This forum contains 25 topics and 106 replies, and was last updated by  Danny Sunkel 4 weeks ago.

Viewing 20 topics - 1 through 20 (of 25 total)
    • Cummins Marine Forum Topics
    • 86 Bertram 35 repower options

      This topic has 2 replies, has 2 voices, and was last updated by Danny Sunkel 4 weeks 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. danny@gfab.co.nz

      Last Post by:  Danny Sunkel posted: 4 weeks ago

    • Thinking of re-powering from Cat to Cummins

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 4 weeks 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: https://www.sbmar.com/tonys-tips/

      Last Post by:  Tony Athens posted: 4 weeks ago

    • Cummins repower

      This topic has 2 replies, has 3 voices, and was last updated by Bill Desmarais 4 weeks 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: 4 weeks ago

    • Repower Question

      This topic has 6 replies, has 5 voices, and was last updated by Rick Smith 1 month 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: 1 month ago

    • Re-Powering 1999 26' Shamrock Express

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

    • Unspported Shaft Length

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 4 months 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: https://www.sbmar.com/tonys-tips/

      Last Post by:  Tony Athens posted: 4 months ago

    • Transmission Clearance to Hull

      This topic has 2 replies, has 2 voices, and was last updated by Mike P 5 months 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: 5 months ago

    • 1997 Bertram 36 Repower

      This topic has 13 replies, has 8 voices, and was last updated by Tim Schantz 5 months 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: 5 months ago

    • Possible shamrock repower

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 5 months 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: 5 months ago

    • Possible shamrock repower

      This topic has 1 reply, has 2 voices, and was last updated by john 6 months 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 https://forum.classicshamrock.net/ Great project though goo…

      Last Post by:  john posted: 6 months ago

    • Repowering 1990 luhrs 320

      This topic has 9 replies, has 3 voices, and was last updated by Tony Athens 7 months 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: 7 months ago

    • Repower 35 Henriques Pilothouse

      This topic has 8 replies, has 3 voices, and was last updated by Tony Athens 7 months 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


      8 Replies
      March 6, 2018 at 7:01 pm From your answer to my post, I am not sure if you understood what points I was trying to make.. May I ask where you are located? Can you post some good pics of the 8.3 as currently installed in you vessel so we all can get an idea what what you are dealing with? Maybe a “smaller” engine will allow better service accessibility and that is part of the underlying issue or issues? But regardless, these engine are far from “ap…

      Last Post by:  Tony Athens posted: 7 months ago

    • Jersey Dawn Repower

      This topic has 6 replies, has 3 voices, and was last updated by RicM 8 months 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 BoatDiesel.com 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: 8 months ago

    • 3.9 stern drive repower?

      This topic has 2 replies, has 2 voices, and was last updated by Paul Harper 9 months 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: 9 months ago

    • Repowering a Baja

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 11 months 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: 11 months ago

    • CAT 3126 420 to Cummins 6CTA 430

      This topic has 6 replies, has 3 voices, and was last updated by Tony Athens 11 months ago

      October 25, 2017 at 8:26 am Posting this for a guy on down east boat forum. I’ve asked him to join……”hell it’s free” !!!!! “hey bill I know your a cummins guy and are very knowledgeable in this are I’m thinking for down the road I have a cat 3126B 420hp now with a td2.5:1 gear if I put in a recon 6cta 430hp could I use the same gear the cat turns 2800 wot the cummins 2600 wot” The boat is a beautiful 36 H&H down east lo…

      Started by:  Bill Desmarais


      6 Replies
      October 29, 2017 at 12:49 pm Propped right, the 6CTA 8.3 will turn at least 2750 and can run all day at 2400 RPM.. If you are working the motor super easy, just add 1-2″ of pitch to get the R’s down to 2200 or so to get your happy vessel speed. Don’t confuse MINIMUM rated RPM or test cell data with how this engine really likes to be propped in the field under real ocean/working conditions. . Tony Tony Athens Seaboard Founder Go here for the latest stuf…

