Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

As some of you know, I have a 23SF that was originally a diesel inboard. Currently the boat is bracketed with an Aluminum bracket with twin 225's with the prop pocket glassed over. This is a future job, but I am rebuilding the boat with one of these choices in mind. Even if I rebuild the original transom myself, the cost of the new bracket, motors, rigging, ect. is around 30K. Since I already have the stringers and motor bay intack, and the old saddle tanks still in place I would not have as much retro-fitting. I would then, not have to rebuild the transom and would have a transom outdrive for a more efficient prop position for speed (40+ knots)and the benefits of trim/tilt here where it's shallow all over the place. I am thinking of the efficiency/lower center of gravity and better boat balance/Ect.. I think my price would the same or less with the diesel. I understand about the outdrive seal sitting in the water. I am looking for responses regarding initial cost, maintenance costs, boat balance, and resale.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Danny,

What's going on? I thought that you would have the boat in the water by now.

What's your current time table?

Peter

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Peter- The 18SF just got picked up today :cool:.
My buyer is trailering it to South Carolina. I wish I was using the 23 now. Investment House sale fell through. I will use the 23 as is, but am planning the big overhaul down the road. I will be getting good use of the boat starting very soon, but I am thinking long term. I am soliciting feedback on my best served plan for the "highest and best use" in that 30K area.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

My neighbor had one of the jackshafted 23's back in the eighties and although he had problems with the universal joints on occasion the overall performance of the boat was very good. I dont remember what the numbers were though.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Snookered,

I can tell you from experience, putting in a Jackshafted Diesel is an expensive proposition, but in the long run I think it will pay off. My engine alone was in the 30K area,(D6-350). Mine is a 27 and is almost done. I had an inboard 454, with no pocket, but the hull was cut flat with a 24" PAD. I ended up installing new Stringers for the Engine mounts, and beefed up the original Seacraft stringers as well. My boat is still at the glass shop, a 2 week Paint job has turned into a 2 month Gelcoat Job. I am hoping to splash her by Labor day in time for Tuna. Then I can let you know if it was worth it. If I had a 23 inboard, and the pocket was glassed over and the Engine mounts were good, and the fuel tanks were ok, then I would drop in a VP D3 Jackshafted to a Composite or Aluminum DP drive.It is an awesome little package that weighs about 720 lbs (+ the shaft weight)maybe another 80 pounds. I think you would be looking at 30 Knots top end, cruise at 25 and get better than 5 MPG, that is just a guess from everything I have read.

Good Luck !!!

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Craig-That sounds like it was a good set-up minus the joints. There are not too many out there. kerneltugboat- Thanks for the prospective. Your project is going to payoff huge dividends. I am looking forward to hearing about the Labor Day splash! I checked into the Steyr 256 - (Nestor's recommendation), but Inmar Marine only puts those on ski boats?! The Albe 242 is the big diesel/jackshaft producer with a similar size and older hull. They use the D-4 260 with the duoprop outdrive. The Silverhawk should have that set-up.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I have a Seacraft, but also a TrueWorld Marine 288 (28'8" x 9'3" wide) with a Yanmar 315 hp turbo diesel mounted amidship jackshafted to a Bravo3X Merc outdrive. I turn 22" pitch props, carry 130 gallons of diesel, have an honest 450 to 500 mile range, cruise at 28 to 30 mph with a top end of 40mph. Not too bad for a boat that weighs close to 9500 pounds fully loaded. Yanmar offers this package for repowers, and I believe it is around your price range. I can't say enough nice things about this setup. Runs offshore or shallow. Not worried about blowing up either.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

CC-that True World Marine 28 is a sweet ride. those are some incredible #'s :eek:. What kind of maintenence costs do have annually? That Yanmar is a beast.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I checked with Silver Hawk on-line for the diesel jackshaft option, they have one with no price quoted. They are in the 115K area with their top packages :o. they cameout with another version of a stretched SC23 @26 feet this year.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

Isn't the Albin the same??

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

it should the same basic 26 between 2 different companies. I bet they are very differently rigged though. I read a thread on THT that had one of the owners of Silverhawk say that he had never seen the Albin 26 which has been out for a while?!

