Repower questions

Have you done any reasonble weight estimates of the boat as finished? Before finally homing in on the engine solution, you must know how much it/they have to push around!

Then to gear ratios and propellers: If you start from scratch, there is no reason to restrict propeller dia to 14". That leads to low efficiency and a prop that is very load sensitive. The propeller disc area must be selected from the combination thrust versus speed.

What you are doing here is typical backwards engineering. Please take no offence; I am trying to make you take your decisions in the correct order. There are sooooo many lousy performers around, that are the result of starting in the "engine end", because there was a cheap setup on a dealers shelf somewhere!

Start with a weight estimate, including EVERYTHING that you are going to carry onboard over the next three years, then add crew, passengers, fuel, range of possible engine weights and THEN add at least 10 %!

Next, decide what speed you want; top and cruising. With this at hand, we can say what power and what propeller area you need. Then, and not until then, it is time to do the engine-prop matching for the variety of engine combinations you have at hand. Just DO NOT go for the xxx+yyy that is offered you at a bargain prize; its no bargain if is the wrong stuff, unless you are a collector!

All amateurs start with getting crazy about having the engine at hand first, then they spend two years producing dust that collects on the unprotected engines sitting in a corner of the shed at best; more often sitting in the boat. Now its your chance to make it right!

 

Here is a link to a boat that is what mine was for looks. Mine wont have all the foo foo this one does, but not sure how much weight to deduct for the cabin, head, bbq etc. I will have a small pilot house like a Shamrock.

This one gives stats on speed etc with a comparable hp diesel. So I guess its a good comp. BTW, my boat weighd 4300 lbs with the GM 350 when new.

http://classified.nauticexpo.com/small-ads-used-boat-classifieds/uniflite-salty-pup-45461.html

 

Guess I didnt realize I was going that far off course. I was trying to stay in the same hp range as original, or maybe a bit of an increase. (guy thing?) I wanted diesel to get away from the gas issues. I, maybe wrongly assumed with all the original upper house gone, it would weigh a fair bit less. Therefore getting more out of a lighter hull.???

I thought twins would be better/safer and only have one fuel source/type. By going inboard, I dont have the dreaded doghouse in the way. The VW 1.9's are light, have the power I wanted and are small enough to have no doghouse at all. Just a full width step up into the PH.

Above I thought I read that staying with a lower rpm/torque, ie the 6.5, I would leave the current gear in place.

Im by no means offended. Im just trying to do this, get decent results to go fishing with, and keep the cost to a minimum for the first real project.

So bring on the ideas!

 

Aah, now I see what you have (or are going to have.....). Start looking for one Cummins 5.9 BT 210 hp" or a BTA 250 hp, of the previous engine generation (mechanical injection, 2 valves/cyl) with a 1.5:1 transmission!!! Its weight, complete with all heat exc, and ZF/IRM tranny is 568 kg (1252 lb). Compared to the advertized boat with the Yanmar 240 hp less all the surplus superstructure weight, you will come out with a LOWER displacement. NOTE most of those hydraulic transmissions come with a trolling valve at a very marginal extra cost! That will allow you to lurch around at any pace for all day without an outboard hanging aft.

There are a number of positive points in this arrangement: The Cummins comes with its engine oil cooler integrated into the fresh water system (no extra piping or blocking by sea-weed, always correct oil temp), no timing belts for camdrive (NO engine with belt for this purpose should be allowed in a marine application!!!!), single engine has no syncronizing problems (double arr very often loads engines unevenly, causing vibration and wear problems).

This engine will outrun you in terms of life time; it needs one intake with a mud trap for cooling water, one outlet for xh, two vents for air in/out, and fuel in/return, including one coarse fuel filter/water separator (preferably of the twin version so you can switch underway), one throttle and one tranny control cable, clean fuel an lubricant, and away you go! Stop this nonsense about marinizing multiple high speed car engines for this boat; you will never get fishin'!

