This forum contains 29 topics and 125 replies, and was last updated by  finalee2005 1 month ago.

Viewing 20 topics - 1 through 20 (of 29 total)
    • Cummins Marine Forum Topics
    • Repower 35 Henriques Pilothouse

      This topic has 9 replies, has 3 voices, and was last updated by finalee2005 1 month ago

      March 1, 2018 at 3:18 pm I have a 35 Maine Coaster pilothouse that I am considering downsizing the engine from a 420 to 370 Cummins Is this a reasonable possibility in theory. We use the boat for recreational fishing and don’t need a speed demon. Again this is a boat with a 4kw Onan genset, 300gallons of diesel max and 50 gallons of water if we were full. It is an 18000lb boat I need to repower but budget dictates and I’ve seen another similar boat a 34 Du…

      Started by:  finalee2005

      9 Replies
      May 10, 2019 at 7:38 am Good day All, This is a LOOONGGG overdue update: I’ve managed to get the engine out and will be replacing it with an (apple to apple) direct model replacement. 6CTA 8.3-M.2 Upon removing the current engine and tranny, it has been revealed, as expected that the coupling may need replacing. What is currently on the tranny is from VULKAN p/n# 1KT4110104. Is this something that you supply at Seaboard or is there an apple to apple upgrade as it…

      Last Post by:  finalee2005 posted: 1 month ago

    • Disassemble QSM11 to fit in to boat – then reassemble

      This topic has 5 replies, has 3 voices, and was last updated by Ed Fang 1 month ago

      April 29, 2019 at 10:24 am In the early stages of researching to potentially repower my 6v92/550 powered flybridge express. Currently an ideal time to explore since my DD need to be overhauled. This would be an inframe overhaul. but doing research and due diligence on a Cummins QSM11/630 potential overhaul. The engine can not be “dropped in” as the clearances in to the cabin and then the below engine room just doesnt have the clearance. So whatever happens,…

      Started by:  Ed Fang

      5 Replies
      April 30, 2019 at 4:44 am Rob. Thanks for the link. I literally found those last night and have already printed them out. Looks like the Cummins is 23 in longer than the 6v92. But in reality It’s probably 13in as the last part is what sticks out from the exhaust blower over the transmission which isn’t a big deal. It is about the same width and a few inches shorter in Height. I got the engine block length of 37in but couldn’t get more accurate measurements I’d …

      Last Post by:  Ed Fang posted: 1 month ago

    • 35 T Jason Repower

      This topic has 5 replies, has 2 voices, and was last updated by Warren Graybill 1 month ago

      April 27, 2019 at 11:31 am Right now I have a 35 T Jason commercial lobster boat that is powered with a bf6m 1015 Deutz rated at 443 HP. I have a 2” shaft swinging a 28×34 wheel. I have a zf 325 2:1 gear. I am looking into a QSC 8.3 500. My Deutz is a 2100 rpm engine. Would I be able to keep my zf 325 at 2:1? The gear is only 2 years old with less than 2k hours on it.

      Started by:  Warren Graybill

      5 Replies
      April 28, 2019 at 7:19 pm Thank you Tony! Fuel burn is not a concern. My concern was unfamiliarity with what the engine can handle, as it came in the boat when I bought it. Also not much support in this area. Most of the day is spends at idle hauling gear, and my runs are only 15-20 minutes average at cruise speed. Once I’m where I’m hauling gear i don’t hit cruise speed very often. I will run her a little harder and see where it brings me. Thank you for your help!

      Last Post by:  Warren Graybill posted: 1 month ago

    • installing 6bta w/ 220a

      This topic has 1 reply, has 2 voices, and was last updated by donald roth 2 months ago

      April 8, 2019 at 9:02 pm I am about ready to install my 6bta into my 1989 26′ Boca Grande. We have replaced the stringers so we are staring with a clean slate. Need to fab and install the mounts but am trying to figure out an easy way to determine where they need to be and the angle required. Does anyone have any insight on making a template or where i could buy/rent one for ease of making motor mounts on the stringers?

      Started by:  Andrew Piipponen

      1 Reply
      April 9, 2019 at 10:29 am Go to the “Tony’s tips” section on this website and read under the heading “Repowering your boat”. There is a wealth of information there! You can also find the dimensions there for your motor.