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

kerneltugboat,

I agree the D3 looks like a nice small package, but do you think it would really move the boat that well? Largest motor is 190hp.

I saw this engine package a few months ago, but didn't give it much consideration because of the HP rating. Should I reconsider?

Thanks, Jim

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

Just a note on the Silverhawk. I live right down the street from the Silverhawk Plant. In fact I supply Silverhawk with all of their T-tops and rails. The 26 isn't a stretched 24, it started out that way but they trashed the idea and started over. The boat will be a 28ft with a new shear line and higher free board to balance it out. Outboards on a bracket will be on the first one. I'm not sure about an I/O version. Look for the 28 at the AC in water show in Sept.

As far as the I/O version of the 24. The 24 with the 383 Mercruiser Stroker motor runs a solid 53mph on the GPS full of fuel and 2 guys. It is the Bravo 3 drive so, the boat has alot of balls. There has been some talk of doing a jack shaft version in the future.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

The boat has a closed cooling system (fresh water cooled), so all I have had to do is run pink antifreeze thru the intake, change the zinc anodes, the oil, filters and wash the air filter. Less than 200 bucks per year. I have a floscan on the boat so I know the fuel burn numbers are right (plus I check it on fill ups before resetting). Speed is by GPS (Furuno Navnet). I repowered another boat I own 3 years ago with a 5.7l bravo1 set up for about 15k. It burned about 10 to 12 gph at cruise (25mph). Haven't used it but a couple of times since I got the TWM with the Yanmar.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

cc - I recently read an article by Dave Pascoe on yachtsurvey.com that Yanmar used to use a heat exchanger with brass tubes in an aluminum casting. Do you know if they have changed that set up to eliminate the potential galvanic corrosion problems?

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

it looks like the prices of a used diesel boat make a good argument for a "take out" and install in my boat, then swap with a gas motor, then resell the donor boat. any thoughts??

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Jim,

I think it would, just by reading several articles on boats with Similar weight in inboard form. If you go to VP's Website they have a repower configurator and I put in a weight of 4500 lbs at 23 ft and it calculates 34.5 Knots Top End with the D3-190 with the duoprop, so I figured 30 Knots may be realistic, but it may do more. My boat should be around 36-38 Knots top end I should cruise at 30 Knots under 10 GPH, I am hoping to get closer to the True World Fuel numbers at 22-25 knots. You can also see the Fuel burn charts and it looks like the D3 would burn 5 GPH at 3250 RPM, wich I figure should be pushing it between 23-25 knots. We will not really know until someone puts one in a 23, but I think it would be an awesome ride. Also, the True World Marine 28' boats were the inspiration to do what I did with mine. I went with VP because my local mechanic was a dealer and I wanted one company to deal with if I had an issue, but the Yanmar engine and Mercruiser drives are great as well. The only downside to the D3 would be it is all aluminum as opposed to my Cast Iron D6, but for normal use it should be fine. I think the D4 is a little too heavy for a 23 (1400lbs) vs the 720 of the D3. I also considered the Steyr, at 250 HP, it is very light as well and may work in the 23 mated to a Bravo I Diesel drive, but I stuck with VP. I will let you know how it goes in a few weeks.

Dan

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Dan-Your right the D-4 would be too heavy @ 1400 lbs. Jim- for VP, I agree with Dan on the D-3. It would be the one to go with. The performance and fuel #'s are solid on these motors. Anyone know the motor and weight of the original Diesel installed in the 23 back in the 70's? I am checking on the Yanmar and Steyr for weight/price.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

bushwacker: I am not sure about the heat exchanger, I will check and post. I am almost sure it is not aluminum/brass. I think it may be monel.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I spoke with a a local shop in Bradenton that is a Steyr Dealer. I am getting a quote tomorrow on the 256. It sounds like the dealer network here in SW FLA is building up over the last year.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I believe they ran the Volvo TMD40 @ 165hp.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Thanks Scott. I am finding 1150 lbs. as the original weight of that Volvo motor. Diesels inboards are getting lighter and gas outboards have gotten heavier :D. The Styer 256 is around 700 lbs putting out 250 hp!

