Best diesel engine for 24' radon repower

One_Leg

Ret. Comm. Diver Medic
May 11, 2007
5,605
2,107
You're mined!
www.csicop.org
Name
Alan
Boat
1967 Cobia Cuddy Cabin/Evinrude Looper
Cummins
 
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oceanjake

Member
May 10, 2005
955
283
Long Beach
Name
Jake
Boat
36’ Tiara Express
You should ask Tony Athens, who will probably tell you a QSB. In any event, if you want the reliability and longevity that differentiate diesels from gas, you should stay away for the hi-revving diesels, like Yanmars.
I think high revs go hand in hand with smaller displacement. Those yanmars are actually pretty great little engines depending on the size of boat.
 
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salty nuts

I Should Upgrade My Account
Jun 2, 2004
1,377
462
Camarillo
Name
Tim Mohawk
Boat
25 Davis Rockharbor Volvo D4-260 TailChaser
Doubt you will fit a Cummins in a 24’ radon. If you’re hell bent on a diesel it’s Volvo or yanmar. Either which are expensive parts wise. What are you going to be using the boat for? Where do you fish? How far do you plan on going? Why diesel?
 
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May 13, 2004
476
572
74
Long Beach and points due west
Name
Bob Ballew
Boat
2520 Parker with twin 200 Yamahas
Volvo parts mucho expensive...and, Volvo doesn't much care about customer service..ordering from overseas can be a long wait...alum block diesels don't hold up like the old cast iron monsters...mechanics get lots of work at about the 1,000 hour mark...
...I would throw a 454 gas engine in it and use the savings to go like hell....
 

John Senesac

Run-A-Muck
Sep 17, 2019
37
35
25
Torrance
Name
RunAMuck
Boat
Nautica
I want to be doing a lot of offshore long hauls. I want a diesel for fuel economy reliability, I feel much more confident with diesel engines. I have a my Cummins 4bt and love it.
 

Mr Lingcod

Almost A Member
Mar 20, 2017
128
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Santa Barbara
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Jesse
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The Last Soviet
All the 25 Rock Harbors (Radon hull design) have D4 225s or 260s. Most owners I know seem to always just want a bit more. I know two guys that converted to brackets and OBs that absolutely light up when you talk to them about it. Any reason why this isn't considered for a 24 Radon?
 

knot keely

Member
Aug 9, 2014
864
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The Bight
Name
Dan
Boat
Anderson 22 - Slingshot
I want to be doing a lot of offshore long hauls. I want a diesel for fuel economy reliability, I feel much more confident with diesel engines. I have a my Cummins 4bt and love it.

Some things to consider:

Cummins are not outdrive friendly. Plan on a new outdrive every couple seasons. Unless, you go with a Konrad which are not cheap, and require a transmission. That’s a lot of real estate getting taken up on a 24’ boat. You could go with a shaft or V-drive for reliability, but again, that will eat up a ton of space on a boat this size.

The high-revving diesels like Yanmar or Volvo are a better fit, and play nicer with outdrives, but cost/maintenance/parts can be stupid expensive.

If you went outboard, you could gain a ton of deck and under-deck space and have room for enormous fuel tanks (solving the range issue). You could also run twins and gain some redundancy/safety on your long trips (solving your reliability concern).

Whatever you do, good luck and please post your build.

:cheers:
 

John Senesac

Run-A-Muck
Sep 17, 2019
37
35
25
Torrance
Name
RunAMuck
Boat
Nautica
I do like the idea of freeing up the deck and eliminating the engine hatch, by putting some outboards.

I have converted a Blackman to an outboard and I feel it threw off the ride of the boat.

If I was doing outboards I would just want it to be done right so all the weight would be distrubted properly, I don't know if an Armstrong bracket is the way to go or custom built off the transom with the right degree.

I also want to set this boat up for where the resale value would be better
 

dctrjayyy

Member
Jun 27, 2005
412
225
43
Tustin
Name
Joshua
Boat
whaler
I do like the idea of freeing up the deck and eliminating the engine hatch, by putting some outboards.

I have converted a Blackman to an outboard and I feel it threw off the ride of the boat.

If I was doing outboards I would just want it to be done right so all the weight would be distrubted properly, I don't know if an Armstrong bracket is the way to go or custom built off the transom with the right degree.

I also want to set this boat up for where the resale value would be better
You are on it. The consensus is that the Armstrong brackets aren't the best for the 24ish Radon hull, you need custom following the lines. Price works out to be the same anyway now. Outboards give you good speed but surprisingly low economy for a heavy 24 like yours when compared to the diesel. Resale depends on the buyer I think. Commercial is going to want the diesel. For the rec guys, there probably isn't a boat in higher demand than a Radon hull with outboards right now in Socal.
 
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