That person might be a super seaman and/or have a very high tolerance for risk. Another place that this shows up often is in anchor debates where some people set up their gear so that they will have a 99% chance of surviving a cat x hurricane while others figure they should be fine with the manufacturers recommended size because 64 knots is really not that much more than 50. Maybe it is just the optimists and the pessimists. As an engineer, most of my analyses fall into the pessimistic category.

I really like your closing point that there is no single right way.


Marc Dacey

Eric, this jumped out at me: “I really don’t want to be doing it (just ask my wife, I have complained plenty about it) but I also can’t stand the thought of not doing it.” How true this is.

I am in the process of spring commissioning for two boats. This involves a lot of hose clamp tightening, bolt tightening, lubrication/painting, inspection (sometimes involving dental mirrors and strong lights and reading glasses) and replacement or repair as needed. I don’t mind this as the process (16 years and counting) of spring commissioning makes me happy and relaxed. So does the post-launch MOB practice with my family: chuck some floating object in the water and then time how quickly various crew can retrieve it under sail. RYA course-takers will know what I mean.

Stuff that goes wrong on the boats are rarely the things I’ve checked, and I have rarely lost much time or sleep about that inevitability. My tolerance for screw-ups is proportionate to the time I invest at the front end, so to speak. So if something went wrong that I knew it was in my power to have checked and remedied prior to the screw-up, *that* would cause me to become anxious. I have woken up in the middle of the night, got on my bike in the rain and gone down to the boat just to dog down a slightly ajar deck hatch because on some level I recalled that I didn’t secure it properly.

Such is the sailor’s mind…I have no doubt I have company here.

Dick Stevenson

Dear John,
Another thoughtful analysis about the ways we go about making choices in our cruising life. I also agree with Eric that one’s tolerance for screw-ups is related to a tolerance for risks.
I pay a lot of attention to language and its impact, both literal and suggestive. There is some degree of discomfort on my part when I read: “There is no Right Way” when written by a “guru, rabbi, mentor”, (fill in this space) for people working to figure out their patterns and strategies for cruising (or most anything for that matter). Language is a tricky thing and contributes to our attitudes on many levels. When read literally, it is not only in-accurate (there is a right way that people need to figure out for themselves), but more importantly, the statement is suggestive of seductive attitudes along the lines of “Whatever (said with an adolescent drawl)” or “It does not matter”, attitudes far from your intent. I would much prefer a paragraph title along the lines of “Find Your Personal Right Way”: certainly a more awkward statement (more like a yucky self help book), but more in line the subsequent paragraph’s content.
What is meant in part (my take) is that there are a range of acceptable alternatives (right ways) to many of the cruising choices we make, and that, after due diligence at considering this range of alternatives, we pick the one that fits our style best. (I would add that there a range of wrong ways also for most of our cruising choices.) Your subsequent elaboration that there is NO one right way certainly addresses this as does your emphasis that an individual’s right way is found after “thinking long and hard”.
My best, Dick Stevenson, Alchemy

Dick Stevenson

Hi John,
The relationship between risk taking (a going for it attitude) and a conservative approach (slow, careful and methodical) has long been of interest to me. It has been my observation over the years that one’s capacity/tolerance for going into new territory (a time honored form of risk taking) is many times directly related to a formal conservative approach which attempts to minimize screw ups. (Best exemplified by the moon landing.)
Much publicity and acclaim seems to accrue to those individuals who just wing it (or appear to) and it is certainly my take that certain characters can repeatedly just pull off with aplomb what looks impossibly foolhardy to more “sensible” folk. That said, I believe the vast majority of us counter-balance our risk taking with careful preparation. And are wise to do so.
Dick Stevenson, Alchemy

Steven Schapera

My tolerance for screw-ups varies: Engine problems whilst tied up in the marina and getting ready to go out are quite different from engine problems in a howling gale with the anchor dragging and getting blown towards a rocky shore. As John has stated, mission critical systems dictate a different approach. “Aim for the impossible to achieve the best possible” comes to mind. I aim for an absolutely reliable engine, so don’t take risks with it. Nothing destroys a wonderful holiday more than waiting in some port for a week or more for a part to arrive….


