Has anyone ever put outboards on the back of their houseboat? We are thinking about adding two Yamaha 70 with a platform to our 1981 Holiday Mansion. They should give us better gas mileage and a quieter ride. Any thoughts on doing this?

Pam

What makes you think outboards would be better on fuel? You would need four stroke outboards to be more fuel efficient. A two stroke's lower torque would mean that you need to push them much harder to get the same speed. Outboards are high speed, high HP, low torque engines that work very well on light weight boats.

You would also destroy the resale value of the boat. Its far cheaper to recondition what was installed originally than convert.

I guess you all don't like our idea. I really appreciate your replies, though - it gives us food for thought.

We were definitely thinking 4-stroke engines. Having two would give us better handling - of course, our other option would be to put in a second engine matching the one that is there now.

Resale value shouldn't be a problem - the boat is already 20+ years and we plan on keeping it for a long time. I think by the time we get around to selling it there won't be much value left in the old girl.

Thanks for the help - if you think of any other pros or cons we would love to hear them.

Pam

Pam:

I bought a 1973 SeaCrest (Marinette) aluminum houseboat 1 1/2 years ago, and sailed it 843 miles from Lake Barkley, Kentucky to my home port in Trempealeau, WI, which is on the upper Mississippi River. It had twin inboard 80 HP Ford diesels with V-drives that were about shot by the end of the trip.

Contrary to the advice I was given on several marine forums, I removed the diesels, fabricated a couple of aluminum transom boxes, and mounted two new four stroke 90 HP Honda outboards on the boat. Some people at the Tremp. marina said I was crazy by doing such a thing, but now my boat is viewed by many with envy. Some say it looks like it was originally designed to be fitted with outboards.

Here's some info you may find helpful in making your decision:

Fuel Economy: At a leisure cruising speed (both engines 1/3 throttle, 2000 RPM), I get about two miles per gallon. At wide open throttle (6000 RPM) I get considerably less.

Max. Speed (GPS): I was able to get about nine MPH with the diesels. I can get 16 MPH with the Hondas.

Maintenance: With the inboards, I had to virtually stand on my hands to check fluid levels. Changing oil/fuel filters, impellers, belts, etc. required removal of an interior bulkhead and me "wriggling" like a snake into the engine compartment. Winterizing my Hondas last season after pull-out was a breeze. While standing on the pavement, I simply popped off the shrouds, drained the carburators, changed the engine oil and filters, and the gearcase lube. Two engines - two hours. Spring commissioning required that I squeeze the in line hose bulbs to get gas into the carburators. Two engines - two minutes. Maintenance on my diesel genset is also much easier since I removed the inboards. In fact, there's so much room in my engine compartment now, I can dance cheek to cheek with the Admiral on either side of the genny.

Handling: If you decide to go with outboards, mount them as far apart as possible. I did this, and with the new hydraulic steering, the boat handles great in tight quarters, as well as on open seas.

Trim: Definitely go with power trim. This makes it a quick and simple chore to inspect the propellers for damage, ski rope, fishing line, etc, versus hiring a diver or pulling the boat. I also tilt my engines out of the water when I'm away from the boat to keep the slime build-up and the zebra mussels away.

Sound: The inboard diesels w/ V-drives were loud and shook the entire boat. If it were not for my new tachometers, the Hondas are so quiet that I have to go look at their water pump indicators to see if they're running when at idle.

Safety: All gasoline combustion occurs outside of the boat with outboards.

By the way, most of the rental houseboats in this neck of the woods are equipped with twin outboard engines.

Cap'n Jeff -

You have made our day! We stopped by a local marina that also does repair work and talked with them about putting outboards on the back. They said it sounded interesting, which at least didn't shoot us in the foot. Then we got in the lake yesterday and checked out the bottom of our boat for barnicles and sludge, and the worst buildup is on the outdrive. How nice it would be to be able to pull the props up out of the water!

We were also looking at the space we would acquire without that big engine - we wouldn't have enough room to do a jig, but all my husbands tools could go down there and be out of the way and there would still be room to spare!

You said your boat was aluminum, but I guess this would work just as well on a fiberglass hull. And since we aren't speed demons, we are looking at Suziki 70s. The tip about setting them as far apart as possible is very welcome - I don't think we had thought of that.

Again, thank you for taking the time to respond - this group is great!!!

Poorbuthappy1

Pam,

If you would like to see some pictures of the project, send me an e-mail at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Cap'n Jeff

I wish you a lot of luck. I still think it is a big waste. You have the cost of the engines, fabrication of the bracket costs as well as control units. In the end you will have a slow boat that is no better on fuel with a much lower resale value and lower appeal for resale. If you want a boat with outboards sell the HM and buy one designed for them. Of course as Cap'n Jeff suggested it can be done the question is why? Are your current engines in need of replacement?woodboat38145.5216782407