Electrical resiliency for Atlantic crossing

[Adelie]

Originally Posted by daletournier

Huh...what are you talking about? Is that just a rambling insult?
Most long range cruisers I know take plenty of fuel, yet, mostly you dont use it BUT it gives you options and can get you out of harm's way. Sometimes it's best not to just sit out there and wait for wind to arrive,sometimes it dosent matter and that's what I mean by options.

Insulting, no. Poking fun of Badadim, yes. PeguClub has 33gal fuel on a 30’ boat and Badadim tells him 66gal is not enough and that he used 210gal going to the Azores and that almost wasn’t enough. If you tried real hard you might find a way to put 66gal of fuel on a Bristol 29.9 but if you put 210gal on you would start having stability problems and there be difficulty finding room for minor considerations like food, water or sleeping below deck.

PC uses 1/2g/hr on a 30’ boat. That’s probably 5.5 or 6kt. Let’s say 5.75kt. That’s 380nm range. Drop speed to 4kt and range will be somewhere around 500-550nm. That’s plenty of range to get thru a high that has shifted into your path and you’d still have enough to motor into harbor at the end.

Badadim went to the Azores in 2wk, 336hr. That’s 2250nm from New York at an average speed of 6.7kt. Badadim’s average speed exceeds PC’s hull speed of 6.5kt.

Badadim’s average speed of 6.7kt is probably equivalent to 1.0*sqrt(LWL) or less. That means that the waterline length would be about 45’ or so, thus a boat of 50ish feet in length. Also hull speed would be about 9kt.

Let’s look more closely at Badadim’s trip. He got there with tanks almost empty. Let’s assume 190 of 210gal used. At 1gal/hr that means he motored for about 190hr. Using the magic of algebra to determine an equation and a spreadsheet to crunch the numbers quickly if average sailing speed was 5kt he would need to motor at 8kt to achieve the trip average. For an average sailing speed of 5.5kt he would need to average 7.6kt motoring. As a guess let’s say the Badadim would start the motor whenever sailing speed went below 4kt.

Whatever, Badadim has a boat with 4 x-5x the volume and carrying capacity of PC’s and wants to offer PC advice based on what he would do even though he is in a radically different situation than PC. Apparently he has no sense of the scale effects involved.

And you seem to agree with Badadim.

[stormalong]

Originally Posted by carlwk3c

Where did you get your “less than 1%” figure? LiFePo4 is much more common than that.
And for how many decades does it take to satisfy you? It’s been out there for quite some time now. I replaced my dying AGMs 2 years ago and the technology was over 5 years in the field then.
And, I didn’t have to replace my charging systems. (Yours must be quite outdated if they can’t be programmed to bulk and absorb at 14.4V and float at 13.5V
Are you a Luddite, or just poorly informed about the technology? BTW, there’s a newfangled thing called GPS. Are you still trying to navigate with LORAN?

OK Carl - I am a ludite. I bought my first GPS in 1992 - a Micrologic Admiral. I got rid of my last Loran in 1994. I lived aboard my Nordic 44 for 19 years and sailed over 133,000 miles. I circumnavigated from 1992 to 1998 and have done a lot more since then. I do all my own maintenance and have never had an electrical failure. I have rewired re-plumbed, re-rigged and re-engined I have also never had a major breakdown on an ocean passage. If that makes me a ludite than I am a ludite.

OK Carl. I see you have no boat or sailing information posted. Tell us your resume and why you are so qualified to advise someone that is about to do their first ocean crossing. And where do you get your statistics on LiFePo4 batteries?

[weavis]

As moderators, we do not really like disparaging or sarcastic commentary that is derogatory to another poster. Better to ask polite questions and have a discussion from viewpoint to viewpoint.

Oh, and its against the rules that were agreed to when joining. Mods are charged with the members working in compliance with the rules.

Jes sayin'.

[Pete7]

Originally Posted by carlwk3c

Where did you get your “less than 1%” figure? LiFePo4 is much more common than that.

I don't that LFP is more than 1% even in a sunshine state in the US a first world country or somewhere like a European country. That isn't to say we are luddites, fare from it. I and a lot of other owners are well aware of the advantages LFP could bring like half the weight and rapid charging. The reason it hasn't been widely adopted at present is the high start up costs and risk if something goes wrong.

Yachties are generally conservative, just look at the number in any marina still using a CQR. They therefore see the value of FLA or more exotic AGMs which if they did fail is still expensive to replace but won't bring the tears an new LFP bank would if it needed replacing after a couple of years.

The prices are coming down, most of us are on a 'watch and see' path. If the price and reliability comes down to say good quality AGM prices then we may see wide adoption.

Pete

[Pete7]

My suggestion to Mediator (OP) would be to pull the existing engine in the autumn and either have it reconditioned or replace with another second hand engine. There is plenty of time if the trip isn't starting until next year.

