The same and/or better efficiency like old soviet hydrofoils ("Raketa")?

Discussion in 'Powerboats' started by S V, Nov 15, 2020.

  1. S V
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    S V Junior Member

    I have understood your points about engines fully.
    The question now is: are there hull forms, except another but more optimised pure hydrofoil, which will get very similar or better fuel efficiency in river going ship in the same (30-35kts) speed range?
     
  2. baeckmo
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    baeckmo Hydrodynamics

    There is simply no other hull shape or form that comes even close to the foilers regarding fuel efficiency in this application. Speed, passenger capacity, operating depth and range plus low wash, are main design driving requirements. Air-cushion sidewall catamarans with waterjets can operate in less depth but are less efficient and the skirts need constant care. As I said in my earlier note, if you are serious about this, contact the Alexeijev Hydrofoil Design Bureau, they have updated and redesigned their rivergoing designs and include modern engine choices.
     
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  3. S V
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    S V Junior Member

    Thank you. This is what I was afraid of.
    Regarding AHDB, no, they havent done anything, except only cosmetically renewing old Polesje type hydrofoils which are more or less inferior to Raketa in many aspects and made just 2 units of them. Another type, Kometa, is only cosmetic renewal of the old one, but it is sea-coastal hydorfoil, which is huge in size and draft. The building of 2 Polesje-Valdai ships total took 6 years, the planing 20+. I can read russian, so I have read everything there is on the web. The wing is the same, so it took them 30+ years to basically renew the operations. If you look at official or semi-official info they are discrepancies about those ships even in the official AHDB released info. Other designs are purelly theoretical or experimental. Also, doing business with russians is almost imposible in my case because of other reasons not realated to shipping industry.
     
    Last edited: Nov 21, 2020
  4. baeckmo
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    baeckmo Hydrodynamics

    Yup, considering the political situation in the Baltic and east Europe region, that statement is no surprise........! This then becomes part of the SOR, and you have to look for the closest alternative. What comes up in my mind in terms of actually built and proven vessels is then the Vosper Hovermarine HM 216 or its slightly bigger sibling the HM 218. It is a sidewall ("catamaran") hovercraft aka SES, designed and built in the 1980:ies. you can find info on the web. I know that the Austrian "Erste Donau Dampfschiffahrts Gesellschaft" had at least one operating in commuter traffic on the Danube between Vienna and Budapest.

    As noted before, there is some extra maintenance for the skirt, and the fuel costs are slightly higher than for the shoal draft foilers, but it does come out fairly well in overall earning capacity comparison. The DDSG could certainly come up with relevant info on that. The problem with the HM vessels are the rather deep propellers, but I could imagine a change to waterjets, provided great care with dimensioning to avoid cavitation at hump speed is applied. Now, with Britain leaving the EU, maybe there could be another "political or trade ban" added to the SOR........ Whether there is a HM laying idle somewhere, or a licence for a newbuilding is possible is yet another question, but technically it works fine.
     
    Last edited: Nov 21, 2020
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    Is "wash" a consideration ? Obviously single engine is allowable, as the hydrofoil referenced is a single engined vessel, The only way to beat the conundrum apart from the foiling, is super-light construction as in with infused composite panels, to get the weight right down, in a monohull with one engine, and a hull form that can reduce wetted area effectively. Given the fairly high cruise speed, aerodynamic penetration should be under the microscope as well. With the boat not needing to traverse ruffled water, then it should be easier to reduce weight. The worst thing it might encounter is a log in the water, and that no doubt would require attention to making sure it does not sink the boat. That boat I posted that was a kind of barge, had disadvantages a purely passenger boat does not have, like needing a strong deck structure to support heavy loads, etc. In a passenger boat, it should be possible to cut weight drastically, with the right materials.
     
  6. S V
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    S V Junior Member

    I can find some info about HM 216, but not related to "Erste Donau Dampfschiffahrts Gesellschaft". Not much actually.

    Raketa is literally at least 50 years old - I mean any of the actual specimen which is manufactured will be 50 years old. And then we are talking about the... at least 40 year old SES. This is a bit weird, or is it only for me? No offence.

    It does not look very good: more fuel, more maintenance, extra engine or gearbox/clutch. Yep, on the positive side, you may win another 10-20cm of draft or even more in case of waterjet which translates into possibility of new route. Somehow I feel that shirt maintenance is not a once-in-season thing, and not fully predictable, which may distrub your schedule during already short season. Also, I have no idea what ship performance will be if there is a loss of shirt integrity (not due to crew error).

    DDSG web shows some of the fleet: Donau-Schiffahrt.at - Fahrgastschiffe http://donau-schiffahrt.at/schiffe/fahrgastschiffe/index_1.html - there are mentioned Twin City Liner v1, Meteor, Voskhod, but no SES ships. If the tech specs are real, hp/person ration of TCL v1 looks not bad at all, and it is simple slender catamaran.

    No I havent traveled in any SES ship...

    Aquisition and taxing may be another Brexit related issue. But if we are taking about the actual hull, then it may be corroding somewhere in EU, it is not an issue then.

    Yes, wash is consideration, but dont know how important. Have no idea about river regulations, but if the new ship's wash is smaller than "older" one it is ok then. I want to clarify - am not against pure hydrofoils, but in this case there are too many problems related to tehcnology itself and situation at hand, such as:
    1. Too complex (pricey!)
    2. Not much ship models on the market - Raketa, Voskhod, Polesje. All 3 of them are similar. Do not know any other rivergoing hydrofoils. Is you know any - I will be glad to hear! On the plus side, those models are more or less acceptable. Raketa has nice stern lounge, Voskhod is the most cost effective, Polesje is suitable for the most shallow rivers. All of them single engines with complex wings but simple systems apart that.
    3. Even if they are acceptable, we are talking about the boats, which are not made anymore. They are designed 70-50 years ago, and most of them are turning to dust somewhere in Siberia.
    I could continue this list on and on.

