Mess Deck: General Section => Full Scale Ships => Topic started by: roycv on April 15, 2018, 09:01:14 am
Title: Future of ship propulsion
Post by: roycv on April 15, 2018, 09:01:14 am
Hi all, I have just read this treatise from Royal Academy of Engineering. Although dated 2013 it covers everything to do with full size ships and propulsion. I found it a fascinating read.
Title: Re: Future of ship propulsion
Post by: TugCowboy on April 15, 2018, 03:40:29 pm
Fascinating stuff there, thanks for sharing!
Title: Re: Future of ship propulsion
Post by: roycv on April 15, 2018, 06:08:47 pm
Hi Davie Tait, I was not impressed by the KRISO video, especially their choice of ships, what was the SS Great Britain doing there? Then I read the remarks, seems neither was anyone else! I came across a parallel 2 pod system with one pod using a contra rotating propeller which claims to help eliminate rotational losses. regards Roy
Title: Re: Future of ship propulsion
Post by: Plastic - RIP on April 15, 2018, 06:55:32 pm
I didn't see any mention of the $$$ that the US Navy are throwing at small (5MW-ish) fusion plant research.
And they've just applied for a patent (https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=2014301519&KC=&FT=E&locale=en_EP) relating to the magnetic field systems in their test reactor. Clearly work is being done, money spent. I sense a degree of confidence which could pan out rather well utterly alter all our futures for the better. ;)
Andy
Title: Re: Future of ship propulsion
Post by: DavieTait on April 15, 2018, 08:32:15 pm
Hi Davie Tait, I was not impressed by the KRISO video, especially their choice of ships, what was the SS Great Britain doing there? Then I read the remarks, seems neither was anyone else! I came across a parallel 2 pod system with one pod using a contra rotating propeller which claims to help eliminate rotational losses. regards Roy
The props they are putting onto real merchant ships do work Roy , read various articles about them that show they are getting almost the same efficiency gains as a kort nozzle's do but without the added drag the nozzle causes so for free running they save more fuel
Hyundai Heavy Industries in South Korea are fitting their own version
The professor in Back to the future two may well be right when he brings his bucket sized 'Mr Fusion' back from the future.
I hope that Fusion will work as it is clean, and miniaturisation will indeed only help us get cleaner.
It's not that clean - the whole device gets massively Neutron irradiated and the breeder blankets need to be processed to generate more fuel. They are a huge maintenance problem - the internal materials still do not exist to survive the fusion environment.
Title: Re: Future of ship propulsion
Post by: roycv on April 15, 2018, 09:06:06 pm
Hi Davie, thanks for putting up the prop video, the props look almost like they continue the propeller blades down to a pin point. I still was not impressed with the rather unspecific KRIS video. I think stating % gains does help one put it into context. With the previous generation of Americas cup yachts some were using the pimpled golf ball surface which was just 0,01 % speed improvement but over several miles it meant several boat lengths difference. It does seem surprising that the whole thing is still showing ways to improve propulsion. kind regards, Roy
Title: Re: Future of ship propulsion
Post by: Akira on April 15, 2018, 09:13:04 pm
What we don't know will fill a big basket. I thought that pump-jets, such as used on US and UK subs were a relatively new system. Not so as this 1959 photo shows them being tested on a US destroyer:
Title: Re: Future of ship propulsion
Post by: DavieTait on April 15, 2018, 09:17:29 pm
I believe the second set of blades on the spinner of the prop help to capture the energy lost at the root of the main blades and thats what gives them the big increase in efficiency certainly something I've seen on some diesel submarine prop photos
(https://1.bp.blogspot.com/-anqVnE-nvQw/Vz_lLC4x5dI/AAAAAAAAIz4/OIhK9CpflNk-8xPN_nBcXk5Z3cb2QUUlACKgB/w1200-h630-p-k-no-nu/Type%2B212A%2Bpropeller%2B2%2Bshots%2Bon%2BJapanese%2Bopen%2Bwebsite.jpg) Variation on a German Type 212A sub ( their newest type )
Title: Re: Future of ship propulsion
Post by: Martin (Admin) on April 16, 2018, 03:24:57 am
How about inflatable mast / wing sail?!
Title: Re: Future of ship propulsion
Post by: Brian60 on April 16, 2018, 11:50:53 am
I believe the second set of blades on the spinner of the prop help to capture the energy lost at the root of the main blades and thats what gives them the big increase in efficiency certainly something I've seen on some diesel submarine prop photos
When the QE11 was refitted with diesels they also fitted new props and what was referred to as "vane wheels" behind the prop. If I remember correctly, these were quite long, but relatively thin blades, which "free wheeled" in the wash of the prop. These did indeed increase the efficiency and increased her speed at the same time, around 5 knots or so I think it was. All worked well until the "vanes" broke off during trials In the North Sea! LB
Title: Re: Future of ship propulsion
Post by: tony52 on April 16, 2018, 02:21:12 pm
Paddle driven vessels are also undergoing changes. The "Sura" (of 2010) on the Russian river Volga has angled stern paddles hydraulically driven (which can be seen in the second photograph in the link). "Sura" is powered by conventional diesel fuel or biofuel. Some years ago I came across a report about her design, but can no longer locate it. The report mentioned the angled paddle wheels which were very fuel efficient and eliminated the need for dry-docking when undergoing maintenance.
That is interesting about the Neutrons and reprocessing of blankets etc Plastic. I must read up more about it.
I have friends working on JET & MAST projects at Culham.
From the Eurofusion site:
"The blanket is a layer surrounding the vessel in a fusion powerplant. It will absorb the energy from the fusion neutrons produced in the plasma, boiling water via a heat exchanger, which will be used to drive a steam turbine and produce electricity. The proposal is to embed lithium in the blanket, because that will react with the neutron to produce tritium, which is a fuel for the plasma, along with deuterium. The breeding of tritium occurs through the reaction Li6 + neutron becomes He4 + tritium. This would be advantageous because tritium is radioactive, with a short half-life, and so is difficult and expensive to obtain – it would be far more sensible to manufacture it onsite as a by-product of the fusion process."
Title: Re: Future of ship propulsion
Post by: tonyH on April 18, 2018, 07:47:51 pm
Just to add another aspect, this is the Thornycroft screw turbine from about 1890. It was a possible version for Turbinia but found a more suitable home on vessels for shallow water use. The small prop ahead of the turbine bit was for going aft because the main propulsion was only one way! Seems to be about 70 years ahead of the game ok2