On the subject of hanging extras or even more powerful alternators off the crankshaft pulley, I think it should not be done unless….
The engine does not use the alternator pulley to drive the cooling pumps and that the manufacturer specifically allows the extra side loads.
My perkins sabre 135 has internally driven pumps. The standard 3 groove pulley can be used for what you want.
The engine, once started requires no electricity to keep running, which I also think is an added safety benefit. It does require 12v into the pump to stop it ,but not to keep it running.


My screw-up tolerance varies dramatically according to where I am and who’s with me.

If we’re up in northern Ontario for the July long weekend, no one is too worried about taking the old aluminum skiff and its ’79 OMC engine out for a spin, even though that motor has about a 1 in 20 chance of acting up on any given trip. There will always be a friend’s / neighbour’s boat within view, or within rowing range, in a few minutes.

Taking that same boat out on the Thanksgiving long weekend is a completely different story. With the entire river system nearly deserted, the motor’s unreliability becomes a significant danger, and the boat is shunted aside “for emergency use only”.

Offshore work is much closer to the latter scenario. Even if the probability of gear failure were the same (it’s not), the risk calculation has to take into account the difficulty and low probability of easily obtaining a tow, a mechanic, spare parts, etc.

(By the way, if you’re wondering “why would they keep unreliable engines around?” – our ’79 OMC and a couple others on the lake are being replaced this year, but it takes many years and many tens of thousands of dollars to bring the whole lake fleet up to modern standards. There’s an unwritten agreement to always go out and tow each other back when something breaks.)


A very good article because it shows that everything one reads must be critically questioned and adapted for ones personal circumstances. And this is a universal truth of live!
Concerning offshore voyaging I would spontaneously mention two other aspects:

Boat size and type.
(whats right for 50+ ft aluminium Morganscloud is not necessarily right for 31ft GRP Inua.)

Own experience level.
(although I might have a similar screw up tolerance as John has, I do not have the same experience level. This gives me a tendency to over-engineer if in doubt. – I hope.)

Rob Gill

Thanks John,
Very timely read and most valued. I was considering a combo – charger/inverter…and fitting a second alternator (vs a single up-rated one)! Why are we tempted by such thoughts? Down-under they would be called “Claytons” devices, named after a non-alcoholic beverage launched here in whisky shaped bottles under the slogan – “the drink you’re having when you’re not having a drink”:

So here’s my candidate for John’s list. Our previous boat “head” had 4 metre long pipe lengths, with constrictions and sharp bends to reach a holding tank situated in the aft lazarette of all places. This resulted in lots of system friction evidenced by high pressure at the toilet pump handle. It then needed an electric macerator with separate electric pump to drain the tank. The installer’s forwarding address was in Screw-Up City. Our new (to us) boat has a much simpler set-up with a hand-pump fed, gravity draining holding tank in a void space, just above the toilet and behind a removable panel. It uses a standard marine manual toilet pump, short hose lengths (nothing more than 1.5 metres) all the same diameter as the pump outlet and has only one sharp bend at the manual over-board by-pass valve. At 10 years (life) I replaced the whole manual pump rather than do a spares re-build (here it only costs 30% more to buy new). So for anyone buying a boat, I suggest checking the pressure on the toilet pump handle. If it is reasonably effortless, it probably will be. If it is hard to pump (or needs an electric pump etc), it probably won’t be.

Whilst on the subject, I have seen a self steering gear that doubles as an emergency rudder claim by the maker of Hydrovane. The concept of having a ready-to-go emergency rudder system, that happens to steer our boat without drawing power is worryingly tempting. But is this a Claytons emergency rudder anyone? and does the answer have something to do with my tolerance…?

Erik de Jong

Contrary to the picture that John sketched of me, I actually have a quite low tolerance for screw ups.
I have a few criteria for equipment that comes on the boat:
– It needs to be reliable with low maintenance time (I prefer to go sailing!),
– I need to be able to trouble shoot and fix it myself,
– If it does not comply with the above, I need to be able to go easily without, or I want a completely independent backup onboard.

My general policy, just like John, is to replace rather than fix. Except for the engine, there is no used gear onboard. This is a policy that my father taught me, and it worked well for him over the last 40 years, and 33 years/200k miles for me (first decade as a passenger I must admit). In all those years, I have encountered one failure that could have been a real show stopper, and that was the engine last summer.

