Yacht Rock

October 26, 2014 at 12:37 pm

Just seen Tesco’s have a Yacht Rock CD for £9.50. Looks like there’s some classics on there… I actually have Hall and Oates ‘I can’t go for that’ on vinyl (it actually drops a quite nicely into a chuggy house set)

According to Wikipedia, Yacht Rock is both a music genre and an American ‘mocumentary’ about the fictionalised lives of  American soft rock stars of the late 70s/early 80s. I’m imagining soft rock Spinal Tap… I’ll see if I can find it anywhere.

Before then though, I’m going to go listen to Hall and Oates

Yacht Rock

12v Power Calculations, Part 2

October 21, 2014 at 12:45 pm

Way back at the beginning of the year I calculated Duet’s power consumption requirements, and I figured that she needed 2 x 75Ah capacity (size) batteries and had a power consumption of a maximum of 50Ah per day.  I was looking at a wind generator and a 20w solar panel for charging. You can see my original blog post and calculations here.

Well, that was all quite pricey and I ended up just keeping my 1 year old 75Ah battery and adding a new 20w solar panel on the lazarette locker lid. In practice it worked better than I thought it would, and actually between leaving Portland and lifting her again in Plymouth 9 weeks later I only actually charged the battery from shore power once.  The solar panel seemed to keep it pretty well charged, topping the battery up surprisingly quickly even on overcast days. But, I was very frugal with the electronics on passage… I kept the VHF off most of the time, used a battery powered GPS and if there was shore power available I made sure that my iPad and cameras were fully charged before we left again.  And then I did a night passage from Helford to Plymouth. And the lights died before dawn as the battery was flat!

Clearly I do need to look at this again… So this first table shows what I think I need for an average coastal passage, or more precisely what I needed for the Helford-Plymouth passage.

It has the following assumptions:

1) Maximum time at sea is 18 hours as my longest passage so far is 15 hours so this is plus a bit for contingency.  On a coastal passage I probably wouldn’t want to do much more than that on my own too often.
2) I want to be using the Garmin 128 GPS, rather than the handheld one as it was very thirsty on batteries.
3) The radio used to transmit has a much higher power consumption than receive or standby.  I will be using the radio at a minimum and haven’t factored for any radio use.
4) In the daytime I am a lot more relaxed about not having the radio on, but at night I would probably want it on standby listening to traffic. I’ve calculated for it to be on for 15 hours. Standby for 13 and receiving for 2. This assumes there’s not that much traffic.  If there’s lots of chit chat or numnuts running out of petrol it annoys me and I turn it off (unless I’m bored ;o)
5) I have already replaced Duet’s old navigation lights with an LED masthead tricolour which tested working OK on the ground, and again when on deck ready to be stepped.  But by the time the mast was raised it didn’t work, and I couldn’t get it going all summer (Grrr!).  I am assuming the fault is with the connection at the top of the mast and I will get it going! It draws a fraction of the power of the old bulb lights.
6) I’ve searched on google for the power consumption of each piece.  This does assume that the wiring is in good condition, as if it’s not the resistance is higher and the unit draws more electric. I know Duet’s wiring isn’t great, but I will be replacing most of it this winter, and the mast was rewired earlier this year. So I’ve gone for best case, as per the manufacturers specifications.
7) There is no electric autohelm allowance on here. I’m still toying with this… and I don’t have any cabin lights, I just use a paraffin lamp.

12v Power Calculation Hurley 22

Coastal Passage Power Consumption

So this is showing a total maximum power consumption of 33Ah a day. As you should never draw more than a third of your battery then 33 x 3 = 99Ah – I need a 100Ah leisure battery.

I would also need to replenish up to the 33Ah.  My 20W panel should replenish 10Ah a day (see previous blog post for calculations), and I also have a 60W charging coil on the outboard which works out to replace 5Ah each hour it’s run. In practice, that night from Helford to Plymouth I actually ran the engine for 7 hours… so if I’d had the engine charging connected I might well have been OK with the lights.  If I add another 20W solar panel to the forecabin hatch, with 40W of solar I should get 20Ah and if I run the engine for just 2 hours on a passage you can see we’re up to a potential 30Ah and are nearly there…

Conclusion: 100Ah battery plus 40W solar plus engine charging needed

But, if you’ve seen my winter 2014/15 maintenance list you can see I want to do some more upgrades and make her a bit more ready for longer, more “offshore” passages. As a base line I’ve done this second table to work out what I would need to give me enough juice to do, say, a 3 day passage across the Celtic Sea… (perhaps, just maybe, leaving on 14th June?)   So this table shows what I would run over a full 24 hour period at sea, but tactics are a little different:

1) I would turn off the radio once clear of the coast, but have allowed 4 hours use per 24 hour period (3:1 Standby:Receive)
2) I would turn off the log/depth and GPS most of the time, only turning it on intermittently for recording in the log as out of sight of land/rocks there is more of a margin for error.
3) I would be using wind vane self-steering and probably turn off the wind instrument  most of the time.
4) I do intend to fit a NASA AIS and would have this on all the time (more on this in another post). It only draws 0.05Ah though.
5) This assumes 8 hours of darkness. In summer in the UK it is less than this.

12v Power Calculation Hurley 22

Offshore Passage Power Consumption

So as an exercise you can see the dramatic effect this has had: I’d need a maximum of 14.2Ah! Times this by 3 then I’d need 43.6Ah of battery, except they don’t come that small so I’d have a 75Ah leisure battery …but 20W of solar alone should replenish 20Ah and easily cover it.

Conclusion: Existing 75Ah battery plus 20W solar should be adequate.

Clearly this is very frugal, and not to everyone’s taste but it’s an interesting exercise. I am definitely cutting my coat according to my cloth, but on a small boat with no diesel inboard and alternator I think I pretty much have to. But I will upgrade to a 100Ah battery, add another 20W solar panel and wire the outboard in, which should just about cover me for the coastal sailing that I’ve done this summer.  I’m pretty sure this isn’t the end of this story though…

Adding another 20W panel should be fairly straightforward, as it just needs to be wired into the regulator. I’ve already decided to put it on the forehatch rather than have a flat one on the pushpit or something. Wiring the outboard is a bit more tricky, but luckily there is already a socket there as the previous engine was wired in for charging so I have a head start at least.

Oh and if you think you’d find my calculation spreadsheet useful, click here to download it and then you can amend it for your own setup.

Very Superstitious, Writing’s on the Wall…

October 17, 2014 at 12:06 pm

There has to be rules and procedures on a boat.  There has to be order in case something untoward happens so everyone knows what to do, and the pliers, or knife, or bolt cutters have been put back in the correct place, and the quick release knot has been correctly tied on the liferaft etc.  Efficiency (and safety) on a boat is mostly about procedures and tasks being correctly completed (skills), proper maintenance (discipline), and planning for the unforeseen (strategy).

But at sea there is much that you can’t control, and anyone who ever spends any time at sea will gain a deep sensitivity to the raw fickleness of the elements, and just how quickly it can change. I guess to help regain some sort of sense of control, sailors were (are?) a superstitious lot.

I find these old superstitions rather fascinating… And there are lots! I’ve put this list together:


Sailing Superstitions


But how did these seemingly rather random superstitions come into existence? Presumably someone once did one of these ‘things’, and then something bad happened, and the ‘thing’ got the blame. That’s my logic anyway, and it gives me a vivid image of someone sinking after taking the vicar round the bay for a Sunday afternoon jolly.

The observant amongst you will notice that there is one very well known one missing.  But how can I possibly have ‘No women aboard‘ on here?

Have I missed any others? Do you know any more?

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