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looking at a 35 nauset(old 35 bruno) as a possible repower project. boat is presently powered by 340 merc(gas).would like to replace with some thing that will give me 18-20 kts cruise, while fairly conservative on fuel. looking for some input from someone who's been down this road that can give me a good idea what i'm in for dollar-wise, so I can make an educated offer on the boat. any help would be appreciated.thanks
I can't give you all the detail's, but a buddy I see every now and then does some moonlighting Desiel repair on some of the charter fleet around Orange Beach,Al.
He told me in 2004 there were aprox 13 motor swap's done in the area and all went with John Deere's. He said when it came time to do the wiring it's all plug and play. I can attest to that with the couple of JD tractor's that I owned. If you bought an optional light all you had to do was plug it into the master harness and bolt it on.
First question is how much hp do you have now and what sort of speed does it make now? That will help in determining how much hp you will need to make your desired cruise. Do you know the Loaded Weight of the Vessel?
John Deeres seem like good engines, though I don't have much personal experience with them. They are heavier than some of the other available engines though.
If you are converting from gas to diesel, you will probably have to change the shafts, and possibly the struts if they won't accomadate the larger shafts. Will also want to determine up front the largest diameter prop you can get under the boat so that you can be sure to match the gear ratio up front. If the wheel gets larger than what you have now you will probably have to also put on a larger rudder.
You will have to either add a return line to the tank or install new fuel tanks (recommended). Are tanks fiberglass or aluminum?
I would take the prices you are being given for the engine and transmission and double it. That will get you into the ballpark for rough estimation purposes. Depending on all the factors mentioned above and how much you do yourself, the price may go up or down considerably.
__________________ Michael Dunlavy
Saunders Yachtworks
-----
24 Topaz, 15' Stauter
I repowered my luhrs labor was about 25% of the total cost engines and extra the balance (2 motors here) tanks did not get changed neither did struts, or rudders. one thing I will say is without a doubt check the size wheel you can fit!!!! If it is a big enough wheel or you don't mind a nice four blade get a 2:1 tranny instead of the 1.5:1 I made that mistake and regret it. Because of all the real world physics that go into spinning a prop in a slippery liquid like water, there is a lot more to it than rpm*gear*pitch*XYZ / ABC.... you get the picture. Spin a big one slowly is my new modo.
__________________ live like the fish are biting 32 luhrs conv. new yanmar diesels
I think in a boat that size you could go with a Yanmar 315 which is finding its way even into
some Maine lobster boats, including mine, and get the kind of speed you are looking for at
a fuel burn of about 8-10 gallons per hour. The Yanmars rev higher than Cummins or Deere,
but are lighter, quieter, and in my experience, more reliable.
Don't think the Yanmar 315 will give 18-20kt cruise. My Cummins 315hp struggles to give my 32 18kts WOT. The 370hp Cummins powered 32+2s get an 18kt cruise. The Nauset/Bruno is not a light boat. Got a friend rebuilding a Bruno. Don't know what is going into it. Used to be a twin & had a hard time getting out of it's own way.
I have recently heard that YANMAR DIESEL has decided not to comply with the TIER 2 requirements in the US and will not build TIER 2 diesels. They will continue to build for European markets only. Has anyone else heard the same information?
I agree with the others as far power required for that speed in a 35' downeast. I would think you would need at least 400 HP for a legitimate 18-20 knot cruise but I'm not terribly familiar with that boat. I know my 32' Trojan (twin diesel) cruises at 21 knots with 400 HP total. I would think the Nauset 35 would require at least that much?
As far as costs go, a new marine diesel engine package in that power range is going to run in the 30k range. Labor will depend on how involved the swap is and without knowing what can be reused, its tough to say but I would expect from a low of 5k to as much as 15k.
Theres alway ways to save by doing some or all the labor yourself and using remanufactured or even used diesels... it all depends on what you feel comfortable with.
Modunlavy got it right! You will need at least 400+ hp at a weight of 13000 or so no more to get 18knt. New engine will be around 30K-35K with trans for a cummins, which is one of the engines you should consider, but that would depend service in your area. I have done a few re powers on downeast boats including two on my own boat and I would budget at least 15-20K to have it done depending on your shaft clearance and hardware. Definitely go 2-1 ratio on this boat even if it means redoing the shaft angle on the keel and a drop skeg. Seen a couple Bruno's done with 435hp 3208 17-18knt cruise around 13000lbs weight, and with a lighter new tech 6cyl and Lifting rail, should give you 19 or so as long as you are light no fly bridge that some have. JD's are good engines but do check on service availability as there are less of them around. Big and heavy so you will need a engine box if that is a concern. Fuel burn will be in the 15-17gph range at this HP. Good luck
Chances are if you have it done in a good shop that you'll be getting close to $40K by the time you have everything replaced that usually needs replacing in a repower, especially in this case where there is a switch from gas to diesel. If money is an issue see if you can get your current motor rebuilt instead.
Fortunately, there are several great choices in diesel powerplants for your re-power project. First, based upon my limited experience, I would be looking in the 400 HP range to give you the performance and grunt you are looking for from that hull. The Bruno Stillman hulls are great, and they were built like a tank and a 20 knot (+/-) cruise speed will be very sweet.
The Yanmar 400-440HP motor would be at the top of my list along with the Volvo TAMD series. either of these will not only give you the performance you want, but are extremely reliable. The Volvo having the electronic controls and a bit better fuel economy, in my experience.
Cummins, with their Q-series is should also be considered as should Cats C series motors in that HP range.
I have has some experience with the John Deere Marine powerplants and have nothing but praise for them.....if weight is not a consideration. They are flawless performers in full displacement trawlers that I have been on with them.
If money is no object and you want (what I consider) to be the true Rolls Royce of power for your boat, then Lugger is thee only way to go. Reliable as an anvil and great economy. Alaska Diesel (parent company of Lugger) has a sterling reputaiton for being a top notch outfit. The Northern Lights Gen sets they make are also great!
Now, if only M.A.N. had a motor in that HP range!
"The problem with life is that no one ever get's out of it alive"
downeast diesel repower 
