Best Engine / Fuel Economy for a 27-35' Sailboat in the Inside Passage

[bdurham]

planning a trip up the inside passage. we'll be doing a lot of motoring, and we will sail whenever possible. trying to find the best combination of boat and engine.
would we be better off having an internal diesel engine, a small outboard engine( or maybe even two small outboards)?

we are looking for high reliability, and low cost.

we don't need to travel at much more than 5 knots.


would love to hear some ideas.

[Vasco]

diesel

[mbianka]

Originally Posted by bdurham

planning a trip up the inside passage. we'll be doing a lot of motoring, and we will sail whenever possible. trying to find the best combination of boat and engine.
would we be better off having an internal diesel engine, a small outboard engine( or maybe even two small outboards)?

we are looking for high reliability, and low cost.
we don't need to travel at much more than 5 knots.
would love to hear some ideas.

Have you thought about electric propulsion? I converted my thirty foot sailboat to in 2008 when my diesel died and have never looked back:
THE BIANKA LOG BLOG: Going electric: Part 1: The why and how
I find it much quieter and less fatiguing to motor with it than when I had my diesel both above and below deck. Saved hundreds of dollars in maintenace costs too! If you find the boat you want with a dead diesel it might a way to go.

[twistedtree]

The greatest efficiency will come from a diesel, and the slower you go the better mileage you will get.

[ozskipper]

outboards are ok up to say 24-25 ft. After that, for long distance cruising, deisel!!! Just diesel. Diesel will aslo provide good charging for house batteries.

[Chief Engineer]

Have you chosen a boat type....yet?

[Boracay]

Assuming from your question you haven't brought the boat yet and are looking at two similar boats, one with a small outboard, of, say 5hp, on a bracket off the back and one with a small diesel engine of, say, 20hp.

Its doable. I see racing boats of similar size with 2.2hp outboards and noone bats an eyelid.

Its important to note that there would be many more important buying criteria than engine type.

However, restricting my reply to the literal wording of your question the 5hp outboard powered boat would most likely be cheaper than the diesel in terms of direct short and long term operating costs. A much bigger outboard may have costs similar to a diesel engine.

A late model outboard from a reputable maker should be very reliable.

Most boats would not have the hours of use to justify a diesel engine on cost alone.

There are other than monetary costs however. A small outboard may suffice under perfect conditions, or even under most of the conditions that you are likely to encounter, but for those times you meet rough choppy conditions with a bit of wind and current the small outboard with the prop coming out of the water frequently could make you wish you had a good sized diesel chugging away.

I doubt if one could average 5 knots with a small outboard, though under perfect conditions it may be possible.

I'll concede that a well designed catamaran with matching outboards under those condition may do just fine.

[bdurham]

Originally Posted by Chief Engineer

Have you chosen a boat type....yet?

maybe a Cal 29, or a tartan 30? we've also looked a bit smaller.

[MarkSF]

Originally Posted by bdurham

planning a trip up the inside passage. we'll be doing a lot of motoring, and we will sail whenever possible. trying to find the best combination of boat and engine.
would we be better off having an internal diesel engine, a small outboard engine( or maybe even two small outboards)?

we are looking for high reliability, and low cost.

we don't need to travel at much more than 5 knots.


would love to hear some ideas.

An internal diesel will have the highest efficiency, and the newer the better. In second place, a new 4-stroke 3 star EPA certified outboard.

The diesels get more efficient over the years. My Universal 5424 uses considerably more fuel than the modern equivalent.

Tankage is an issue to take into account. Carrying large quantities of gasoline for an outboard becomes a safety issue.

[Jesse]

The Inside Passage is not a good place to be low on power when the spring tides are running. The currents there deserve a great deal of respect. I have cruised there with both diesel and outboard and definately prefer diesel, and one with enough oomph to get you through the scary stuff.

[bdurham]

Originally Posted by Jesse

The Inside Passage is not a good place to be low on power when the spring tides are running. The currents there deserve a great deal of respect. I have cruised there with both diesel and outboard and definately prefer diesel, and one with enough oomph to get you through the scary stuff.

what would you consider is enough umph for a 27 to 30 foot monohull if you were using an outboard?

[NewMoon]

FWIW,

Our 11,000 lb 26-foot power boat has a Yamaha 9.9 hp high-thrust kicker, and we max at about 4 knots on the kicker. It's great for salmon trolling and backup, but I sure wouldn't want to be limited to that sort of speed traveling the Inside Passage, as you are often dealing with a 2-knot current, even in some of the big channels. In narrower passages, current can often get to 3-4 knots, and sometimes quite a bit more.

High-thrust (lower gearing, wider flatter-pitched prop) works well if you are going to be going only slow, not at planing speeds. Yamaha makes a 25 hp high-thrust - maybe that could work for your sailboat.

[Selene]

Originally Posted by bdurham

planning a trip up the inside passage. we'll be doing a lot of motoring, and we will sail whenever possible. trying to find the best combination of boat and engine.
would we be better off having an internal diesel engine, a small outboard engine( or maybe even two small outboards)?

With doing a lot of motoring, I am tempted to recommend an inboard diesel. My 31' motorsailor has a 40hp. I do 6kts/hour at 2000rpm using 0.46gal/hour. In addition I get charging on my batteries, warm air and hot warter from the heatexchange cooleant. Do not know if you can get that from outboards?

[roverhi]

A diesel that will get you 6k or close to hull speed in calm water is sufficient. You are primarily talking about powering in no wind conditions on the inside passage and the Sound. The extra horsepower to push into a 40 knot wind and chop aren't the reasons for motoring, most of the time, in this area. For a 30' boat, a 20hp diesel should be more than adequate and give you excellent fuel economy at around 5k. The Tartan/Yankee 30 are excellent boats, btw.

I wouldn't even consider an outboard powered boat unless it's 25' or less. In the summertime, it's probably going to be 70% of the time powering over fairly long passages. Not ideal conditions for an outboard and definitely not the best fuel consumption.

We've always been happy with a 5k cruise speed under power. Should you get into the few restricted passages where currents run exceptionally strong with a foul current, there is always the anchor. If keeping a strict schedule and fighting strong currents are your thing, it's Bayliner time.

[NewMoon]

Originally Posted by Selene

With doing a lot of motoring, I am tempted to recommend an inboard diesel. My 31' motorsailor has a 40hp. I do 6kts/hour at 2000rpm using 0.46gal/hour. In addition I get charging on my batteries, warm air and hot warter from the heatexchange cooleant. Do not know if you can get that from outboards?

I'd agree - we chose an I/O diesel for our power cruiser, in part for the convenience of plenty of cabin heat, hot water, and electric power generation. It's possible to have these in an outboard-powered boat, but for heat and hot water you'd need a separate diesel/kerosene heater like Webasto or Espar. Or, a generator and electric heater and hot water - not very efficient use of fuel.

We began cruising the Inside Passage in an outboard-powered C-Dory 22. It worked quite well, but certainly lacked many of the creature comforts our diesel boat provides.

If I were choosing a trailerable cruiser for the Inside Passage again today, I might well pick an inboard diesel cruiser like a Ranger 25, 27, or 29.