how slow do we go

On my way south from the chesapeake 2 years ago I was docked at conjock NC for the night Thanksgiving eve . The next day I arose before daybreak to get an early start .I found the fog so thick I could not see the far end of the dock. Still I was underway at daybreak racing high winds to cross the Albemarle sound. Those that have been there know how rough it can be and with winds over 35mph the bridge over the alligator river will not swing. On my way out I came across 2 very large sport fish (55-60') on their way back to the dock. A call on the radio confirms , the fog only gets worse away from the dock. Still I continue, after all, I have radar . So I do make it fine across the sound never seeing the one marker midway. Although I can not see the swing bridge I mange to make the alligator river with out hitting the bridge or going aground in the tricky entrance to the river. Anyway the fog lifts a little and I have a good day. The next day all was fine and I make good time as well. At about 1 the next afternoon I was passed by the same two large sport fish boats I saw returning to the dock two and a half days ago. I called on the radio to say hi and ask when did you guys finally get off the dock? The answer 6am this morning Another voice i did not know comes over the radio saying" Dam I need a faster boat" . And I realize my little marine trader is really slow and those big sportfish are fast. But still I did make south florida after 21 day and a little over 400 gallons later. I do wonder how much fuel the two big sport fish boats used

Greetings,
I would guess anywhere between 50 and 120gph. So in 2 1/2, say, 8 hour days....between 1000 and 2400 gallons. 21 days sounds fine to me.

During the past many decades I have come across many large SF owners - they clearly understand their fuel burn and cost. For a good read go to Yacht Forums and read Liberty's postings about a 52' Hatt he bought in the US and just finished moving to Australia. "Speed" can be fun - sometimes 25 knots in a big SF in 8' seas is a lot more comfortable than putting along at 7 knots.

Then there are the less traditional boats. I'm burning about 4-5 gal/hr at 14-15 knots in my 34 ft. PDQ power cat. When I passed a Nordic Tug 42 on the ICW yesterday he said he was burning 7-8 gal/hr and he was probably going about 8 knots. If I were to cruise at 8 knots I'd burn about 1.5 gal/hr.

dvd

6.15 knots most all the time.

6.3 knots (1800 out of 2400 RPM) most of the time after engine warm-up. Can go (and do sometimes) a knot faster but with over twice the fuel consumption.

dvd said:

Then there are the less traditional boats. I'm burning about 4-5 gal/hr at 14-15 knots in my 34 ft. PDQ power cat. When I passed a Nordic Tug 42 on the ICW yesterday he said he was burning 7-8 gal/hr and he was probably going about 8 knots. If I were to cruise at 8 knots I'd burn about 1.5 gal/hr.

dvd

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Did I see you going tru hollywood this week?

7.5 knots seems to be our sweet spot with the re-fit Yanmar. DVD....no fair to compare the PDQ 34. If I didn't bash myself so badly on my only overnight stay (thanks to Dick Tuschick), we'd have one. That is one efficient pair of hulls.

I do understand and have enjoyed the speed . It is a matter of economics for me. The fuel bill for that sport fish represents my complete budget for the winter. It is either go slow or dont go for me. This is my 5th year on boat and this winter I did not go home at all

For me and my lifestyle....while fuel burn is important enough...I just say to myself...50 miles a day...where's the next fun place between 40-60 miles and that's where we are going.

Unless you have to be someplace....I can live with where ever I wind up each day. But that's semi-retired for you...it now is the journey as much as the destination.

<<Did I see you going tru hollywood this week?>>


Not me -- I'm on my way south but haven't gotten that far yet.

dvd

dvd said:

Then there are the less traditional boats. I'm burning about 4-5 gal/hr at 14-15 knots in my 34 ft. PDQ power cat. When I passed a Nordic Tug 42 on the ICW yesterday he said he was burning 7-8 gal/hr and he was probably going about 8 knots. If I were to cruise at 8 knots I'd burn about 1.5 gal/hr.

dvd

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DVD, How about posting some pics of your new PowerCat? I've long been intrigued by the efficiency and comfort of the large powercats. Great cruiser. How is your fishing/dingy access? Accomodations....2 staterooms/2 heads? No way for us trawlers to compete with your speed and efficiency.

