use of Generators and windlass'

Dual generators generally are not there for more power, but for redundancy.

Some boats have them as identical others, like mine, have a smaller genset which is quieter if running overnight.

The other advantage of dual gensets is that it effectively doubles your time between servicing. A single generator can quickly pile up the hours and require servicing long before the main engines are due.

Overall however, their main purpose is redundancy.

Regarding anchors, I have a 176lb anchor on my 120,000 lb boat ... and a second one alongside it ready to go. I have spent over 500 nights at anchor and I like my sleep.

I don't necessarily think the anchor is light for an 85' boat. We have similar size on our 85, but two, both with 300' of chain.

However, we do have two generators and we don't anchor nearly as much as others. However, with A/C, freezers, refrigerators, laundry, having a generator out of service if only having one would really be an issue. Running generators 24 hours a day, definitely feel the need to have redundancy.

The lack of redundancy on both items would make me look carefully at all other areas of the boat and see what redundancy might be needed that is missing. We're talking a boat designed for long range cruising so it's definitely important.

Anchor size is ok. I would definately want 2 generators on an 85' and both generators the same size/type so they share/use the same spare parts. That way you can rotate their use, if you're anchored/cruising for a couple of weeks it extends when you have to service them. Quite frankly I don't think I'd buy a yacht over 70' without a second generator.

If the "OA" stands for Ocean Alexander, their 85-footer comes with 2, 32kw Kohler generators.

One purpose in having two generators, aside from redundancy, is that they handle different loads. A "night" generator, meaning the smaller one, prevents underloading the main genset when only light load is required.

I have seen it on a bunch of yachts and the small generator NEVER gets used. The only time I'd want one is as a 3rd generator line a Northern Marine I used to run had. It's inadequate if running HVAC, it's inadequate if cooking, so in my opinion on most yachts, I'd rather have 2 equal size generators that can handle the entire boat, and a nice inverter bank instead of the smaller gen. Then in the morning or at dinner, fire up the normal sized generator and even without HVAC the battery charger load of recharging the inverter bank and the water heater will keep a good enough load on the generator. With LED lighting and no HVAC you could easily do a nice inverter bank for perfectly quiet sleeping.

Are you kidding me? Your post is almost bizarre. I have read it several times to try to find redeeming features but keep finding more per sentence to dispute. Let's not derail this thread with our disagreements; so I won't be responding, but I hope anyone reading your post researches the issue of different size generators as appropriate rather than relying on the bunch of boats you've seen.

I'll clarify, on most yachts with a large and a small generator. Let's say a 65' yacht such as the Searay L series....Main generator is 20kw and small generator is 9kw. The 9kw is not big enough to run the boats normal equipment (battery chargers, refrigerators/freezers, hot water heater, sat tv, and a few other minimal this and that's AND run the air conditioning pump and an a/c unit.....Or you may run 1, but if the a/c pump cycles on while the hot water heater is heating, it will typically pop the breaker. You also typically don't have enough electric to run a water maker with all of the boats equipment either, nor stabilizers, nor the oven, nor more than a burner or two on the stove. A 9kw puts out 32 amps of electricity, not a whole lot for a 65' boat that has 100 amp shorepower service.

You put an inverter bank for at night, and have NO noise and no exhaust or CO worries. Then have 2 equally sized generators that share the same parts, can be run alternate days to double your service interval (in hours), can run everything you want during the day, washer/dryer, a/c's or heat, watermaker, cook etc. etc. And if it goes down, you have another one that will carry the entire boat. Best of both worlds.....utter quiet at night and perfect comfort during the day. A toaster uses 13 amps, a hair dryer uses 13 amps.....turn one of those on while the hot water heater is working, such as right after taking a shower and blow drying your hair and the normal yachts equipment, and you overload the 9kw generator, pop the breaker, lose power and have to go into a hot engine room to reset it. No fun and a pain the rear. Take the dinghy out for the day and find the breaker popped and melted ice cream, no fun either.

The Northern Marine I ran spent a good amount of time in Washington....the 8kw had less than 60 hours on it (it had 2-20kw Onans that had well over 1000 hours each). I recently looked at a 2007 68' Lazzara and it's 9kw had 20 hours in 8 years, the 26kw had 2600 hours. Every yacht with a little generator never gets run. The 75' Hatteras I ran for many years and did the great loop with had a 20kw and 27 kw....the 20kw would carry MOST of the boat so we'd use it alternating days.....but always without fail, once a day we'd pop the breaker on it by overloading it..even when it was cool out and the a/c's or heat were hardly running...something would kick on while other heavy loads were on.......it was a pain......

My idea of yachting isn't cruising around with a smaller generator running to save 1/3 of a gallon of diesel per hour and going without HVAC and basically camping on a yacht......

