Engines, Safety and Monitoring

Some of you may have noticed that the frequency of my blog updates has started slowing down. My guess is that over the next couple of weeks I will not be writing much. Everyone is hard at work finishing off the boat, in preparation for our departure. There aren’t a lot of decisions to be made at this point. Most trip preparation, and most boat upgrades are finishing up. We are entering the “calm before the storm” phase.

Lots of work is taking place, but it’s all stuff I’ve talked about before. This morning, I sent an email to Jeff, who is managing the project, that began with the words “A glance at the calendar shows we only have two more weeks before I return to Seattle…” and finished with the words “Perhaps this would be a good time to consider working long days and weekends.” All is on schedule, but there is an enormous amount of work to be done.

As some of you know, I have two mailing lists for my blog. A “small list” which has only a few hundred people on it. My blog updates are read by these people, as well as those who visit the website daily (www.kensblog.com) and those who receive it as an RSS feed. There is also a much larger list, which has been compiled over the years. The people who have been reading my blog daily over the past six months are, for the most part, a more technical group than the larger list. Mentally I think of the smaller list as the “hard core boat geeks”, and the larger list as the “persons with a casual interest in boating”. I don’t mean to be unfair to either list in that there are certainly plenty of exceptions, but this overall characterization I think is fair. My policy has been to only send out my blog, when I’m not on the boat, to the smaller group.

Very soon now, that will change. Next week, I will merge the two lists, and send out the first update that goes to the combined list. Some of you may notice that my blog will get slightly less technical, and slightly more travelogue-ish. You’ll also notice that I rehash some old topics that have been covered over the past six months. My apologies in advance. Many of the people on the larger list haven’t the vaguest idea that Sans Souci is going to Japan. The last they heard, we were stuck in Costa Rica.

So .. expect to receive a confusing blog entry sometime in the next week or two. No worries, I’ll just be spinning all the “big list” people up to speed.

And, with that bit of bureaucracy out of the way….

I read several different message groups, almost every day; Passagemaking Under Power, World Cruising, Southbound_Group, Sail_Japan_Open_Forum, NordhavnDreamers and a bunch of others, including some, like the Nordhavn Owners Group, and the Nordhavn Big Boats group, that are not open to the public. There are days when it seems like a waste of time, and there are often days when it is time well spent. I suspect all of you who read my blog know how that feels.

Today, on the NordhavnDreamers board, there were a couple of topics that were fairly thought provoking. These always send me off googling, and I usually finish by learning something.

One topic had to do with selecting the right engines for a boat. The discussion kicked off when someone asked whether or not my boat was “over powered” given that I have twin 340hp continuous-duty rated engines, for a total of 680hp, and yet, my boat achieves hull speed (the maximum speed realistically possible) at under 350hp. In other words, my engines are always running at under 50% of their rated capacity.

I responded by saying that perhaps I could have gone with smaller engines, although I like the idea of knowing that I can still run at my maximum speed, even on a single engine.

Someone then commented that there is a general rule of thumb which says that most engines burn a gallon of fuel, for each 20hp delivered, regardless of the engine’s size. In other words, if you know the fuel being consumed, at a given speed, you know how many horsepower it takes to push the boat through the water. For instance, at 9.5 knots, I burn around 12 gallons per hour, or 6 gph per engine. This implies that it takes 240hp to move my boat at 9.5 knots. This 240hp is the same regardless of the brand of engine, whether I provide the power with a single engine, dual engines, large engines or small engines. It does vary a bit, based on things like the pitch on my props, how clean the bottom is, and a million other variables. This ”rule of thumb” isn’t exactly accurate, but it gets you close.

Here’s a few excerpts from the discussion which I found educational:

“…It’s not the high HP engine that burns fuel, it’s using the HP
that does it. You get the burn rate you ask for based upon boat speed all other
things being equal. I 100% agree. Big engine or small this rule holds…”

“…In my view the best thing for a Nordhavn is a large, under-stressed, continuous
duty engine (or the closest thing to it) run conservatively…”

There were also a couple links to great discussions on diesel engines, and maximizing engine life and fuel efficiency:

· http://mvdirona.com/TechnicalArticles/DieselEngineOverload/

· http://tinyurl.com/dj6ogs

The bottom line seemed to be that I am not really wasting fuel by having over-sized engines, and that by not overloading the engines, I am likely to have long engine life. Good!

The other discussion I found interesting had to do with safety.

Here’s the slightly abbreviated original posting:

“I have been reading and following the postings on this group for some time now.
It is probably folly to compare “sailing” and “flying” but will try. We in
aviation always play “what if” games or at least the old and bold pilots do.

[…]

To not have an anchor ready to drop on 10 seconds notice when approaching a
lock/bridge with a following current is […] “troubling”.

How many skippers can use a sextant?–I used to teach the use thereof and still
have mine and believe it or not, use it a few times each year. What if you are
mid ocean and loose all electricity? It’s happened.

