# Sterntube-less ship concept **URL:** \ **Category:** Marine Engineering\ **Created:** [December 6, 2023, 10:41pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748 "2023-12-06T22:41:47Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![ombugge](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/ombugge/32/11217_2.png) [@ombugge](https://forum.gcaptain.com/u/ombugge)\ **Post date:** [December 6, 2023, 10:41pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/1 "2023-12-06T22:41:47Z")
Thordon Bearings And Wärtsilä Launch Blue Ocean Alliance To Promote Sterntube-Less Ship Concept: > **[Thordon Bearings And Wärtsilä Launch Blue Ocean Alliance To Promote...](https://www.hellenicshippingnews.com/thordon-bearings-and-wartsila-launch-blue-ocean-alliance-to-promote-sterntube-less-ship-concept/)** ---
**Author:** ![jimrr](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/jimrr/32/38358_2.png) [@jimrr](https://forum.gcaptain.com/u/jimrr)\ **Post date:** [December 11, 2023, 5:35pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/2 "2023-12-11T17:35:55Z")
i was kinda hoping for a illustration, didn’t read it all. ---
**Author:** ![Chief\_Seadog](https://avatars.discourse-cdn.com/v4/letter/c/67e7ee/32.png) [@Chief\_Seadog](https://forum.gcaptain.com/u/Chief_Seadog)\ **Post date:** [December 11, 2023, 5:53pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/3 "2023-12-11T17:53:22Z")
I guess it is a matter of semantics as far as what one would consider a “stern tube”. > **[ABS AIP for "Sterntube-less" Ship](https://www.maritimepropulsion.com/news/abs-aip-for-sterntube-597179)** > > Thordon Bearings said ABS issued an Approval in Principle to the “sterntube-less ship” concept developed in cooperation with the… ---
**Author:** ![jimrr](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/jimrr/32/38358_2.png) [@jimrr](https://forum.gcaptain.com/u/jimrr)\ **Post date:** [December 14, 2023, 4:05pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/4 "2023-12-14T16:05:37Z")
i kinda like having that ‘‘space’’ between me and the screws!!! ---
**Author:** ![Steamer](https://avatars.discourse-cdn.com/v4/letter/s/3d9bf3/32.png) [@Steamer](https://forum.gcaptain.com/u/Steamer)\ **Post date:** [December 31, 2023, 5:15pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/5 "2023-12-31T17:15:53Z")
I thought they must have developed a magnetic through-hull drive system or something equally exotic. ---
**Author:** ![hopperdredgbill](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/hopperdredgbill/32/71580_2.png) [@hopperdredgbill](https://forum.gcaptain.com/u/hopperdredgbill)\ **Post date:** [January 5, 2024, 11:54am UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/6 "2024-01-05T11:54:53Z")
Yes, they are called Z-drives! 🙂 ![SANY0186](https://us1.discourse-cdn.com/flex016/uploads/gcaptain_maritime_forum/original/3X/8/d/8d60a6545a79e7f2452c80c7a4d93c8177ca4a45.jpeg) ---
**Author:** ![jimrr](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/jimrr/32/38358_2.png) [@jimrr](https://forum.gcaptain.com/u/jimrr)\ **Post date:** [January 5, 2024, 3:48pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/7 "2024-01-05T15:48:03Z")
looks ok but how long does it keep the water out? and Steamer: those mag drive things are pretty ok but there appears to be a substantial energy loss with them, not that we care that much but ?, I can’t imagine running something like a prop with mag drive? ---
**Author:** ![ombugge](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/ombugge/32/11217_2.png) [@ombugge](https://forum.gcaptain.com/u/ombugge)\ **Post date:** [January 5, 2024, 4:22pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/8 "2024-01-05T16:22:10Z")
Kongsberg rim-driven thrusters: > **[Permanent Magnet tunnel thruster TT-PM 1600](https://www.kongsberg.com/maritime/products/propulsors-and-propulsion-systems/thrusters/tunnel-thrusters/permanent-magnet-tunnel-thruster-tt-pm/tt-pm-1600/)** > > The Permanent Magnet tunnel thruster is a new addition to the Kongsberg Maritime family of thrusters, building on a completely new approach to thruster design and motor integration. > **[Permanent magnet rim-driven thrusters](https://www.kongsberg.com/kmagazine/2022/5/permanent-magnet-rim-driven-thrusters/)** > > Permanent magnet rim-driven thrusters ---
**Author:** ![Steamer](https://avatars.discourse-cdn.com/v4/letter/s/3d9bf3/32.png) [@Steamer](https://forum.gcaptain.com/u/Steamer)\ **Post date:** [January 5, 2024, 5:40pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/9 "2024-01-05T17:40:47Z")
> [@jimrr](#): > > I can’t imagine running something like a prop with mag drive? Azipods and their cousins do it all the time. All electric motors are mag drives. I was thinking along the lines of zero hull penetrations, no power or azimuthing gear other than conventional rudders or like the old Harbormaster units. ---
**Author:** ![jimrr](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.gcaptain.com/jimrr/32/38358_2.png) [@jimrr](https://forum.gcaptain.com/u/jimrr)\ **Post date:** [January 5, 2024, 5:55pm UTC](https://forum.gcaptain.com/t/sterntube-less-ship-concept/67748/10 "2024-01-05T17:55:31Z")
well steamer, it’s been a while. My first experience with mag drive was with small (less than around 50 hp) pumps but at the time the loss was such we were told they couldn’t make them bigger at the time. of course all stuff aboard is 3 phase. they were good to have on macerator pumps !!