      Last Post by:  donald roth posted: 2 months ago

    • Propeller Cupping – 38 Bayliner

      This topic has 10 replies, has 3 voices, and was last updated by Nick 2 months ago

      April 2, 2019 at 8:53 am Hello…my name is Nick… I have a 1988 Bayliner 3870 repowered with Cummins 6BTA’s 5.9M’s, build 8206, Tranny gear at 2:1, WOT 2600…propellers 21x26x4 Nibral. My issue…I have some damage in the corner of the tunnel where the trailing edge of the prop has pitted a hole about 3/8″ deep apparently caused by water turbulence/cavitation. Right now I cruise at 2350RPM/16.5kts, WOT 2600RPM/22kts. I don’t w…

      Started by:  Nick

      10 Replies
      April 8, 2019 at 2:48 pm Steve wrote: Sir, Are those the original propellers and were they adjusted when the boat was repowered? I had my prop serviced by Wilmington Propeller Service in Southern California. Talking with numerous others (including a Long Beach Harbor Pilot who has a fishing boat a few slips down), Wilmington Prop Service has a stellar reputation in the shipping industry. The owner there told me that generally all props in tunnels should be cupped. He ex…

      Last Post by:  Nick posted: 2 months ago

    • What size engine to use in a TJason 35?

      This topic has 9 replies, has 4 voices, and was last updated by Don Zink 3 months ago

      March 7, 2019 at 10:32 am I am planning on having a 35 foot TJason built I was hoping the guys on here could help me out. I am trying to decide which engine to use. The QSL9 450 or the QSC 8.3 500. Also what gear would be a good match The boat will be a cruiser/ fishing boat but mostly used for cruising, with the hopes of doing the great loop and to take it to the Bahamas for extended cruises. The TJason is a lobster boat I would like a solid 18 knot cruise. The boat wi…

      Started by:  Don Zink

      9 Replies
      March 13, 2019 at 7:44 pm Tony, Thank you for your help. I did not understand the performance curves and was reading them wrong. After reading the article you directed me to I get it now.. Thanks again. Don Don Zink

      Last Post by:  Don Zink posted: 3 months ago

    • 86 Bertram 35 repower options

      This topic has 2 replies, has 2 voices, and was last updated by Danny Sunkel 9 months ago

      September 13, 2018 at 3:04 am Hi, I have an Aussie built 86 Bertram 35. Has twin factory Green Disprins- 255hp Volvo TAMD60C, Twindisc 502 with 2.00 ratio and 10 degrees down angle. Boat weighs 10.5-11.5 tonne depending on load. I do about 400 hours a year Trolling 7 knots @1150 Cruise 16 @ 2200 Tops out 22-23 @ 2800 WOT Yes I know these hulls eat Hp… One engine out and needs a major birthday so time for repower considerations. We are coming into summer here so it’…

      Started by:  Danny Sunkel

      2 Replies
      September 16, 2018 at 5:00 pm Thanks for the response Tony, The rebranded thing was just that in NZ and Austrailia there are a lot of Bertrams that are branded as Carribeans. International Marine in Austrailia have some kind of licence to reproduce them down here. Mine was built in Aussie in 86 still under the Bertram name. Its irrelevant anyway as they are the same boat. Drop me an email and lets talk about these options.

      Last Post by:  Danny Sunkel posted: 9 months ago

    • Thinking of re-powering from Cat to Cummins

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 9 months ago

      September 16, 2018 at 9:34 am Hey All: I’m new to this site. I have a question, I have a pair of T/3208TA 375 Cats w/TD 507 gears with approx. 4k hours. I have an opportunty to replace them with a pair of QSB 5.9 480hp with TD MG5061A 1.54:1 gears @ < 100 hrs. The boat is a 1988 37′ Topaz which I use for charter fishing,approximate displacement of 20k #’s. Im wondering what and if this would be a good move ? I like the idea of the smaller motor (inline) …

      Started by:  Kenny Keen

      1 Reply
      September 16, 2018 at 3:14 pm Post your current gear ratio w/ the CATS , your current WOT RPM and vessel speed, current vessel speed at 2300 rpm, and most important, your current prop specs and engine HP. I seriously doubt you could use a 1.5 R gear. For propping purposes, this engine need to see 3500 RPM. Tony Tony Athens Seaboard Founder Go here for the latest stuff we put together and share for all to see:

      Last Post by:  Tony Athens posted: 9 months ago

    • Cummins repower

      This topic has 2 replies, has 3 voices, and was last updated by Bill Desmarais 9 months ago

      September 13, 2018 at 11:14 am Hi, I have a 1989 26′ Boca Grande i am in the process of redoing. Boat weighs roughly 5500 lbs just the hull. 26′ long 9’6 beam. Boat currently has a volvo TAMD61a which weighs roughly 1800 lbs and puts out ~300 hp. Im looking to repower with a cummins around the 250-300 mark. Ive got my eyes on one that is a 270 hp. Any recommendations? i can pretty much do whatever i want with it because the hull is basically stripped. Ive th…

      Started by:  Andrew Piipponen

      2 Replies
      September 15, 2018 at 6:34 pm Rob Schepis wrote: There’s nothing not to like about the 270B. Lower RPM and JWAC so no salt water aftercooler maintenance regimen.. Do you have the serial number of the one you “got your eyes on” ? Is it new recon or RTO or ?? And what does this mean ? “I’ve thought about swapping the cam for a 370 hp marine cam into this 270 im looking at.” any chance “the 270” is a non marine ? same question as Rob to the OP? ? R…

      Last Post by:  Bill Desmarais posted: 9 months ago

    • Repower Question

      This topic has 6 replies, has 5 voices, and was last updated by Rick Smith 9 months ago

      August 10, 2018 at 10:03 am I’m a new registered user, and I’d like to ask you a few questions and hopefully anyone can be of some help. sbmar website is great btw. I am interested in a purchase of a 1998 Maxum 4100 SCB, but it has 330hp Cummins 6BTA’s, and I think that is not enough engine for that weight boat. I could be wrong, but while I know some may say buy an express boat if you want something that does around 22knots, but I am leaning towards a Se…

      Started by:  Carmen L Spagnolo

      6 Replies
      August 24, 2018 at 10:56 am Carmen, Just as an FYI, I purchased a 2005 Maxum 3700 CY, Twin 6BTA’s 5.9 330hp. Not sure of the weight difference of the 41′ but they have ample power. I cruise at 2400rpm (22mph) Digitalrls

      Last Post by:  Rick Smith posted: 9 months ago

    • Re-Powering 1999 26' Shamrock Express

      This topic has 4 replies, has 3 voices, and was last updated by john 11 months ago

      July 9, 2018 at 10:29 am Hi from the East Cost, I have been considering to re-power the 99 shamrock 26′ express from the 5.7 gas Sea max for long time to power Diesel to get more fuel efficiency per Gal and long range . what is the right eng application or the right fit for this 99 26′ Express. Is Cummins like 6BT 215hp~250hp with the current ZF to keep the existing 1 1/4 shaft will be the right fit for this project ? what is the cost associated with …

      Started by:  Al

      4 Replies
      July 10, 2018 at 5:30 pm I have a friend that has that has that same boat with a cummins 6b 210. They came as a option. To me putting a diesel in a boat like this is a great project. Is it always the right choice?? Going from gas to diesel requires a lot of work. Some of these boats with a diesel in it might be a better way to go. Not trying to burst your bubble just putting it in perspective. I would do a little research and there is a owners club with a ton of info.

      Last Post by:  john posted: 11 months ago

    • Unspported Shaft Length

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 1 year ago

      May 19, 2018 at 9:01 pm Hell Tony and All, I’m considering a repower of a fiberglass keel boat. My calculations show a 28″ to 30″ length of shaft between the hull shaft log forward to the shaft/tranny coupler. Figure 380 QSB 5.9 Recon power, 8 degree ZF85A gear, 2:1 gear swinging a 22X19 four blade more or less. TBD . Prop shaft diameter 1.75 inch. 20/40 rule apply here ? No less than 20 X shaft diameter between bearings? = 35″ No more tha…

      Started by:  Bill Desmarais

      1 Reply
      May 20, 2018 at 1:46 pm Am missing total shaft length? Flexible or rigid engine mounts? Flexible or rigid shaft seal/log? Tony Tony Athens Seaboard Founder Go here for the latest stuff we put together and share for all to see:

      Last Post by:  Tony Athens posted: 1 year ago

    • Transmission Clearance to Hull

      This topic has 2 replies, has 2 voices, and was last updated by Mike P 1 year ago

      May 12, 2018 at 8:10 pm I am currently in the middle of a repower project. In order to get good shaft alignment, I need to have the engine sitting low in the boat, with the corner of the ZF220A only clearing the bottom of the boat by about 3/8″ on the outboard side. Is this too close? Is there a rule of thumb or a standard for this? Appreciate any input. -Mike-

      Started by:  Mike P

      2 Replies
      May 14, 2018 at 9:01 pm Tony, A fiberglass boat, a 37′ SeaRay. The stringers looked wimpy to me so I added 3/4″ of plywood that was glassed in, transom to forward engine room bulkhead. Mounts are 1/2″ aluminum “L” channel with 1/2″ backing to sandwich the top of the stringers, each bracket being 12″ long. I used new Barry mounts I got from Cummins. Sorry, no pictures, my phone dropped and ceased working today!

      Last Post by:  Mike P posted: 1 year ago

    • 1997 Bertram 36 Repower

      This topic has 13 replies, has 8 voices, and was last updated by Tim Schantz 1 year ago

      December 27, 2017 at 3:03 pm We are considering a purchase of a 1997 Bertram 36 with Cummins 450 Diamond engines. Approximately 1800 hours. Engines appear to be in good shape (sea trial and inspection pending), but the current owner has told us its not very fuel efficient above 1800 RPMs. Displacement is 30,000 lbs dry. Owner says at 1850 RPMs it is 17 knots and ~24 GPH, which seems a bit higher than the published power curves for the 450C Fuel efficiency, no smoke/fume…

      Started by:  Tim Flynn

      13 Replies
      May 2, 2018 at 8:12 am I’m a little late to the party here by the looks of it! I figured I would chime in anyway . I just completed a repower of my 36 Bertram Moppie. The boat originally had 430hp Volvos in it. I repowered with a set of 550hp QSB6.7’s. From my experience your fuel burn numbers at 1800 don’t seem too far off. This hull does not like speeds below 20 knots, it’s like it is fighting itself to plane out. With the Volvo’…

      Last Post by:  Tim Schantz posted: 1 year ago

    • Possible shamrock repower

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 1 year ago

      March 21, 2018 at 8:50 am Thinking about repowering a 1987 26 shamrock stalker. Boat weighs about 6000 lbs dry currently with a pleasure craftt 350 gas direct drive inboard. Boat will be used mostly in Arkansas but trailered to coast for some “real” fishing and diving adventures. Currently has 54 gal port and starboard fuel tanks total 108 with about 100 gal usable. I would like to increase speed thinking of around 350 to 380 hp Cummins 6bta? Currentl…

      Started by:  John Kurtz

      1 Reply
      April 30, 2018 at 1:53 pm John, Somehow I missed this post–Sorry.. Anyway, I have repowered 2 Shamrock “Keel Drives” like yours and both turned out really well.. #1 was done using a Cummins 6BT 210 and a Velvet drive 1:1 gear ( like a ski-boat) , and the other one we used a Yanmar 6LPA 315–We called it the “Sham Rocket”.. Very fast and very smooth……………………………….Later…

      Last Post by:  Tony Athens posted: 1 year ago

    • Possible shamrock repower

      This topic has 1 reply, has 2 voices, and was last updated by john 1 year ago

      March 22, 2018 at 5:55 am Thinking of repowering a 1987 26′ shamrock stalker…..used mainly in freshwater lake but would like to trailer the boat to the coast for some fishing and diving adventures I was thinking about 380 ish hp. Boat weighs about 6000 pounds dry with the 350. Would like to gain speed, fuel efficiency, and dependability Currently has port and starboard fuel tanks 54 gal each Also have some concerns about prop clearance shaft size runnin…

      Started by:  John Kurtz

      1 Reply
      March 22, 2018 at 8:46 am I take it you want to put a diesel in it. I’m a big fan of shamrocks. They put a lot b series in the 26 shamrocks. Most were 210 hp. Big difference from that and 380 hp. Personally I think I would look for one of those. You have a ton of issues to deal with. Exhaust, fuel returns, shaft sizing, will it fit, prop clearance to name a few. This site has a lot of info on shamrocks Great project though goo…