      Last Post by:  Tony Athens posted: 11 months ago

    • Jersey Sportfish Repower

      This topic has 8 replies, has 5 voices, and was last updated by leonaj99 11 months ago

      October 9, 2017 at 6:38 pm The boat is a 42′ 1993 Jersey Dawn III sport fish. The engines are 6-71 TIB’s, 485HP, that have about 1000 hours on them since full rebuilds. They run fine, but they are noisy, dirty, and smelly. It’s a great boat, and my wife and I both love the interior layout and it’s livability. We are now retired and are contemplating the options of running this boat back and forth from RI to FL vs staging it down there and buying …

      Started by:  RicM


      8 Replies
      October 22, 2017 at 8:16 am Rick good luck in your repower and in making the tough decisions. I just want to emphasize Tony’s comments regarding sub system upgrades/improvements. Having done a single engine repower myself in the past and having done most of it myself I found an awful lot to do as soon as the old engine was out. Old thru hulls? Now I have good access so time to install new ones. Old water system plumbing? Gone and a new system installed with proper a…

      Last Post by:  leonaj99 posted: 11 months ago

    • Repower Options ?

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

      September 1, 2017 at 7:09 am I’m posting this question for a boat owner friend who has a 32 H&H (Osmond Beal down east) lobster boat. Right now the boat is powered by a 1999 Isuzu 6 cyl. Model A-6BG1T 230 hp rated @ 2500 rpms. The engine is keel cooled with dry stack exhaust. Tranny is a ZF63A 2:1 gear, 1.5” shaft with 24X22 #3 cup prop. Weight is a guess @ 12,000 lbs +-. Owner stated the boat is “heavy” for the sea trial. I sea trialed the boat this past week …

      Started by:  Bill Desmarais


      6 Replies
      September 3, 2017 at 8:07 am Rob, I’m confident the repower of this older 32 H&H will be no more than a ReCon engine. 25 Terry Jason down east, 370 6BTA CPL 2008 ZF63A gear, 1.75" shaft, 20X19 DQX

      Last Post by:  Bill Desmarais posted: 1 year ago

    • QSC propping to engine load

      This topic has 2 replies, has 2 voices, and was last updated by Luke Nelson 1 year ago

      June 14, 2017 at 6:03 pm Hi Guys, I am after some input on engine load to propping. I have just swapped out a pair of 3208’s to qsc 540’s. I think I may be close but everyone wants more speed if they can have it. The props were calculated on the 490 hp curve to keep within the shaft limits for survey( I am using marinex hs22 2.25). I can post the full numbers but at 2400rpm I get 19.5 knots @ 120 LPH and 52% load. At 2600 I get 22 knots and 74%. The engine …

      Started by:  Luke Nelson


      2 Replies
      June 25, 2017 at 2:56 am Thanks Tony, It makes sense when you say it like that. The sea water sides are on my list to strip and clean. thanks Luke Attachments:You must be logged in to access attached files.

      Last Post by:  Luke Nelson posted: 1 year ago

    • Repower 34' Libby with Cummins QSB 5.9 480

      This topic has 2 replies, has 2 voices, and was last updated by John Albaum 1 year ago

      June 14, 2017 at 9:14 am I’m looking to repower my 34′ lobster boat(Libby 34×13). I have a Deere 6068SFM50 rated at 265hp with a ZF280 at 2:1 to a 2″ shaft spinning a 24×25 wheel at the moment. The engine I’m looking at is a very low hour QSB 5.9 at 480hp. I know the engine will fit and my gear and shaft will handle the horsepower. My questions revolve around the exhaust and the power steering pump that is already on the engine. Th…

      Started by:  John Albaum


      2 Replies
      June 14, 2017 at 10:08 pm Thanks for the reply. With the Deere I can make a little over 19kts at WOT and about 13.5gph, and that’s right were I would like to cruise, so I feel like that wouldn’t be too hard for the 480 to do. I’ve read they can cruise comfortably at 17ish gph. I’d be doing 300-400 hrs per year so not too much. I’ve attached a picture of the engine with the power steering pump attached. I don’t know if this is a Cu…

      Last Post by:  John Albaum posted: 1 year ago

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