Start looking for that engine, get a dimensional dwg for it (evt make a Styrofoam mockup), and get started with the restoration job. Sooner or later in that process, there will pop up a 5.9 Cummins.

Now I would like to know how long is the engine room in the boat, transom to firewall? I'll see if I can post a few pics on an outboard tunnel for a similar IVECO 5.9 l six, 270 hp arrangement. BTW do you have IVECO/Fiats around? Their six is really a nice engine, quite similar to the Cummins, but slightly more compact and lighter.

 

And join boat diesel.com and use their software. They have calculator soft ware for shafts, wheel sizing, and performance of boats with engine options and gear options in hulls. Baeckmo's advice on weight is spot on. I would increase the additional weight factor to 15% because, items creep onto boats.

 

I have 11 feet from firewall to transome exhaust fitting. Wide open bay. The only Iveco found was 135hp. I did find a 6.5 rebuild with the low compression pistons etc.. Lots of the 5.9's, but need to find out how to tell what hp they have. Most seem to be 160-190 range so far.

 

That´s long enough for any of the 6 litre sixes. If my memory is correct, you need about minimum 2 meters (short of 7 ft).

!35 hp Iveco is probably the 4-cylinder. Unblown 6-cyls (8060 or 8061 series) come from 140 to 165 hp, then they get a turbo w/o intercooler, resulting in 200 hp. With ic you get 250 and 330 hp; the 250 version to be preferred before the 330.

 

The only one I found was in a wrecked truck. He said that when it was running, it cost so much to keep that truck on the road (parts prices) that he is scrapping it out.

The aftermarket marine exhaust guy I talked to said they could make it for just about any power. Id rather stay closer to "off the shelf" if possible. Cummins seems to be very widely used and parts are widely available.

I found a pair (one parts) of marine Nanni/Mercedes 6 cyl. It would be cool to find some already marinized that are less than 10K. I found a pair Nissan/Chrysler 6 cyl local. But theyre only 90hp and weigh 1800lbs ea. Not good.............. Looking like the cummins route is safest bet I guess.

I found the transmission you mentioned. It even had the trolling valve you listed. I hadnt ever heard of them before and there is was. Right after your post.

 

http://www.dieselenginetrader.com/

good luck.

 

http://www.fishtheclassic.net/forums/album.php?albumid=113 This is a short version of what I envision mine to be when done. Lots of room, but a place to get out of the weather too.

 

Joined Boatdiesel.com. Tons of info over there. It shows 40 knots with the 5.9. Im thinking I could do with less than that, There are a couple Perkins Marne 165-195hp available. Thats still 30 knts.

 

Everybody left? No opinions for over a week. I have two engine setups ready to buy and get building.

#1 An older running Perkins 6.354 marine engine and transmission, needs alternator work. At a marina that was to install it in a boat that sank before it could be installed. Owner gave up on project. But, its only 165hp and Im wondering/worried if thats enough. Boatdiesel.com says I can drop it in with the shaft/gear I have now.

#2 A 2004 Cummins 5.9 210 hp with a ZF transmission. Its not marinized, but I have the heat exchangers available. That 210 can be boosted quite a bit if needed. The transmission is new 1-1.

??????? I'd love to have the one thats all ready to go. But there is shipping and the possibility its not as advertised. Its about $600 less, but I dont want to pay less and be short. I cant find much on that Perkins either. Some here that say they "can" run forever.

Chris

 

No reason to repeat what we have already said. Reread post no 49, first sentence! In the mean time, start working on your boat, when that is steaming on there will be an engine as well.

BTW, that old Perkins is best used for mooring!

 

Baeckmo,

Thanks for the Perkins info. I was waiting to see if you found the photos of the gear installation you mentioned in that same post at the bottom. Dont I need to know the final hull shape before I go further with the build?

Thanks, Chris

 

go for the newer one the perkins was a load of crap in the 1970s so it probably has been running for ever ....