So why opt for that old engine you may ask?
Well, cost is one, including overhaul and a replacement flown into Greenland, I’m still out at lower cost than I got quoted for various new engines at the time of built. But the main reason is that these good old Ford Lehman engines are so plain simple, that I can fix them myself any time anywhere. The old one that seized up had no less than 38.000 hours on her (came out of a fishing boat) and another 4000 hours after a rebuild in my own boat. I never had any issues with her what so ever and only a few hours of maintenance per year. The oil pump failure that caused my engine to seize up is extremely rare (at least, that is what I’ve been told by various experienced mechanics that know these engines), and could have happened on any engine, including a new one straight out of the box, so that has little or nothing to do with the fact that the engine is an overhauled old one.
I did have issues with the ‘new’ engine in the first month after she was installed, but they were more of an annoyance than anything else, the engine could certainly be trusted, otherwise I would not have continued north, none the less it did happen.

I can completely agree with John, what is right for one person is not necessarily right for another. If I were to do it again, I would do it the same way without having to think about it, others, John included would write a nice post about it and advice anyone never to go that route.

In the end the balance for me is based on: the fewer maintenance hours I have, the more hours I can actually sail the boat, the fewer dollars I have to spend, the fewer I have to work and the more I can sail. That is what a cruisers life is all about if you ask me 🙂

Kingsley Brown

I don’t think it can be emphasized enough, that one’s screw-up tolerance is usually based on one’s financial situation. Case in point is the example you raised about re-building or buying a new diesel engine. My wife and I own a 1980 boat with it’s original Westerbeke diesel. It runs flawlessly, however I am under no delusions that this will last forever. It may in fact end tomorrow. So, I have already done the research as to what I would replace it with as my preference would be for new. However, installing a new engine would require almost 3 times the initial cash outlay as a rebuild. And for me this is not a trivial amount. I wish it wasn’t, as my decision would be a whole lot easier.

Marc Dacey

Our boat, a 41-foot custom steel pilothouse cutter, came to us as third owners in 2006; she was built in 1988 and despite her “shippy” looks, has yet to see salt water. The diesel, a Westerbeke W-52, ran well enough, but had suspicious low hours (about 1,150 h) for an 18 year old motorsailer. I debated an overhaul, because I wasn’t going to go offshore without one, even given the fact that I could arguably run for 5,000-6,000 hours before I was likely to need one. This was because I had not winterized or maintained the engine myself for that time and it was a mystery how well that maintenance had proceeded.

Well, I found out that the cost of the rebuild of a 1980s marine diesel was slightly GREATER than the cost of a new, more efficient and somewhat more powerful Beta 60…so I did the swap. While I discovered that the W-52 could have been rebuilt with an Australian-sourced rebuild kit (it’s based on the Mazda R2 diesel found in Ford Rangers of the period) for a fraction of what I was quoted, I do not regret replacing the diesel because by doing this job largely myself (along with hydraulic transmission, AquaDrive, new shaft, new prop, custom stringers, etc. I feel quite confident about the whole power train and my maintenence regime is fairly regular. Just knowing is a huge confidence builder when one has clamped every hose and crimped every connection. So I would suggest that if you have confidence that you’ve done all you can to service your Westerbeke, that you find what non-marine block on which it’s based, and then determine if a rebuild *not from the marine diesel company* (who charge ridiculous markups) can be done for a couple of grand, instead of the $15K or worse some places will charge. Google is a huge help here: that’s how I learned my old diesel was still running on a ten thousand Aussie sheep farms in small, popular pickup trucks.

Neil McCubbin

When you say that you found our that the Westerbeke could have been rebuilt at a fraction of the cost of the new Beta 60, you were relying on an estimate.
I suspect that if you had actually done the job, the real cost and aggravation would have skyrocketed. Machinery that old invariably springs nasty surprises when dismantled. Also sourcing parts can be a nightmare.
Also, in our experience (2000 hours) , the Beta 60 is a very reliable engine.

Marc Dacey

I don’t regret our decision and we start a world cruise in three months.

