23 IB - Anyone Running a Diesel?

[John3325]

As I lay out plans for my 23 IB I am curious, does anyone on the site have a diesel that they run in one of these straight inboard hulls?

Boatyard I do work for always is taking in salvage jobs and junkers, so you never know if they get something in.....

I would imagine an inline 4 yanmar would be an awesome match in this hull, anyone have some experience/data they'd like to share?

From talking with a few people, their take is for how well you can get the hull to perform with a gas inboard setup, the Return on Investment is not there unless you put hundreds of hours on it every season (commercial use). This prompted me to see what you all think.

[caper]

There are diesel inboard conversions out there - I've seen several on the web - but I don't think any on this site. I recall reading they were it bit sluggish, but great sea boats.

[FLexpat]

I remember seeing at least one thread here about a Yanmar diesel in a 23 CC IB being run in the NE somewhere - I'm thinking it was a 6 but might have been a 4. IIRC, it had great performance...
Also, I know Metan did a jackshaft I/O Yanmar conversion (on Youtube) and maybe an IB Yanmar - reach out to them and see what they can tell you.

[deepsushi]

a couple of members have yanmar 230/240s 4 cylinders in their inboards (osead23 and highway12). One member has a 315 6 cylinder as well. I have seen boats with cummins 6btas and volvo 40 series as well.
The yanmar 4 is a direct replacement for the gas motors as you dont need to upgrade the shaft size to handle the torque. The diesel upgrade increases cruise speed to 25/27 knots vs 21/22 in gas powered inboards.

The yanmars arent available new anymore and the used ones are hard to find and usually fetch a high price. Yanmar is due to release a new 4lv series next year which will be a great option as they are common rail diesels in both 230 k and 250 hp.

[cc]

I have a 28' boat with a 315 hp, 6 cylinder yanmar pushing. I love it! It is so smooth, very quiet, a responds quickly. I get a tad over 3.2 statue miles per gallon running at 28 mph. Top end is 40mph. I have 400 hours on it. We also have a 1965 seacraft 19 bow rider Dad bought new. Thought about repowering it with a yanmar 4 cyl, but the original mercruiser runs so well. I can't say enough good about the yanmar.

[dginge]

I have a 23 sceptre with a 260 yanmar. 6 cylinder. I hold 76 gallons and could make it to Cuba on a tank. Ha. I love it. It's my favorite seacraft yet. It's a 1979 and has a bravo 3 IO. I have 330 hours on it and it was installed in 2001. I cruise at 31 mph and top out at 3800 Rpms and get 42-46 mph depending on load. I think it may be my forever boat but I've said that at least 6 times.

[John3325]

Thanks guys, great info so far. I do work for a boat salvage company so maybe I can put them on alert for a 4 cylinder/6 cylinder yanmar used.

They can't be much sluggish than it is now, top end of 40 mph sounds great to me for that hull.

[dginge]

You heard wrong. Yanmar diesels are the complete opposite of sluggish. Unless of course it has lost a cylinder or two!!!!

Originally Posted by caper

There are diesel inboard conversions out there - I've seen several on the web - but I don't think any on this site. I recall reading they were it bit sluggish, but great sea boats.

[BOBMX]

I have a 1976 23' Sceptre with a Yanmar 4LHA/240 hp and inboard v-drive. I fished this weekend out of Baja and ran a total of 210 miles in 2 days and burned 66 gallons of fuel averaging over 3 mpg running about 50/50 cruise and trolling at 7.5-8.5 knots. I run 2800 rpm's at 25 mph and top out 3200 rpm's at a shade over 30 mph. I headed out both days full of fuel, gear, ice and 3 guys on board. I think I could play around with different props and squeeze out another 1000 rpm's but she'll pull out of the hole and run the same numbers regardless of the load so the gain is not worth the hassle to me. From my experience this boats center of gravity with the weight of the diesel will push this hull through much bigger seas that my 23' center console is capable of. Sunday headed back in with winds 15-20 knots and didn't back down too much off my normal cruise and had a good ride. If I were going to build one now and this engine was available I wouldn't hesitate. It's reliable, economical, has tons of torque and leaves plenty of room in the engine compartment to work on it.

[John3325]

Thanks Bob, sounds like a good setup for you.

Anyone have some prior experience numbers ($$$) doing a gas to diesel repower conversion? Things that needed to be changed that some of us may not factor in ahead of time?