    That barge you posted is no doubt a very very nice ship, very suitable for archipelago of rocks it is operating. Finland is a rich country, with many islands, premium fast service may have a market there. I somehow doubt that it has good fuel eeficiency.
    Displacement: 14.8T
    Engines 1150Hp
    Speed 34Kn (top or cruise???)
    2x waterjets
    No numbers about fuel consumption per h
    Numbers from manufacturer about similar boat:
    Kewatec Work 1500 - Kewatec Aluboat https://kewatec.com/boats/kewatec-work-1500-aluminium-working-boat/
    Displacement: 11T
    Engines 640Hp
    Speed 34Kn (top or cruise???)
    2x props
    No numbers about fuel consumption per h

    60 passengers + structure for them + seats, toilet, their hand cargo, fresh and used water etc. That is not light. Ship of this type loaded with such amount will be not not that much lighter than Raketa.
    If we assume the ship of this type fully loaded is 20T displacement, what is the most lightweight we can squeeze, how much Hp is needed for 34Kn with props and with jets?
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    Obviously being across all regulatory requirements for the area, and the type of operation intended, would be the first order of business, everything else would proceed from that. I certainly wasn't pointing to that barge as the exact vessel , but as an example that a monohull planing hull with jet drive can approach the requirements you mentioned, but it would need to be carefully thought out to keep weight and wetted surface area down as far as possible, but again the vessel itself, as a commercial operation with people's lives at stake, might have to jump through regulatory hoops that make that difficult. I guess the best hope there, is that it is strictly for smooth water use, which could make life easier meeting survey requirements. It may be the case that more than one engine is mandated, although the hydrofoil vessel you mention seems exempt from that.
     
  8. S V
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    S V Junior Member

    Checked one prticular route: no there are none "additional" requirements for the boat wake or the people safety. General EU rules apply, there are no rule about multiple engines. 2 types of the above mentioned soviet hydrofoils operate there. Their wash is not the biggest, but it is substantial. Smaller recreational yacht with big deadrise makes a lot more. It is river route.

    If you or someone have any examples of similar level efficiency 50-70 passenger boat, especially simple planning monohull - would like to know.
    ~34kt, 160-170 diesel liters/hour, 56 passengers. Raketa is ~25t full load, with 56 passengers, Voskhod with ~6-12 more seats is ~28t.
    Lets say that monohull with the acceptable building techniques it will be no lighter that 21t at full load.
     
  9. S V
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    S V Junior Member



    What is the approximate deadweight of this ship?
    ~1,8L/km of fuel at 30 knots
     
  10. Nidza
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    Nidza Junior Member

    Hmm, hydrodynamics is not at all my topic, but I am curious...

    Would it be possible to implement this already known (in different applications) air bubbling concept, "ASV" as it is called in the video in previous message by SV, with the hydrofoils? With my ignorant point of view, the assumption/hypothesis is that it would be required (much?) less power to achieve air bubbling on the smaller foil surface compared to the greater hull surface (of foil-less boat) and that it would further decrease the resistance of the foil / increase the efficiency.

    I mean the advantage of using foils is already quite an old topic, so is the air bubbling decreasing the resistance, so it would be interesting to see if this could potentially even further increase the foils performance. As already mentioned earlier in the thread, implementation of foil control mechanisms is better/easier today, but as I have understood, "not much" is done on the foils (I have put quotation marks since as an engineer I am aware that not much can take ears of research and hard work).

    Of course, I am sure there are millions of questions to this, e.g. how to provide the air from the boat to the foil, would it affect the steering and the flow to the propeller(s), would the foils have to be thicker to not be bent at speeds, etc., but I find it fun and I would like to see this one, maybe even on some RC boat for the beginning. Or maybe someone could share something if there is already something like that? I would like to see/find out this.

    By the way, these Raketas were also present in my country on the Danube long time ago, there are still some corroding as static restaurants and people are still nostalgic remembering them. I have also read on some forums there, that beside fuel, these were using around 200 liters of oil, but not sure if for 200km single trip or 400km round trip. Now, was this due to old technology or unmaintained engines, that I do not know.
     

  11. Rurudyne
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    Rurudyne Senior Member

    Nidza, I'm sure some of this has already been covered.

    Still some quick comments:

    If you put air bubbles / sheet of air over the foil it might have the effect of increasing lift. I don't see forced cavitation for any control surfaces on a foil being a problem unless the bubble layer is actually sticking to it, I don't know if that would happen or not.

    If you had the bubbles under the foil you would decrease your lift and possibly cause cavitation at the trailing edge.

    However air trapped under the supporting struts if they give no lift and are substantial may be of value. Likewise bleeding bubbles from the strut sides where they won't cause a reduction in lift may be of use but you'd probably need to have some sort of undulating surface designed to help retain the bubble layer.

    All this sounds very complicated on top of the struts and foils; however, a burst of air under the hull for the moments before lift off might be something worthwhile. It would only need intermittent operation rather than continuous as with an ASV ... meaning it could be simpler and lighter, something of value to a hydrofoil. Moreover testing would be lest costly. There are people powered hydrofoils after all, you could fit one with some compressed air that you release into an ASV like cavity just as you're getting up to speed and compare things like carrying capacity where you actually achieve lift or variations in the power needed to achieve lift. The difference may not be worth the effort but you wouldn't be out a fortune and you might end up with a discussion piece among the HPV crowd.
     
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