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Check out the pics I posted of the "Hawaiian" SeaCraft. As mentioned the hull is stretched to 26' and has a volvo AD41B 200 hP diesel in it. The boat is fast with the direct drive (low 30 knot range) and burns about 2 gph at trolling speed. They are much faster with the VP Douprop (mid to high 30 knot range). That may be attributed to the back end being flattened out vs. the original deep v of your classic. Most seasoned fishermen in Hawaii run diesel power (unless the boat is too small or they can't afford it) in their Classic SeaCrafts or 24' and 26' Yellowfins (modified SeaCraft hull). The first boats like my dad's were a bit heavier than the newer ones as they used a good amount of wood in the construction. My dad's boat was filled with seven Ahi from 110 lbs. up to 170 lbs. (Hawaiian name for Allison Tuna), over 700 lbs. of ice alone + brine, a crew of 3 weighing 140 lbs., 165 lbs. and 220 lbs. Plus all the rest of our gear (we fish 5 Penn 130's). They came back in 15-20 ft. seas on the windward side of Oahu and the engine still had more throttle. Weather conditions didn't allow my dad to use more power and the motor was over 10 yrs. old. Hope this helps you decide and if you have anything you'd like to ask in specific give me a holler. Aloha, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Snookered,

I really like the Steyr, you may wan't to confirm one thing, I think it has Electronically controlled manual injection, just like my 6.5l Suburban, at the time they were not promoting common rail fuel injection. The common rail is supposed to be quieter and better on fuel. This was a few years ago, so they may have it now. Another thing I thought might be interesting is to jackshaft an I/O to a Inboard Seacraft with the pocket. I did notice when Albin went to I/O on their inboard diesel, they got rid of the pocket. I wonder if they tried it, or just figured they better enclose the pocket. I think it could be done, the motor would be higher, but the driveshaft should still clear the floor, although it would be close. It is a lot of work to do it and find out it don't work !!!! I think that is why it has not been done !!!

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I would think if the pocket was left in place and an I/O bolted to the transom, there wouldn't be enough clean water for the prop to bite into, causing a lot of cavitation/slippage.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Greg- Thanks for the details of your ride. Very cool modifications to consider as a strectched 23. Kerneltugboat-Thanks for the Steyr update on fuel delivery info. I got my quote on Friday and I am in sticker-shock :o. I am getting quotes of $26K for the 256 Steyr and VP outdrive. The quote is before shipping from Austria, and install. I am certain that Nestor's Steyr dealer quoted around $17K for the motor last year. The 26K is no-where close.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

The twins on a Seamark look good right around now :D. The Yanmar is better priced than the Steyr from what I have heard.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Snookerd, Thanks. You may want to look into a Cummins 210 hP. I think its referred to as the BT210. It's an older style mechanical injected motor. We were quoted about $12,800 + the cost of the gear (another $1k approx) to run a jackshsft set up in addition to the cost of a Bravo 3 outdrive. The motor is very reliable and parts availabililty is plentiful as the salesman told us the same block is used in heavy equipment and commercial trucks. The motor is rated medium duty vs. the old VP 200 and 235 hP motors being rated as light duty. I heard from a VP dealer on the East coast that VP stopped producing the mechanical motors because they can't get decent cores to rebuild the parts. Also, my local Cummins dealer told me the electronically controlled motors have to go into any boat commissioned from I believe 2005 (or something like that) in order to meet EPA regs. Any boat built before that being repowered can use the mechanical system.

The new electronically controlled motors are SWEET though ;)... I heard they are just as quiet as a 4 stroke outboard. Most fishermen in Hawaii are so used to the cast iron inline 6 format and mechanical injection that they are weary of the 4 cyl. aluminum blocks and electronic bugs that the new systems may have since they are 1st Gen. Take it easy and regardless of powerplant you defintely have an AWESOME fishing machine (SeaCraft ofcourse!). Aloha, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

guys, I ran oldport launches for like 8 years, and they all had small yanmars in them, 70-80 hp range, and we would put about 2000 hours on them a season with little to no maint. Those things were/are bulletproof.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

there's a 25' Steiger around Homosassa with twin VP diesel sterndrives. I've been told by a third part that they're 140 hp models. I don't have any other info.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Greg-
That Cummins price sounds good. I need to get more info on that motor and the Yanmars. I know that I will get the price down to a lower number than high 20's installed.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I have looked at the rebuilt Steyr motor route and have come up with an estimate of $13,000 for the 256 model motor. It looks like the install with a VP DP Outdrive would be in the $18,000 area. Much better price option than the $25-30K