FlyWright -

We've got reasonable internet connection here, so I took a few pics this AM. Take into consideration we are in "travel mode" and have been traveling hard for the past week and a half. Dinghy/water/fishing/dock access is great with steps built into the pontoons. I've got 2 "staterooms" which are really "bunk rooms" with queen size berths, but no standing headroom once you crawl onto the berth. The berth access was the only compromise in this boat, but everything else is worth it. Single head with large separate shower. Full galley with refer/freezer, stove top and oven. Large central dinette in the main salon with another seating area (referred to as the "piano bar") across from the lower helm. There's a large flybridge and upper helm. There are a few PDQs on Yachtworld with plenty of pics. The interior was changed considerably from 2005 on.

I've got twin 75hp Yanmars - it also came with 100hp twins as well.

dvd

6-6.5 knots most of the time, 1.3-1.5 gph.

17-18 knots some of the time, 10 gph.

Greetings,
I've heard it said that outboards use about 1gph per 10 HP at "full" throttle as a general rule of thumb.

dvd
love that boat

RT,
Sure but are they more or less efficient at 1/2 throttle?

Thanks for the pix, dvd. What a great cruiser!! Safe travels.

RT Firefly said:

Greetings,
I've heard it said that outboards use about 1gph per 10 HP at "full" throttle as a general rule of thumb.

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Is that for two or four cycle? We have a 90 hp Yamaha 2-cycle on our Arima and at 5,000 rpm which is close to but not full throttle it burns about five gallons per hour. Which gets us 30 mph.

The 30mph is meaningless but the 5gph is spot on it seems. But even though you're running 5000rpm it must be lightly loaded. I run my outboards about 1000rpm less.

RT Firefly said:

Greetings,
I've heard it said that outboards use about 1gph per 10 HP at "full" throttle as a general rule of thumb.

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That's the way it used to be "guessed'"....not sure after the 90's it remained all that accurate as outboards evolved quite a bit. But for 80s/90s motors...that was pretty accurate but hard to determine as not many like to run their larger outboards at full throttle long enough to get a good guestimate.

Greetings,
Yup, my anecdotal "guesstimate" WAS based on 80s/90s technology and served to give one a rough idea of fuel usage/range. One could "assume" mileage would be better at lower throttle settings.

Its the fact that its a GASOLINE fueled engine that creates the 10hp/gal .

The most modern direct injection (just like a diesel) GAS engine is up to about 13 hp /gal.

This comes with expen$ive maint and a computer controled everything.

Fuel , ignition, valve timing , all from the brain box.

Big advantage for a boater is light loads extend engine life.

Unlike a diesel.

I have had a long history of owning gas powered boat both sterndrive and outboad but living with diesels for 5 years I would not consider anything but diesels now

Mine is a slow boat from China.

"Angelina" has two speeds: slow and stopped.

All this talk about mpg or gph makes me sad. A trip up/down the ICW, or anywhere else aboard is priceless.

jeffnick said:

All this talk about mpg or gph makes me sad. A trip up/down the ICW, or anywhere else aboard is priceless.

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Oh, there's a price alright, my cruise in May cost about $1K in fuel plus some marina fees and meals, etc. But, that's well worth it for a 31 day vacation. Pretty hard to beat, I think. A lifetime of memories for two.

Slowing down not only saves fuel for most of us, but you get to see the sights along the way. If you're in a rush, drive or fly.

So my normal cruising speed is whatever 2,000 RPM gets me. It's 7 knots over water. On the AICW, that could be anywhere from 5 to 9 knots over land.

I'm thinking about a two month cruise next summer.

I understand fuel cost do not seem like a big deal, but any of us on a shoe string budget cruising full time can tell you, all cost must be kept as low as possible or we may have to tie to the dock and god forbid get a , , a a JOB

We generally cruise at about 7 to 7.5 knots, at 1650 to 1700 or so RPM.... I've found that to be the "sweet spot"...and she gets good fuel efficiency.....

Cruising along at that speed lets us see more and have a more relaxing day...... like these little critters: A momma otter and two pups.... on the Caloosahatchie not far from the big lake.