This forum contains 35 topics and 138 replies, and was last updated by  Tony Athens 1 month ago.

Viewing 20 topics - 1 through 20 (of 35 total)
    • Cummins Marine Forum Topics
    • Repower Skipjack25

      This topic has 3 replies, has 4 voices, and was last updated by Tony Athens 1 month ago

      September 13, 2019 at 8:53 am Hi, new to this site. I have an older Skipjack 25 that I want to repower with a Cummins Diesel. If you know the boat can I get a ball park estimate of that it will cost. I will be needing a new duel prop outdrive as well. Currently its powered by a marine power 5.7 with a volvo 290 out drive Thanks Tony Skipjack 25 (restore) Attachments:You must be logged in to access attached files.

      Started by:  TC


      3 Replies
      September 16, 2019 at 3:59 am If you have a $70-100K, can find a new Yanmar 4LHA, have a really good shop at your disposal, and put in a year + of free labor, you could do something like this………………. As to a Cummins, no-go for that hull.. 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/ Attachments:You must be logged in to access attached files.

      Last Post by:  Tony Athens posted: 1 month ago

    • Shooter the 40 knot Bertram 31

      This topic has 2 replies, has 2 voices, and was last updated by david h witty 2 months ago

      August 12, 2019 at 7:31 am Was wondering if there are any updates on Shooter? she was cruising at 32 knots with Yanmar 6ly2 STP’s and wondered if the engines had lasted . was also interested in details such as EGT,boost, and RPM at that cruise speed. I have a contender 35 with 25 y/o 6ly(m) ute’ s which is reason for my interest. thanks!

      Started by:  david h witty


      2 Replies
      August 16, 2019 at 10:09 am Thank you Tony Am weighing all my options for possible repower.My boat is obviously old and I don’t think worth it to put in brand new engines.For reasons of simplicity and cost should probably stay with mechanical engines.Qsb 5.9 440 would sure be nice though,but are 8 inches taller than my current engines and likely won’t fit. Good to know the 6ly2 can provide the desired performance and last if used in right application and proppe…

      Last Post by:  david h witty posted: 2 months ago

    • Is it worth repowering a 2008 Sabre 42 flybridge with Cummins QSC’s

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

      August 4, 2019 at 11:32 am So I want to buy a Sabre 42 flybridge, I want the planing speed, the look, the quality and the fly. I want one that is a 2008 or older because I do not want pod drives and all newer Sabre’s are pod driven. However the only ones for sale have the Yanmar 6cx-gte or 6ly-etp and I’ve educated myself on those motors to the point that I’m not willing to own them but I believe I could buy the boat for $300-350k. Alternatively I could buy the sist…

      Started by:  Thomas Riley


      1 Reply
      August 4, 2019 at 3:28 pm Simple answer to a simple question–NO you will not get your $$ back unless you can buy the boat for under $50K.. What you will get if the repower is done “100% Seaboard Right” is a very usable boat that would meet you needs for years to come…. 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: 2 months ago

    • Completed Repower of 38 ft Commander

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

      August 4, 2019 at 5:25 am Just completed the repower of my 1965 38ft Flybridge with rebuilt 6BTA 370’s with new ZF220A’s 1.75:1 Had Tony and guys build up a new exhaust system and fitted some of the SB engine upgrades and new custom engine and transmission mounts. With the old Detroit 8.2L Turbos with 2:1 TD 502’s top end at 3000 was 25 mph with cruise at 18 – 21 mph depending on load. Cruise at 2600 RPM burned 18 G/H. Propped with 3 blade bronze 22X20 on 1…

      Started by:  pwrobert


      1 Reply
      August 4, 2019 at 11:01 am Getting better than 1:1 on plane in a boat that size tells me “ya done all 100% right”……………. Good job…. Post some install pics to helps other.. Also, and super important to stress is that letting these types of engines spin up, and spin-up easily to 100-150 RPM above their minimum rated speed…………… Why typical props shops seem to have a such a hard time understanding …

      Last Post by:  Tony Athens posted: 2 months ago

    • 86 Bertram 35 repower options

      This topic has 3 replies, has 3 voices, and was last updated by pwrobert 2 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


      3 Replies
      August 4, 2019 at 8:21 am I just posted a note about re-powering my 38 – going from 410 HP to 720 HP and I increased top end, reduced cruise RPM with the new setup which allowed for the less wear on engines and still better performance and with slightly reduced fuel consumption. My thoughts are that after considering possible engine packages . Pick a series that fits dimensionally and go with the highest HP in the series. You can always throttle back. Usually the w…

      Last Post by:  pwrobert posted: 2 months ago

    • Repowering a 43' Delta Marine with 380 hp 5.9 qsb Cummins ??

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

      July 15, 2019 at 8:17 pm I’m Thinking of re-powering my 43 Delta Marine with a pair of 380 hp 5.9 qsb Cummins. Wondering if anyone is running these in their 43 Delta’s? If so, what kind of speed/fuel economy would I expect? And if you would have any thoughts on wether it would be a large enough displacement engine to last a few thousand hours of commercial use? Currently the boat has 210 hp 3208 cats. Cruise is 12 knots, WOT is 15 knots. Thanks!

      Started by:  Caleb Cameron


      1 Reply
      July 27, 2019 at 9:04 am Caleb, I have not repowered a 43 Delta with QSB 5.9’s, but for sure they will do you right if set up proper from Day 1.. I have plenty of them out there with well over 10,000 hours of them in commercial use.. Earlier this year I removed a pair from this vessel ( Aloha Spirit — https://www.channelislandssportfishing.com/aloha-spirit-sportfishing ) with right at 30,000 hours on them (all original) .. Still running daily but he got a …

      Last Post by:  Tony Athens posted: 2 months ago

    • Shaft seal water feed

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

      July 5, 2019 at 9:33 am Hello guys! I did replace shaft seal for new one,similar like PSS system,and have some worries about seawater cooling for shaft seal. It is a sailboat,it has small Yanmar engine in it,and i did found for me perfect spot for connecting hose to shaft seal,and did put also small valve on this pipe,so i can close it when replacing impeller or other works. Connection is on pipe which goes from seawater pump to heat exchanger. But engine lies just bit…

      Started by:  Matija


      4 Replies
      July 6, 2019 at 5:48 am This is not a knock off,this company exists from end of 19 century in Europe,good quality parts,not copy nor nothing. Guardianage company wants that i install water feed anyway,i will go with Y-piece from syphone breaker,easiest way to do it probably,so i dont waste more time.

      Last Post by:  Matija posted: 3 months ago

    • Repower 35 Henriques Pilothouse

      This topic has 9 replies, has 3 voices, and was last updated by finalee2005 5 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


      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: 5 months 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 5 months 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: 5 months ago

    • 35 T Jason Repower

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

    • installing 6bta w/ 220a

      This topic has 1 reply, has 2 voices, and was last updated by donald roth 6 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: 6 months ago

    • Propeller Cupping – 38 Bayliner

      This topic has 10 replies, has 3 voices, and was last updated by Nick 6 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: 6 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 7 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: 7 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 1 year 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: 1 year ago

    • Cummins repower

      This topic has 2 replies, has 3 voices, and was last updated by Bill Desmarais 1 year 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: 1 year ago

    • Repower Question

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

    • Re-Powering 1999 26' Shamrock Express

      This topic has 4 replies, has 3 voices, and was last updated by john 1 year 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: 1 year 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: https://www.sbmar.com/tonys-tips/

      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

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