Houseboat propulsion

[Waterrat]

I am designing a 14 by 46 ft. houseboat (20,000 lbs. gross weight) and am looking for input on selecting a powerplant for it.
A friend of mine who has been building houseboats for over 20 years has switched from installing 3.0 ltr. inboard/outboards to smaller (60 hp) 4-stroke outboards with high thrust props on them. He has built a 16 by 68 footer and has two 60 hp engines on it. He is sure that my 14 by 46 footer will be happy with 0ne 60 hp on it.
Does anyone have any experience with this size of engine on a houseboat of this size?
The most obvious plus is the reduced fuel consumption. But a big minus is the small capacity alternater for charging up the batteries.
The boat will be used on an inland fresh water lake (Lake of the Woods).

any comments?

[Deering]

Depends how fast and far you want to run it, but I'd agree with your friend. Another advantage is ease of servicing an outboard. I'd suggest separating the propulsion and charging decisions.

Take electrical consumption into account when outfitting your boat - buy more efficient appliances/lights. With a houseboat that large you should have ample roof space for solar panels. A small auxiliary generator would complete the package.

[cyclops]

GO directly to REAL engines. 2, gas or Diesels. You have a full sized SUPER wind sensitive shape. Out boards are a waste in, torque, HP with a full load of people, high wind, COST. They do not like high rpm's continously. Maintanance is very high in continous duty. Parts are outrageous in $$. Selection of props is next to nothing. If they were so good, they woud be on passenger ships and freighters.

[D'ARTOIS]

Act Acta.....Outboards are totally useless in this case except you don't go further than the boundaries of your pond.
Further comments I leave to the other memebers.....

[Deering]

Someone oughta tell these guys: http://www.catamarancruiser.com/Vagabond%2035'%20and%2043'/vagabond_14_x_50.htm

Or these guys: http://www.bahamahouseboats.com/

[cyclops]

They are presumably trying to make as much profit as they can by under powering everything? They cruise by in their boat with a little bigger engine? If you do not come back from a squall? Piece of paper and you are history. NEXT houseboater.

[cyclops]

They are presumably trying to make as much profit as they can by under powering everything? They cruise by in their boat with a little bigger engine? If you do not come back from a squall? Piece of paper and you are history. NEXT houseboater. It is a huge slab and hull of wind resistence for the motor to buck 30 to 40 mph winds. I think it would go backwards.

[Willallison]

What absolute clap-trap!
Outboards works perfectly acceptably on houseboats the world over - nobody's suggesting that you try to cross an ocean in one of these things. We regularly use a 15hp outboard with a high-thrust prop on our tender as a 'tug' for our 48 foot boat ( which weighs more than double your 20000 lbs) - it has plenty of thrust.
So long as you size the powerplant such that it isn't running flat out the whole time, fuel consumption and engine wear shouldn't be much of an issue. Even if you throw the thing away after 1000 hrs, you'd get at least 10yrs service as a regular pleasure user.
Personally though, I'd go for a pair of smaller units rather than one big one - not because you need the power, but to aid with manouverability - particularly with all the windage that comes with a houseboat..

[marshmat]

Lake of the Woods doesn't see much in the way of severe weather. Most of the houseboats I know of there are outboard powered. For something the size of what you're looking at, I'd suggest if you want outboard, go for two 35s or 40s. You'll thank yourself for choosing small twins over a big single when you try to dock the thing. Go a little larger than you think you need, the weight isn't an issue but a pair of 40s at 75% throttle will last a lot longer than a 60 at wide-open. Much quieter too. But if noise is a big concern, go inboard.

[safewalrus]

Now lets get the definition right - a housboat is a 'box on water' in which peole live right? It's primarily designed for that right? It is occasionally taken along to a new area 'cos your p***ed off with the neighbours or several other items! You proably own a runabout for 'normal' use, right? So the main thing is lots of room in the house but occasional running use at not to great a speed? a runabout that goes like s*** of a shovel to get to market or the pub or whatever? Both need engines? why not the same ones? three identical outboards with a small crane on the 'box' you get the best of both worlds and a spare for maintenance, seems sensible to me! Am I missing something? (I'm sure some smartass will tell me - bet he's american! [USofA] not the rest)!

[Deering]

Well Walrus, you're right, I am an American... but not sure why that matters in this forum.

It turns out that I pretty much agree with you. The outboard used for the runabout might have the same power head as the houseboat, but probably different lower units. A runabout travels at say 25 knots and weighs maybe 1,000 lbs (450 kgs for you non-Americans) while a houseboat travels at say 6 knots and weighs 20,000 lbs. Most outboard manufacturers make a "high thrust" version of their units specifically to be used for pushing large boats - the lower unit has a larger gear reduction and a larger prop. Works fine on the houseboat, but not optimal for the runabout, and vice versa.

[marshmat]

May I suggest either a pair of Honda BF40s or a pair of Mercury 4-stroke 40 BigFoot motors? Seems these two are among the most common on low-speed houseboats, at least from what I've seen. Amazing how quiet the Honda is.... would be well suited to walrus's engine-swapping idea too. On that note, why not combine them- have the runabout dock into the back of the houseboat, much like the late-90s ShuttleCraft PWC/runabout?

[cyclops]

I saw a Pontoon Boat that was a pleasure to watch. Chevy V8, 4 seconds on plane and out of sight, fast. Quiet and no outboard smell. I could move around on that one.

[ColCampey]

What about going electric - Couple 20-30 hp motors powered by a battery bank charged up by Diesel generator. Small electric bowthruster to deal with windage problems, heaps of electric energy for appliances from decent size battery bank, solar panels to add to generator output, less maintenance.
Electric motors give full torque as soon as they start turning.
The generator only runs at its most efficient speed so less fuel used, especially if efficient electric motors are used.
Check out <http://www.feys.org/>.
Good luck,
Col Campey

[PAR]

Currently I have two healthy sized houseboat designs (both in service and over 50') and each is powered by outboards. Sure there are more efficient propulsion units, but why. Outboard reliability and reparability make them an easy choice when limited range, use and protected waters are the norm.

Electric upgrades are pretty easy to employ. Your friend is correct, Waterrat, though on a craft that size you'll want the redundancy of twin outboards, plus the maneuverability benefits (think hard about a bow thruster). You'll get an extra alternator in the deal too.