We are chartering a cat (40 ft). Part of the lure was to have A/C. But we have been told to only run the generator for 2 hours morning and evening. We never experienced this before in our two previous cat charters. Is this a common restriction?
Thanks

Sounds like the advice you got was specific to keeping the battery charged. If you have AC (and it is powered by the genset - some AC is shore power only), then it would be kind of unreasonable to expect you not to use it. So I don't think it's a common restriction.

Please just don't run the generator underway.

Sounds like the charter company simply wants to extend the life of the generator and extend the time to the next oil/impeller/filter change - the boat's owner will appreciate this.

For what you are paying for this rental.....
use the generator!

Can I just ask about this? I know people that use their generator underway, one even pretty well all the way on an Atlantic crossing so the sleeping crew were cooled while off watch, this was a large (65') catamaran; is there any or manufacturers reason why you shouldn't run your genset underway?

It depends on the boat and the installation of the generator. The bigger the boat the more likely it will be fine. Smaller cats can easily get the water pickup out of the water coming off waves when sailing fast. It was a problem on my Voyage 440. It’s not a issue on the Leopard 50. Having said that if you want to have nice cool air at night sleeping and minimize generator issues start it in the evening and shut it down in the morning. No need to run it during the day. You increase your chances of something going wrong, impeller failure, sucking in debris ect… The generators also typically require a 100 hour oil change and if you run it all the time you will exceed that early on day 5.
On the restriction given to the OP for run time it’s not normal. There is no point in having the Genset at all if you are going to do that. You are essentially chartering a boat without AC and that should come with a very large discount. It’s possible the generator is not sized to run the AC in which case the boat should be advertised as dockside air only.

Edit: Checked the Genset manual for my boat and only the first oil change is 100 hours. It’s 250 after that.

OK thanks everyone. From our point of view, the boat was chartered with AC that could be run at anchor. Both units will run for a couple of hours then the port AC trips it’s breaker. The two hour rule came after we queried this problem.

For sure we don’t run the genny underway (as instructed by the charter company).

There is something wrong with the port AC causing a higher load. If you are still on the boat check the filter baskets/strainers on the water intakes and the inlets on the outside of the hull. The charter company just does not want to fix it. This is not a generator issue if it’s the port AC breaker popping. The Genset breaker would be tripIng if that were the case or the Genset was overloaded.

Which company?

We had this issue once and there was seaweed jammed in the intake on the bottom of the boat. I used a butter knife to dig it out, but it took some effort. I would check the items George mentioned - likely overheating and shutting off due to a lack of water flow. Good luck!

Many times we have had sargassum in the strainers tripping the breakers and have had to go in the below deck hatch and clear the strainers...agree with George and Steve

I remember chartering a Cat, a Lagoon 39 from memory in The Grenadines, I was asking about the AC & the smiling guy said, 'you're in The Caribbean with constant 15kt winds, why do you need AC? '

Boat rented with Gen and AC and should expect it to work. Answer to not run it (or limit of 2 hour a day) is not acceptable... at least without a good faith attempt to generator back in running order.

In regards to being clogged, check strainers and then the thru hull fitting. We have unclogged ours using air pump from dinghy..

Which Company told you not to use the generator/AC?

Nibj - Thanks for sharing the rest of the story that it wasn't just an arbitrary restriction imposed by the charter company.

I think the majority of marine AC units are Dometic Cruisair. Are you getting an error code on the control panel when the unit shuts down?

Common codes are:
- LO / AC (low voltage. Typically overloaded AC generator or poor dockside power)
- HI / PS (high pressure. Typically loss of water flow from clogged strainer or AC pump failure)
- HP / -- (high-pressure switch failed to open or circuit wires open)
- LO / PS (suction pressure too low. Typically loss of gas)
- LO / -- (suction pressure too low. Failed low-pressure switch or circuit wires open)

Prior to the unit shutting down, I would visually confirm that there is a strong, steady stream of seawater coming from the AC outlet. If not, I would go through this order of checks:
- Confirm the thru-hull is open 100%.
- Check for clogged external sea strainer near the bottom of the hull (typically from sargasso or plastic bag).
- Check internal sea strainer for obstructions. You'll need to close the seacock and then open the strainer cover to check the strainer basket.
- If intakes are clear, then there could be air pocket entrapped in the seawater line. You'll need to bleed the air of the system. On my boat, I open the seacock, activate the AC unit so that the pump turns on, carefully loosen the seawater strainer cover to allow some seawater (and air) to squirt out and then tighten the cover.