Kingsley Brown

Thank you both for your comments. The engine I have is the W30 where the block is a British Leyland, one commonly used in their tractors and cabbies. Knowing this makes sourcing parts easier and cheaper than going through Westerbeke. That said, John’s comments really have me thinking that not replacing with new, is really false economy.
Regarding doing my own removal and install, I was planning on doing this anyway as you have suggested. I feel this falls within my level of competence and it would save a lot of money. Like Marc, if I have to replace I would also choose a Beta. (based on a Mitsubishi block)
Anyway, I hope it is a decision I don’t have to make too soon.

Marc Dacey

Well, if you have confidence in your abilities and in the basic soundness of the engine, and you have a non-marine source for parts (the critical bit where the wallet is concerned), that’s most of the battle, apart from getting the beast out of its lair.

Eric Klem

My own thoughts on rebuilding small diesel engines is that it can make sense if you do it yourself but I would never pay anyone to do it. With the cost of labor, you end up with something that isn’t that much cheaper and is going to be hard to find parts for. On larger engines, rebuilding can make a lot of sense, especially as these engines are often designed for it. Unfortunately, many rebuilds are not done properly which is very concerning. Doing a rebuild is not particularly difficult but you do need to be very careful about following all of the steps, cleaning/prepping all your parts and getting all your torques right.

Beta has a huge advantage for repowers because they will supply custom mounts. If I were to repower right now, this would definitely be the first place that I looked. I also like that they are open about what Kubota engine they are using.

Regarding rebranding of engines, the original model number is almost always cast into the block somewhere and you just need to look around to find it. Our own engine is a Mitsubishi K4D and when comparing parts prices, Westerbeke often marks parts up 2X+.


Dick Stevenson

Hey all,
If there is a need, I will definitely support not rebuilding an engine. Way back when I salvaged a sailboat which gave my family many years of pleasure, but only after we junked the rebuilt engine in which were left many gremlins timed to emerge at the onset of holidays.
Dick Stevenson, s/v Alchemy

Marc Dacey

John, one of the things I do to pay for my boat habit is editing, and I could let “separated at berth” *slip* by! Best typo of my day.

Dick Stevenson

Good morning John,
Yes, we bought the LeComte NE 38 as a blind bid insurance write off after it had been run up on rocks and largely sunk. I then proceeded to learn the multiple lessons you later spelled out as the fun and games possible on a handy-man special boat buy. The last lesson was replacing the engine I had had “re-built, good as new” with really new.
As to this twin thing, I will not admit to evil, but occasionally contrary does fit. And I do understand an irregular aberrant position on your part as necessary to establish independence.
My best, Dick

Rob Gill

Hi John,
Thought you might like this story from a friend only yesterday. A few weeks prior, he had taken their boat out to start a coastal race, in a hurry and with quite a bit on. There was lots of background noise including nav instrument alarms, he and the crew managed to overlook the oil pressure and engine coolant alarms which resulted in his cooking the engine. The bolts attaching the freezer compressor to the motor had loosened over time with the vibration of the engine, and so progressively sawing through the engine oil return hose. I surmise it was an “after-market” attachment and therefore not allowed for in the Volvo engine design.
Their insurance refused to pay-out as it was deemed a maintenance issue and not an insured event.
Net result was an engine replacement bill with no change from ~ US$30k. The other impact this time was lost sailing time and red faces all-round. It could have been much worse.

And this within 2 weeks of reading your “don’t junk up the engine” comment! This just entered our Boat Manual as John’s first law (of engine management).

best regards


I agree that everyone needs to take their screwup tolerance into account. Even new products rarely live up to expectations of many. I am one of those many. For example, a new small diesel will come with v-belt driven accessories when a serpentine belt would be a much better and reliable solution. Profit margin has driven quality to a rock bottom level. I have been driven to the point of doing everything myself because I am never satisfied with the mediocre.

Marc Dacey

I strongly agree with this. One would think that one would not have to reinvent the wheel with most marine gear, until one finds the wheel is pot metal and was cast on a Monday.


I kind of hate it, when I have to pay a professional good money for only mediocre results. Mediocre I can usually do on my own.

Marc Dacey

The difference, of course, is that when you eventually learn of the mediocrity of your initial repair or service, you can go back and redo it to the professional level, which itself is so rarely found at the so-called professional level.

Either way, half-assed by me is a lot cheaper than half-assed by those I’m paying.