Question About Power Cats

I just got back after two weeks on a Lagoon 40 S2. The winds were so light we pretty much motor sailed everywhere we went, including Anegada, and our fuel bill was less than $150. We covered 184 nautical miles.

I am wondering what the fuel bill is for those of you who charter a power cat. I like their set up and, as much as I enjoy sailing, will probably go that direction next time. Thanks in advance.

We did a 10 day trip on a Moorings 474 powercat. Fuel including generator use was just over $300 from what I remember. (You could search my past posts for a more accurate number). If you run the cat at a modest speed (we did 8-9 knots) it won't burn that much fuel at all. Considering that the distances in the BVI are quite short there's no real need to go roaring around at 20 knots even if the boat is capable of it. And a couple of benefits to the power cat include a much higher and larger flybridge (everyone will want to be up there trust me) and the lack of rigging for the sail. This makes the front deck more usable and mooring a lot easier. Our trip was your typical BVI loop including a visit to Anegada.

We were $315.17 for 110 gallons in a Moorings 433PC last June, 7 day trip including generator with AC use.

Where was fuel $3.00 a gallon, seems very inexpensive

$2.86 at the Moorings June 25, 2016.

The below is an excerpt from something I wrote last July. The boat was a Moorings 433 PC.

"The boat was great. We burned 70 gallons of gas making a modified clockwise loop of: Norman, Jost, Scrub, Cooper, Saba rock, Lerverick, Peter, RT. $198.50. We ran about 33%-40% throttle for the most part and probably averaged about 8.5 knots. Also ran the gen each night from about happy hour through breakfast the next day. Fantastic economy in my opinion."

I own a pc 433 and last trip in Jan 17 was 125 gallons for 9 days, 184 NM and generator 8 - 10 hours a day. 3.38 for Diesel. I cruise 12-14 KTs, usually on autopilot, and can cover some ground. Point and go.

I have rented in the past the 474 and the PC51 and based on an average BVI trip and reasonable usage of the generator and moderate cruise speeds you can figure between 10- 15 gallons per day. Fuel prices have been from high 5.00 to as low as 2.75 so best to focus on gallons. The generator will surprise you at how much it burns. .5 to .75 GPH. Boat engines are not bad if you take it easy. New Yanmars are really nice and quiet.

I'm curious if power cat operators typically run one or two engines while underway. The potential fuel savings running one engine could be substantial on the larger power cats with 150+ hp engines.

On my Saba 50 catamaran with twin 75 hp engines, running both engines obviously doubles the fuel burn but with only 0.8 kt increase in speed (equivalent to a 10 minute time savings motoring to Anegada from North Sound). I prefer to run one engine to minimize overall engine hours, fuel consumption, and especially noise and vibration in the cockpit. It requires only a few degrees of rudder angle to compensate for the offset thrust.

Diesel price at Crown Bay Marina in St Thomas was $3.17 last week, $3.18 this past December, $3.21 in November, $2.60 in June, and $2.75 last March. Looks to be about $0.20 cheaper than BVI prices.

Keep in mind that fuel flow is load not rpm dependent. If you are running both motors at a given rpm there will be less load and lower fuel flow then just one motor on a per engine basis. I experimented quite a bit with a voyage 440 cat on one verses two motors. In the end I found that if you ran two motors at the same cruising speed as one motor the difference in fuel burn was about 20%. The big savings comes from slowing down.
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From a fuel burn rate there is a cross point at which 2 engines are more efficient than one as pointed out above. In a PC you would have to be going prob. less than 1000 rpms on one engine, which is a bout 4-5 knots to make it more efficient. Moorings used to deliver the PC this way some 6000 miles and many days and alternating engines. Now they ship them on a freighter and drop them off in Sir Francis Drake channel.

As for my use I always run 2 engines as I like the added maneuverability it gives me as well as the speed. Also it evens the hours out on each engine and creates hot water for both hull cabins. Given my crusiing speed, one engine would be too much strain and pull, not even sure one would get that high of speed. I have some performance graphs on my boat that I can share. The Moorings(R&C builders) have them on the most all of their PCs, especially the newer ones

You're correct George. For me to regain the 0.8 kt speed difference running with just one engine, I have to raise it by ~300 RPM which lowers my net fuel savings from 100% to 25%~50% depending on the reference cruising speed/RPM (more savings at lower speed/RPM).

Does anyone have any experience or opinion of the Marine Max 484 vs Moorings 514PC?

CaptSharky, there may be others that have bareboated one or both that can share first-hand thoughts. We looked hard at both as ended up booking the 514 for our upcoming trip. I can share our logic, if it helps your thought process. I'm sure you'd have a great time aboard either. The 484 has a watermaker and free wi-fi, but those are nice-to-haves for us. The 514 is a little longer LOA with an extra foot of beam and layout that has a little more outside (vs. inside) space. Even with additional discounts from MarineMax, the 514 ended up being about $1,000 less expensive. In the end, the 514 seems to be more boat for less money. Hope that helps some.

The hydraulic swim platform on the 514 is fantastic if you dive or just a place to hangout on the water.
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