These are examples of “what if” that should be played out in your mind.

You do have made up hydraulic hoses and know how to remove and install? Right?
Oh…….how about fluid?

I spent many, many, many years at the airshow in Oshkosh working the most busy
and dangerous area at the show. I have seen pilots walk up their million dollar
bird and climb in without the least pretense of a preflight after 100,000 plus
people (yep that many if not more) have walked around and under it. I have
seen pilots get ready to start 1000 plus hp engines with tow bars in place,
placards over engine openings, flat tail wheels, gust locks in place, bomb bay
doors open, wing folding struts and locks in place and hundreds of other dumb
stunts.

The purpose of this rant: Egos are fine (we all have one, some bigger than
others), undirected egos will kill you faster than you can believe.

Oh……..I spent my working life as a lowly safety engineer and product
liablilty specialist and have sat in on too damn many accident review and
investigation boards.” – rf8gvfp63

Before I comment on this, I’ll share another Nordhavn owner’s response (John Marshall):

“Good points… it’s interesting to walk around your boat or stroll
through ER and ask yourself all the “what if” questions, using the old
aviation standby of identifying single-point failures… i.e any
failure that could disable the boat.

What happens if rudder attach bolts fail? Can you drive for days or
even a week with a hand tiller?

What if rudder feedback device(s) fail (something few people think
about)? Can you run without an autopilot for a week or so (halfway
across an ocean)?

The list can get really long, and is both interesting and
“troublesome” for most of us.

Your hydraulic line example is a good one. How many of us can
realistically cope with having a hydraulic line on the steering fail
and drain system? Every Nordhavn I’ve seen has a single hydraulic
steering system (albeit with redundant cylinders and AP’s). But if the
Hynautic system develops a bad leak, you have to use the hand tiller
until you can repair.

I don’t have spare lines made up. I don’t carry more than a quart or
two of Hynautic fluid. I have never diagnosed or repaired or bled air
from my steering system.

Losing rudder control is equal to losing propulsion in terms of
disabling failures. Hand tillers are useless without block and tackle
rigged, which the boats are not set up for.

That’s “troublesome”.

John”

A lot to think about here. I “think” that I could deploy an anchor in 10 seconds if I needed to, except that in reality, I couldn’t. My engines provide the hydraulic power, which in turn provides the power to my anchor winlass. In other words, if I lose all propulsion, I’ve probably also lost my ability to drop anchor. Ouch.

And, as to the hydraulic system: This is the one area on the boat that I’ve never had to mess with, on this boat, or on my prior boat. The hydraulic systems, once they are dialed in, rarely fail. But, “rarely” is not “never”. If I had a major hydraulic leak, I don’t have the spares, skills or tools to really deal with it. If I had a major hydraulic failure, I’d be in deep (censored). I do have a manual tiller for my boat, but it isn’t very practical. Obviously hydraulics are an area where I need to get smarter. Argh. Each time that I think I have the skill-set required for offshore cruising, I find another skill that I need to develop.

And on a vaguely related topic…

A few days ago I mentioned that I was reading the book “66 Days Adrift” about a couple who spent 66 days on a raft after their boat struck a whale and sank. It was recommended by one of the blog readers, and seemed like it could be a good read, which it was. I had hoped that I might learn something from reading the book. However, at the end, I don’t know that I really learned anything useful.

In the book, the couple took their epirb along with them to the raft, but then found it useless. That wouldn’t be true today. They had a battery operated epirb (emergency transmitter), that relied on transmission to a nearby aircraft or boat. The batteries ran out long before they were able to use it. Modern epirbs transmit directly to satellites, with immediate notification to the Coast Guard of who you are, and where you are. In reality, we’d probably use the sat phone to call for help before stepping into a raft, or shortly thereafter. Safety has come a long ways over the years.

One thing that was interesting, and surprised me. They had an endless series of shark attacks. On our Atlantic crossing, we stopped for swimming a couple of times, and never saw a shark. The book talks about 40 to 80 shark attacks a day! They rebuffed the sharks by smacking them in the nose with an oar. I can’t imagine trying to sleep while constantly having a raft pushed around by sharks. Amazing, and very frightening.

And on a completely different, and more practical topic…

I spent Friday talking to a variety of people about adding additional monitoring to Sans Souci’s electrical system.

I have a system on Sans Souci (called Simon) that is constantly monitoring various sensors around the boat, allowing me to see what is happening at 200+ sensors, instantly, without leaving the helm. In addition to allowing me to see what the sensors are reading,, I can also set triggers, such that the Simon alerts me if it sees any values that are outside the “normal” range. For instance, I might tell it that the normal shaft bearing temperature is 95 degrees, and that I’d like to know if the temperature exceeds 110 degrees. This doesn’t replace the need for engine room checks, but it does add to the probability that if something goes wrong I’ll be able to react before the problem becomes severe.

 
Note: These photos are not from my boat’s installation of Simon