Using a generator

Will be chartering a 50' mono at the end of the month. This is the first boat I have captained that has a generator. Would appreciate advice on when and how best to use as opposed to the old fashion firing of the engine, and further how to use in combo with running of engine. Thanks!

Typically, I will start the generator an hour before people start going to bed so that the AC can take some of the humidity/heat out of the boat. If you continue to run it through the night you should have sufficient charge on your house batteries to get you through the next day. I only run the engines to get in/out of mooring fields & marinas, so battery charging from engines is minimal. YRMV. <img src="http://www.traveltalkonline.com/forums/images/graemlins/Cheers.gif" alt="" />

And don't try to run the generator while underway. The cooling system won't be able to get water properly and the generator will overheat.

Use it anytime you want to run the A/C. Charter company will instruct you on its operation.

We run it all night, so no other need to charge the batteries.

I can imagine needing to run the AC in Jan/Feb. It'll actually be an option this year for the first time. <img src="http://www.traveltalkonline.com/forums/images/graemlins/Yikes.gif" alt="" />

'you should have sufficient charge on your house batteries" I would think most gensets have an invertor charger as well. To the OP, there is no reason to run both at engines at the same time. We use our generator more for charging then A/C.

Most boats in charter that have 2 generators will need both to run all of the AC units.

That depends on where the raw water intake is located.

I would check with the charter company.....very likely they will warn you (in most cases) that you are NOT to run the generator and engines at the same time. Before someone jumps...that has been MY experience.

All generators are not created equal....

however, most should not be started, make coffee, turn off

or

turn on, blow dry hair, turn off

I know it won't matter to the "charter captain" but it will matter to the owner.

It's possible the main engine and the generator were sharing the same through hull which would be a problem. Each boat is different and your briefer should know

<img src="http://www.traveltalkonline.com/forums/images/graemlins/Thumbsup.gif" alt="" /> <img src="http://www.traveltalkonline.com/forums/images/graemlins/Thumbsup.gif" alt="" />

Running a Genny at less than 60 - 70% of rated load will eventually end up causing Glazing & carbon build up. Starting a gen to just charge the batteries is a bad idea. Turning on the AC will load it and all is MO BETTA

I chartered with San Juan Sailing out of Bellingham once. Each owner had a nice write up of all the systems on the boat - he even had the engine rpm settings for best fuel consumption (it was a power cat). I felt like I already knew the boat before I stepped aboard and it was a great reference to have on the trip. I wish some of the outfits in the islands provided this! Hint, hint.

I don't think I have ever seen a charter boat with 2 generators? My 5.5 hp generator runs both A/C units quite well.

Maybe a mega yacht as a back up has 2 generators.

We've been on some of the bigger Voyage Cats, mainly the 58's, that have 2 generators.

how many A/C units, 4? 58 is a huge boat, double your trouble, double your fun <img src="http://www.traveltalkonline.com/forums/images/graemlins/Grin.gif" alt="" />

Yep, 4 units. 1 forward and 1 aft on each side.

Yes, the Voyage 52's and 58's do. Some of the 50's as well from what I know.
Chilly nights and no humidity.

We tried to run on a 50 with just one and it tripped constantly.

Most of the gensets in the current charter fleet are an afterthought and were not fully engineered in the original marine architecture. You will need to get a full brief on the boat for the hull you are on and generator actually installed in that hull. To assume two boats and installation are the same would be mistake. The proper generator and engineering should be able to run 24/7 with a daily check of oil and cooling levels. You will find few charter boats today with that configuration. There are issues with stop and start short cycles on any diesel engine. The same would be true for under and overloading of the engine. You should ask your boat briefer.

We chartered a 47 Grand Banks with NW Explorations in Bellingham. They emailed the captain the entire systems manuals and the same type of in depth pre charter info. It was great. We had the boat figured out in about 20 minutes. Great charter company for those of you wanting a fabulous NW stinkpot experience.

Hey Rita,

I almost went on but didn't want to sound like a salesman. But now that you mention it... her goes.

I loved it, sitting on a boat and looking at snow capped mountains. But, the water was way too cold for swimming! Customer service? Three things happened that impressed me. 1 - they did a barbeque once the afternoon chart briefing was over. 2 - I lost my house keys in the boat. They were found months later and the office contacted each charter until they found out who's keys they were and sent them free of charge. 3 - a starter solenoid went bad so one engine wouldn't start, one of their guys took a look and didn't understand why he couldn't diagnose it, he was calling an outside expert. Within 10 minutes a marine electrician showed up, diagnosed it and explained how this particular boat had two solenoids per engine and when I quizzed him on it he knew exactly why. Twenty minutes later we were off the dock. Oh, did I forget to mention the ferries up there almost always run on time? If you could only swim in the water they would take over the charter world!

There should be no problem running the genny while underway on a catamaran or while motoring on a monohull.

I believe that the risk increases with boat speed and location of fresh water pickup.

I have been told by charter companies not to run it underway but I think that one might want a technical explanation as perhaps running the generator at 6 knots is ok.