If you have good flow, then perhaps you have a voltage issue. Have you tried shutting down the opposite hull AC unit to see if this prevents the AC from tripping? On many boats, the generator is minimally sized with little excess capacity to simultaneously power much besides the AC units. Even the start-up currents of other appliances might cause a low voltage trip of an AC unit even if the generator is still able to run. You've presumably already confirmed that no one is using high amperage appliances while the AC is running (such as microwave, blender, portable hairdryers). I was on a charter boat where the AC or generator would routinely trip offline each evening around 5 pm (as the crew were showering). After a couple days, I had two female crewmembers come up from their respective cabins to complain that both their 1500W hairdryers always seemed to stop working at the same time.

Another culprit can be icing of the evaporator coil. This can happen if the unit's cooling operation runs too long on a warm humid day. For example, if the thermostat is set unrealistically low (e.g. 65 deg-F), if cabin hatches and doors are left open, or the AC outlet air vent is blocked (by shoes/bags/linens/etc).

Hopes this helps.

Super helpful information, thanks everyone. I’d prefer not to mention the company (at least until the charter is over). I will check for error codes and sea weed. Do you think that iPhones (6), iPads (5), and computer all charging would make any difference?

I know there are no hair dryers because of complaints in that direction!

The amps those devices draw is not enough to matter.

Look for the boat manual online if you cant find the generator water strainer. As George said start outside at the through fitting first. For the 514PC the strainer is generator side forward cabin floor panel.

Make sure you check both the generator water intake system and strainers but more importantly the port AC water intake and strainer. You stated the port AC breaker is tripping not the generator. It’s possible the generator could be reaching capacity and surging causing the port AC trip so look at both. Charging IPads ect.. is trivial toward total load. You might however consider shutting the battery charger down just before you go to sleep if it can be isolated from the inverter. It does pull a load. I doubt the boat has a watermaker but absolutely shut that down if it does. They are a very high draw item.
On most Gensets you can tell if it’s reaching capacity as you will feel the Genset surge and rumble just a bit.On my boat if this happens it will kick the AC chiller off. To get that load I need all AC units on along with the watermaker and battery charger.

I don't have a dog in this hunt, but am I the only one thinking that, for what a charter costs, you shouldn't have to be doing maintenance? More broadly, I'm wondering if some charter outfits are skimping on maintenance, to the detriment of customers.

Clogged strainers are something that you need to be able to deal with. I have found plastic bags, rags, seaweed, jellyfish ect.. clogging the strainers. I have also found mussels growing in hoses and just plain dirty strainers that obviously were not cleaned on a routine basis. The later would be on the charter company. It’s always a good idea on the boat briefing to have the briefer show you the strainers and check that they are clean.
The OP’s problem could be something he picked up or it could be a maintenance issue that the charter company owns. From his description of the call to the charter company I suspect they are aware of the issue and it might be on them. The AC unit might be old and simply pulling more amps than the spec and the charter company is waiting for some down time to pull it.

Jumping in late. Great topic. We had a similar problem recently. Our chiller would trip off after running for about 10 minutes. Generator was not overloaded (the meter on our electric/control panel can be toggled to show watts to verify generator load). Did all the strainer and intake checks. No go. We were able to limp along putting the chiller in "eco" mode which worked fine as long as we started cooling the boat a couple hours before bed. Back at base after our charter it was found that clams (mussels) had been growing in one of the lines feeding the chiller. Lines replaced. Good as new. Wish I had been privy to George's last post at the time. Had no idea that sea life could get past the strainers and filters, but it makes perfect sense.

Regarding shellfish and other gunk in the AC lines, I doubt any charter company regularly (if ever) runs an acid solution through the AC lines to descale the lines. A great product is Barnacle Buster to clean out AC lines as well as Engine and Generator raw water cooling lines and heat exchanger. Pour it in and let it soak for 12-18 hrs. Amazing the dissolved gunk that comes out. AC efficiency improves and you may see your engine operating temperatures drop a few degrees.

Ah! Didn't know about doing that, BaardJ. Checking with our charter company now. Thanks for the post!

For sure my friend....you would think that and you can usually get them out to help but as a boat owner and tinkerer like to try and keep moving and certain things happen with regularity. I think maintenance is short staffed and boats turn around so quickly there is never a complete lookover. Generator issues are like fleas on a dog


Best to you and the Ratman

It would be great to know what charter company. When we charter a boat with genset and A/C, it is so we can use it every night to get a good night sleep in the cool. If we couldn't do that, we might as well get a boat without a genset for a lower price.