The hint was mentioned earlier in this thread, sailing in the med unlike the Caribbean is no wind interspersed with short periods of too much wind. A reliable engine is a must IMHO. The cost of an moderate LFP set up likely to similar to a recon engine but the engine will be far more useful.

Pete

[B23iL23]

This makes the most sense to me. You need a good, reliable engine for the no wind days and for charging. Get this sorted and then you can look at your battery setup and see how you can improve it, if needed.

Originally Posted by Pete7

My suggestion to Mediator (OP) would be to pull the existing engine in the autumn and either have it reconditioned or replace with another second hand engine. There is plenty of time if the trip isn't starting until next year.

The hint was mentioned earlier in this thread, sailing in the med unlike the Caribbean is no wind interspersed with short periods of too much wind. A reliable engine is a must IMHO. The cost of an moderate LFP set up likely to similar to a recon engine but the engine will be far more useful.

Pete

[wingssail]

Originally Posted by Mediator

I'm preparing my boat for an Atlantic crossing (northern route) next summer. Lately I've been thinking about our electrical resiliency and I'm curious to hear from others who have made ocean crossings.

We have about 1kw of battery capacity supported by 350w of solar panels and our engine with a single alternator. Navigational equipment, electric autopilot, fridge, and freezer are our largest electrical loads. With normal sunlight, we will deplete our battery bank in about 5 days if we don't run the engine on a passage.

I consider our engine (1988 Perkins 4-108) to be fairly unreliable. If it fails halfway through the trip, or if the charging equipment related to the engine fails, then we will have to choose which electrical systems to sacrifice to maintain power for the remainder of the voyage. We would most likely turn off the fridge and freezer, some of our nav equipment, and hand steer during the day. That should reduce our electrical draw enough to run our critical systems with solar alone.

How long could you maintain electrical power without your engine? Is this an acceptable level of risk? We will install a second alternator and (most likely) a Monitor windvane before we depart, which will significantly improve our electrical resiliency.

Thanks as always to this great community

You have two issues to address:
1. Reliability and back-up.

• You say your motor is unreliable. You should address this if possible. Having no motor is a big compromise. I don't mean replace, but a thorough check-up and R&R.
• You have an alternator. I'd say you should have a spare, and regulator, and belts. Installing it ahead of time is not necessary.
• You have an autopilot. How about a good windvane (servo pendulum). This will also help you in the second issue (below).
• For back-up, emergency, electrical power I'd recommend a portable generator.

2. Electrical usage higher than solar supply.

• Yes, you need an energy budget. Your usage seems high to me. Where is it going?
• A windvane will reduce your needs.
• Try to manage the refer/freezer
• Get higher charge rates from your engine by using a higher (small frame) capacity alternator and a good multi stage regulator.

Your battery and solar capacity sounds OK, I am surprised it isn't enough. The energy budget will probably be enlightening.

Don't pack your deck with rows of jerry cans. You have a good sailing boat. Plan on sailing it and have patience when the wind is light (when the wind is absent we run the engine in slow or idle speed, just to keep enough headway so we are not rolling and drifting in circles. This takes very little fuel). Planning on motoring for days on end with a dodgy motor is asking for trouble. I'd say that 66 gal is plenty, we've never carried more than 60 in our tanks and two jerry cans, and have most of it still on the boat at the end of every ocean crossing. Your fuel consumption will probably bee less than .5 gal a day for charging.

[JPA Cate]

@Mediator. How much electricity would you save running the freezer as a fridge? If it is enough, then find out where you can get your meats (if you eat meat) vacuum bagged. It will all keep longer than the crossing. We have kept chicken 3 months with no problems, if it is vacuum bagged; also with beef and lamb. Even sausages and bacon can be vacuum bagged. If you use the freezer for bread, consider a long-life supply of flat breads for your "sandwiches," and made them as "wraps." Porridge for breakfast does not require toast, nor does hot cakes. Cabin biscuits make reasonable bread substitutes for voyaging. Our first year out, we did not have any refrigeration at all, and I liked my tinned butter and raspberry jam on my cabin biscuits. Used them open faces with many different spreads. Don't know how many crew you'll have, but a three week trip if you're baking bread, the baker will bake a lot, maybe 6 times.

Make sure the old Perkins is reliable, that is doable, and worthwhile, too. Spare alternator just in case.

To me the little genset and a jerry jug of fuel make sense for an emergency backup. PLus if you get used to using the Monitor, and don't expect it to steer like an electronic a/p, it will steer the necessary average courses, silently, and with 0 power drain. It does take some practice to learn how to get them to steer well, but windvanes are wonderful, but practice, and a clear air flow to the "feather" are necessary.

Arranging life so that the fridge/freezer is pulled down as far as possible before nightfall is a good idea. If there are easy ways to increase the insulation around the boxes, that will help, too.

Have a super trip when you go, and i hope you enjoy getting your engine tippy top: it's the kind of work one dreads, but then feels really good about when one is finished. And our guys here, will help with questions--and so will SaliorChic34, who tore down and rebuilt her boat's engine a couple of years ago.

Ann