I can tell you for a fact that many moorings boats leave the dock with the genset running and return with it still running having never been shutdown. Still it's not a good practice and depending on the sea state and pickup location you can uncover the raw water intake.
George

Well, we were specifically told not to run the gen on our 474 PC.

I'd hate to return with a fried genset after being told not to run it underway.

It would be one thing if it was your own boat and you could experiment, but quite another when faced with a fairly complex bit of machinery (that is, the entire boat) for the first time.

Most generators today will automatically turn off if it overheats.
If they tell you not to run it underway they probably have a valid reason, there are other variables that can mess up the engine like siphoning water back into the block.

We were specifically briefed NOT to run the genset underway

backwash is the main reason not to run underway. Larger vessels obviously run 24/7, but are designed to do so.

Let me try again. It depends on the engineering and instalation. The difference between the generator and sea level can make a difference. Are the fresh water inlet and exhaust set up to handle the pressure differences when the boat pounds on and off the waves? Does the speed of the hull create a vacuum starving the fresh water inlet? Does the sea action take the intake out of the water? At what point of heel does the generator have oil flow issues? If you want to run a generator safety underway the boat must be engineered for that. Some are some are not. Many boats may seem just fine until you cross one of more of the wave, speed, heel danger zones.

The primary difference between running a generator and the main engine is the monitoring systems. Generators monitor temps, oil pressure, voltages, etc. If there is problems they shut themselves down. The main engine does not do this; you are responsible for keeping an eye on the gauges. Generators are designed to run unattended while you sleep, go to the beach, or whatever. Set it and forget it!

In my experience it is typically no problem to run a generator while sailing or motoring. If the boat is built to ABYC standards it should be no problem. (And again, it will shut down before it runs out of oil, water, etc.) However, if the charter company asks you not to run it while sailing for whatever reason you should probably respect their request.

Voyage has two generators in the 52 and 58 because they use a very small generator. They use. 6kw in all their boats. The 6kw was fine in a 44 foot cat with a total of 23.5 BTU's of AC. It was really marginal in the 50 footers even after adding a auto load shed system. Most cats in the 45 foot range have a 9k genset and 50 footers usually are 11.5 or more.
George

I know that it specifically states in the Leopard 46 (Moorings 4600) owners manual not to run the generator when underway.

A couple of physics issues are in play here. Backwash has been mentioned.
There is also a low pressure zone that forms at the intake, causing stress on the little rubber impellers. depending on hull, high pressure can form at the exhaust through hull.

Water beats air every time.

Newer diesel engines have the monitoring systems almost on peer with diesels. All my pressures and temps are on a common data bus to my chart plotters.

In short, if they say don't use a generator underway, don't.

Mr. Steve... you are talking about some boats and some installations, coupled with a whole lot of ASSUMEtions. That is a recipe for disaster or at least problems. The boat may be designed to all kinds or standards. That is no reliable path to insure the group that comes behind will maintain those standards when they shove the generator into the boat to meet a marketing requirement. A quick review of the installation manuals of most smaller lower cost diesel generators will show the units are designed to never have the exhaust underwater. Many of the BVI charter fleets heel to the point or have wave action above the exhaust level. In the simplest of arguments while most gensets are set up to shut down on their own at the sign of danger. The panels are set up so that most crew members will not hear any of the alarms from the generator while underway. The reality is most of us underway will not know the generator has any issues until it is too late and real damage has been done. All that said... many treat the generator and AC just like the one in the hotel. They turn it on when they check in and never turn it off. Next time you are dingying around the anchorages. Note the boats locks up with exhaust coming out. In much simpler terms if the single exhaust is any where near the water line. There will likely be issues in some sailing conditions running the generator underway. There is no simple way for most users to determine by sight any vacuum issues with the intake underway.

In the worst case conditions for the day will your exhaust stay above the water line or level? If the generator was meant to run with the exhaust underwater the boat builder or marketing department would have put it there. To get around this many boats exhaust the generator somewhere well above deck.

I have to agree, we also have a 2' loop in our exhaust. Yes, generators have gauges and monitors, but they would require monitoring. I can not think of one good reason to run a generator underway.

I saw the thread get a little technical below so I'm going to bring it back to basics. If you really know your stuff you can take your own chances but I tend to stick relatively close to the briefing instructions (and usually a binder that's provided with the boat).

1) your charter company will give a briefing and it should include how to use the genset on THAT PARTICULAR boat. With so many different boats they have to vary.
2) we've chartered 3 boats with gensets. A Moorings 54 mono 6 years ago and 2 different older 44' cats (Lagoon and Voyage) within the last year and ALL of them told us to NOT RUN the generator while underway. I don't remember why but I do remember the specific instruction.

The weather was so perfect it wouldn't have been needed underway anyway and the only time we needed to ramp it up fairly quickly was during a full day of rain when we were stuck inside with the hatches closed. Otherwise they would cool down in plenty of time for sleeping.