Dufour 35

[Cheechako]

Does it reach rpm as is? maybe not propped correctly?
35 HP should be adequate and has the advantage of being a 2500 rpm engine instead of one of the newer over rated high rpms ones..... "featuring 35 horsepower at 2,500 rpm and a maximum of 2,800 rpm in overspeed mode."

Read more : http://www.ehow.com/list_7672974_volvopenta-md17-specifications.html

[JimSwe]

Hi,
In the spring, right after the launch, it will up to almost 7 knots at 2400 rpm, checked with an external tachometer.
would be interesting to know how fast it was when it was new.
but would like to have a little more power when running against the wind

[roverhi]

That's probably hull speed. Do you want to pull water-skiers?? A more powerful engine is just going to allow you to dig a deeper hole in the water, burn more fuel and possibly pick up a few tenths of a knot in boat speed. Oh yes, there is $10-$15,000 dollars a new engine is going to cost to have installed.

If the engine runs fine, doesn't have any issues with smoking, oil consumption, etc, it's probably fine and you'd be foolish to replace it for short distance cruising and daysailing. If you are going on an extended cruise, then it could be something I'd do.

Originally Posted by JimSwe

Thanx,
Just need to replace the engine.
Anyone know if there is any good choice of engine to replace the old MD17 with, a stronger one would be good becouse the boat only make 6,5 knots on full throttle,

[JimSwe]

waterskiing yes of course.

no engine is old and consume oil, no have no intentions to run faster, just have more power and reliable engine. Nice to have in headwind in narrow passages in the archipelago when there is no room to sail. So I wonder if there is anyone who knows a good replacement engine.
// Jim

[a64pilot]

There are several engines, don't know of a drop in replacement.
A consideration I would take, is to make sure the engine is common for where I would cruise as parts are available. I wouldn't purchase an engine that is not still being manufactured

[roverhi]

Like those old Volvos but it's probably salt water cooled so will have some corrosion issues as well as wear. You can rebuild that engine to as good as new if there are still parts available. IIRC, the parts that are in contact with salt water are pretty much all replaced in a rebuild. That will be the cheapest way to go. You won't have the dollars that go into problems with relocating engine mounts, wiring, exhaust, etc that make putting in a different engine tres cher.

An engine with more than 35 hp isn't going to get you much, if any, improvement in performance. The theoretical hull speed is 7.1 knots under ideal no wind/wave conditions and going with more hp is just going to dig a deeper hole in the water. But then I've got 27hp in about the same displacement and think it's just fine. For a replacement engine would look at the usual suspects, Yanmar, Beta, etc. These newer engines will be faster rpm for the same hp but will undoubtedly be a hundred or more pounds lighter. A lot of people like the Beta because they are based on Kubota tractor engines so non marine parts can be sourced at at your local tractor dealer world wide. Same is probably true for Yanmar though you have to go to a John Deere shop to get parts for them in the US.

[barnakiel]

MD 17 had (?) 30+ hp except for one. At 6.3 t displacement you do not need this much. You are at 5 hp/t. With 3 hp/t and a far less efficient hull we entered atolls in the Pacific. If you are in Sweden, you do not have tidal currents and other such likes to worry about.

You will find countless decent engines to replace yours: VP, Yanmar, Vetus, Nanni, Beta, Bukh, etc.

6.5 at full throttle is OK with this LWL. Clean the bottom, clean the prop, then make sure the prop is well matched with the engine and the boat.

b.

[JimSwe]

thanks
no engine is fresh water cooled, but I do not know how long it has been there.
yes they are what I'm looking mainly because you can buy a new overhauled md 17 for $ 3,000 if you leave your old one in exchange.
But it's just that if it blows very much headwind, it is hard to get forward. from my home port, I have many narrow passages before coming out on the open water. but perhaps it is like that witht sailboats, maybe not meant to use the engine when it is blowing 15 m/s headwind

[Robin3]

Originally Posted by JimSwe

Thanx,
Just need to replace the engine.
Anyone know if there is any good choice of engine to replace the old MD17 with, a stronger one would be good becouse the boat only make 6,5 knots on full throttle,

The original engine should give hull speed if the prop is correctly sized and pitched, it was I believe a Volvo badged green painted version of the Mercedes OM636 4 cylinder. Our friends replaced the one in their Dufour 35 with a Yanmar, not sure which size, possibly a 4JHE 44hp 4 cylinder or similar, but they chose it as they were working for the Moorings company in the Caribbean at the time and got it through them at a discount, so there might be better options. I had a Mercedes OM 636 in a previous boat ( westerly 33 ketch) and replaced it with a 4 cylinder Volvo MD22L (a Volvo badged, green painted Perkins Prima 50hp). The OM636 was not a marinised Mercedes road engine but was a marinised generator (stationary0 engine dating back originally to pre WW2 and was the type once used IIRC at a base camp in the Arctic. The marine versions were not German made but built in Spain under license.

[roverhi]

Try motorsailing. You can point up to 30 degrees off the wind with the engine turning moderate rpm and probably make 5k easy through the water. My old boat, a Westsail 32, 20,000# plus displacement with an MD2 Volvo of something less than 25hp. We motorsailer the few times we had to power into a significant headwind. In light wind conditions would easily power at 5k without pushing the engine.

If you can get a drop in rebuilt MD17 for $3,000 plus a core engine, I'd be on it in a second. You are going to spend 4-5 times for a new engine by the time you get it installed. l

FWIW, delivered a W32 with the then MD3 engine, the earlier version of the MD17 will less hp. It was plenty of power for that boat.

[Sailing Soon]

Anyone on the boards have any experience in blue water with a Dufour 35? I've followed NAMANI's travels and they seemed to have had very little trouble sailing across the Atlantic and Pacific in one.

[Cheechako]

Friends of mine we met cruising rounded the world in 7 years in a 34 or 35... cant remember which. How old? Theirs was an older one.... and they really liked it.

[boatman61]

Great sea boats and comfortable live aboards..