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

How is your repower project coming along? Did you purchase the Steyr Diesel? Hope its all coming together. Aloha, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Greg- I am just setting things up for down the road. When I started the thread, I was and still am just planning. You better believe I will be posting what I get into when I open the boat up. I am still looking for input from you and other inboard motor heads. I am considering removing one of my 225's to reduce weight while I use the boat.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Thanks for the report Danny. I did some online research on the Steyr 256 yesterday. Have to say the motor looks impressive and mated to a Bravo III...Sweet. I talked it over with my father and he has still decided to stick with the Cummins 6BTA5.9 315 hp. As a Finance/Econ major turned construction worker I pointed out to my father that with the Euro holding an advantage over the US Dollar and having to be imported (Trade tarriffs, currency exchange, import taxes, etc.) that down the road the Cummins will most likely be the most cost effective powerplant. Also it feels good to support our own country's economy. Buy America! :) As mentioned before the Cummins sales rep told us the B platform has been around next to forever and being used in construction equipment, US Government applications and I am pretty sure its the same motor in the Dodge diesel p/u parts availability, cores and rebuilt motor supply shouldn't be a problem. I talked to a friend of mine who put me in contact with another friend of his that has the same hull (23' seacraft stretched to 26') that I am helping my father rebuild. Hopefully we will get a chance to look at his boat and get photos/measurements as he had the 210 Cummins set up with a V-drive and upgraded to the 315. I will post pics if we get them so you can take a look. Most fishermen here use the 210 in their 23' Seacrafts/ 24' Yellowfins. Talk to you later, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Greg-
I agree on the value of the Cummins. The Steyr is great on weight to HP, but not price or as available as the Cummins. I am going to check further into the 2 Cummins diesels you have mentioned. I would love to see your info on the set-up you are checking into. Anyone you know have this motor in a 23SC with that 315 Cummins? 1200lbs seems at the top of the scale for a unmodified 23 hull.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Danny,

I think the 315 hP cummins is a bit heavy for a 23. You may want to talk it over with a full time boat builder like Hermco. The guys here will go up to a 250 hP in a 24 ft. Yellowfin (modified SeaCraft, they made a plug with the v a bit shallower and cast a mold to shoot an entirely new hull which is called a Yellowfin 24 or 24 Saltwater, same process for the 26 Yellowfin like my Dad's) using a v-drive set up. My friend has the 250 cummins and v-drive in his 24. When I have time I need to meet up with him and get pics of his boat and measurements. Will keep you posted. Just to let you know the 250 cummins may not be available as a rebuild unless you have cummins build it. As mentioned earlier the cummins dealer in Hawaii told us only the 210 hP and 315 hP are available as off the self rebuilds. They can do the 250 or other configurations previously offered and a custom build charge will apply. He told us the main diff. between the 210 and 315 is that the 315 has bigger injectors and requires a significantly larger cooling system which is where the bulk of the weight comes from. The 315 weighs about 200 lbs. more than the 200 hP volvo with a 290 outdrive. Double check the specs to be sure. I believe I found the volvo specs on their website. They have a historical engine spec link for obsolete volvo engines. Hope you find this of help. Take it easy, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

Danny,

I have some pics of my friends boat. A 24' Yellowfin (modifed SeaCraft) with a 5.9BT 250 hP cummins and Hurth V-drive set up. PM me your email and I will send you some pics. Merry Christmas, Greg

Re: Inboard Diesel Jackshafted Vs. Twins on a Seamark
 

I just found out that my 23SF was one of the original 6 jackshafted inboards built and was diesel.

Re: Inboard Diesel Jackshafted Vs. Twins on a Seam
 

Hey Snookered,
A lot of the old Morgan 24`s used the B210 and there are a lot around Boca Grande as they were shallow draft semi displacement hulls and perfect for drifting the pass. Not well known and you can pick them up cheaply. Since you can get 10 - 20,000 hrs outta them that may be a thought. As Greg said everybody knows how to work on em and parts are easy. Cheap repower and sell the hull.
GFS