      Last Post by:  john posted: 1 year ago

    • Repowering 1990 luhrs 320

      This topic has 9 replies, has 3 voices, and was last updated by Tony Athens 1 year ago

      March 2, 2018 at 6:59 pm Hello everybody my name is Cesar Correia from Rhode Island i work on alot of diesels i work for an oil company full time servicing everything they have from diesel vans and gas jobs to large freight liners and kenworts. Lots of diagnosing also. That said i will be doing 90 percent of the work to try and keep my bank account in one piece..Originally the boat had twin 454 crusader 350hp models with 1 3/8 shaft. Originally with 454s 350hp model at …

      Started by:  Cesar

      9 Replies
      March 17, 2018 at 8:01 am Ceasar, You seem to have a great hands-on background in working on engines & equipment, but you are not understanding my responses. 1) The total operating WEIGHT of your finished vessel will be the main factor as to meeting your performance goals vs the HP you have to put into the props. Have you weighted your vessel and thought about what it will weigh after you are finished with the restoration/repower? Every extra pound you add will re…

      Last Post by:  Tony Athens posted: 1 year ago

    • Jersey Dawn Repower

      This topic has 6 replies, has 3 voices, and was last updated by RicM 1 year ago

      February 14, 2018 at 12:33 pm The boat in question is a 36 or 42 jersey dawn. Most 36s come with 3208 cats at 320hp and most 42s have 6-71s TIB 485s. From my research they are 18/19knt boats. My question is it is even possible to get these boats to that 27/28knt cruise with the newer technology? I am also aware that some of the older hulls don’t perform well at higher speeds so any information there would be appreciated as well. Ultimately, I don’t think I would …

      Started by:  Martin Padgett

      6 Replies
      February 16, 2018 at 3:53 pm Did something like this conversation occur over on a while ago? In any case, if that’s the boat you want, and those are the engines you want, go for it. Life is too short to own an ugly boat, or is it Life is too ugly to own a short boat? Something like that, in any case, keep us informed about your quest. I for one would very much like to hear more about this project. Believe me, I spent many hours pondering the same questi…

      Last Post by:  RicM posted: 1 year ago

    • 3.9 stern drive repower?

      This topic has 2 replies, has 2 voices, and was last updated by Paul Harper 1 year ago

      December 28, 2017 at 11:51 am We inherited a 2958 Bayliner last year with twin 350’s & omc Cobra’s. After throwing some time into it, we have decided it needs repowered with engines & drives. The beam is 10.5 making the 350’s very difficult to work on. I work in heavy equipment repair & hate spark plugs. My neighbor at the marina has a 2001 sea sport with twin 3.9’s and Volvo drives, was wondering if this is a option? Thanks for any advic…

      Started by:  Paul Harper

      2 Replies
      December 29, 2017 at 6:08 pm Thanks Tony, we will probably fix what’s in it and use the boat for awhile till something pops up that has a good diesel package. Alot of nice boats out there with really outdated engines installed, hopefully that changes in the next few years. Paul. 1989 Bayliner 2958 Avanti.

      Last Post by:  Paul Harper posted: 1 year ago

    • Repowering a Baja

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 1 year ago

      October 12, 2017 at 6:34 am Let me preface this by saying I have not purchased any boat to do this in yet, this is just a really wild idea in my mind that I really want to make happen, and would like some input as to what your thoughts or concerns would be. I am looking at getting a 26-30 foot Baja Sport powerboat if you will, going to get one with a 454 BBC or bigger in it with a Bravo drive to it at minimum. Now I have always been a diesel guy and would love to do a dro…

      Started by:  Bryan Pence

      1 Reply
      November 16, 2017 at 9:59 pm I guess this is another one that got missed.. Sorry.. Before I get into the “has anyone done this” , (I have) let me ask you this……………..Do you have a general “budget” for such a project and do you have a general sketch or some pictures of what you have now vs, what you want to end up with.. That would make it a lot easier to comment effectively.. Tony Tony Athens Seaboard Founder Go here fo…

      Last Post by:  Tony Athens posted: 1 year ago

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