If we're referring to yachts more or less 85' and under, the idea is to have a main generator, a smaller generator, and inverter (s). The smaller generator is specifically for lighter loads, so the references to running the whole boat obviously don't get it. The smaller generator provides redundancy in that you can run some air conditioning or the electric stove or the washing machine or the hot water heater, and of course depending on size, various combinations should you lose the main generator. The inverters are for quiet running. The point of my original post was to say that, aside from redundancy, a smaller genset assures that the big genset isn't underloaded when lighter loads are needed.

I found subsequent posts to be just as illogical so I took advantage of being at the Miami Boat Show from which I have just returned. I spoke with the Corporate Trainer and the Service Manager of Northern Lights. I explained how I thought the generator systems should be utilized and he agreed. Better yet, I then pulled out my phone and showed him this YF thread. He read my post and agreed with it, and then the subsequent posts and said, "they are wrong." Generators should be run, yes the new ones are better but the same rules apply, at a minimum of 50% load. "Less than that and you will get wet stacking and glaze the lines and subsequently require rebuilds." He then said that presenting information is probably not going to change someone's mind that is already made up.

It's not often, if ever, that I respond to posts so aggressively, but I knew that the posts, especially sounding emphatic and authoritative, could be detrimental to someone asking about the use of single or dual genie setups.

Judy

Well, the Northern Lights representative may have agreed, and he should certainly be considered expert, but I think this points out how many different scenarios there are and perhaps how many opinions. We have two boats with Northern Lights and both have two identical generators. But what about smaller boats. Northern Lights literature says "A generator should never run with less than a 25% load. 35% to 70% is optimal." While their representative in Miami may say 50%, as a company they don't. Their representative may say under 50% will lead to wet stacking, corporately they say 25% is safe. Now that still doesn't tell you who is right, but that there are conflicting opinions and one has to choose whose to go with.

I also went through this discussion on a recent purchase we were thinking about and the small unit's sizing was such that there was virtually no circumstance in which we could run it and not be overloading it. We tried to determine if there was a situation in which an inverter would not be enough but the small unit would be. Much of it depends on what you equip the boat with and your personal habits. Will we anchor for the night and turn the A/C and heat off? We won't. Many do, but we don't. How many refrigerators and freezers. Now in that case the two units were 29kw and 9 kw.

Another factor that comes into play is available space. If your primary is 29kw, space for an 9kw might be easy to find and 29 not so easy. So, if 9 isn't enough do you perhaps go with 16 or so for the second.

I must say though that in these discussions we've been involved in 50% has not been the target, not with Northern Lights, not with Onan. I don't think generalities can give you a right or wrong. I believe there are circumstances in which various combinations might be most appropriate. I think one must be very careful to involve the manufacturer of the generator, the builder of the boat and to do very specific calculations of loads and needs.

My quote was from Northern Lights' buyers guide.

http://www.northern-lights.com/media/PDFs/misc_pdfs/buyers_guide.pdf

We have two 99's on one boat and two 33's on the other.

Our manuals read much like yours.

This is the point I'm trying to make. Also, even at night there's always a good enough load, when you're on a trip every freezer, refrigerator is on, every ice maker, water heater and this' and that's, water maker, laundry, you name it. I rarely see a generator under 50% (main generator), even at night. If you have a generator running you have bilge blowers going as well. If running for the day, a lot of engine room heat radiating through walls so a/c's are working.

If the big generator goes down, yacht owners want the other generator to supply the whole boat. If you aren't using hvac, then an inverter bank would probably cover it and be totally quiet instead of a small generator that is usually louder than the large one. Therefore I'd rather have 2 equal size generators and a nice inverter. One owner once told me, If I wanted to go camping, then i'd go camping and save millions of dollars. I bought a yacht to go yachting and I want to be comfortable.

NOW, I believe trawler owners are a different breed and split two nickels to make a quarter. One on a 50' Kady krogen couldn't understand why he should paint his bottom that hasn't been painted in 4 years before doing a trip from Ft. Laud to the carribbean and back over a year and how it would save him money on fuel by being more efficient or at least it's cost.

If you have diesel heaters and the boat is in the Pacific Northwest, I could see a normal sized generator and a small one. But not anywhere tropic.

Honestly I have no idea where you got the idea of what 85' and under should be equipped with. I work with several different builders and only 1 routinely equips their boats with an inverter. Oddly they also equip their boats with equal size twin gensets.

West coast boats often have inverters since they often don't need to run hvac systems at night. Marquis was one the of the few builders that had factory installed inverters on their 59'+ boats. Viking, Bertram, hatteras, Cabo, Searay, Pershing, Ferretti, and countless others did not.

Dual gensets are options on many different boats, some use equal sized units while some use a smaller secondary. What's ideal depends on the owner's requirements. Most boats heading to the Caribbean and South America (from what I've seen) will have either like sized or very close for the sake of redundancy.

It all really depends on the boat and how it's going to be used. I will call bs on having to keep at least a 50% load on the genset though. If your light load is 50% then you are most likely tripping breakers at max load. "Oh chiller plant isn't running, better start the aux and switch over so I'm not below 50%". Sorry but that's just silly.