Semi Submersible Sailboat Hybrid

Discussion in 'Boat Design' started by NautiPhillip, Aug 31, 2019.

  1. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,428
    Likes: 51, Points: 48, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    HMS Seal (N37) - Wikipedia https://en.wikipedia.org/wiki/HMS_Seal_(N37)#Loss_in_Kattegat

    Was a Mine Laying sub that hit a mine. Keel was dropped after being stuck on the bottom and partly flooded. Says the "Drop Keel" was 11 tons which doesn't seem like much on a 2,000+ ton sub, and its drop supposedly prevented re-submerging even with a partly flooded sub, so maybe "11 tons" is a misprint. IIRC in addition to the battery banks typical U-boat had a solid lead keel equal to about 1/3 of total displacement.

    I've always wondered why normal modern sailboats don't have provision to carry a row/stack of standard off the shelf Deep Cycle batteries. I was at a MacGregor dealership in N SF Bay and they were adding 2 and 3 extra batteries as a pretty common mod for new customer's boats. The new MacGregor does have a 300lb rather flat lead "keel" in the bow. I'd carve out some of that lead and replace with 4-6 batteries. Bonus: in an emergency you could jettison the batts, or stuff them in a duffel bag, tie with rope and create an emergency 2-300lb anchor (lol).
     
    NautiPhillip likes this.
  2. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Hi CocoonCruisers, you've covered a lot of ground. Good thoughts all. We are pretty like minded, but you are much better at expressing yourself.

    Please forgive me if I don't address these items right now. I'm working on something that might help to clarify my thoughts. With this, I hope to answer many of these issues and maybe give you some food for thought as well. Wish me luck.
     
  3. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Hey Squidly-Diddly, thanks! I look forward to it. I guess I was wrong about it sounding like maintenance was the culprit. I stand corrected. I love stories like this.
     
  4. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Hi CocoonCruisers, Squidly-Diddly, et al., sorry to take so long responding. I thought it best to back to go back to the beginning so I could show you where this idea started and approximately, where I would like to end up.

    Please pardon the crudeness of my drawings. They are the product of Sketchup Make 2017 which is all I have at this point. But I know it well enough for it to generate basic drawings quickly. I have a few system and detail drawing in progress as I figure this thing out, but the hull should be optimized first and to my intended goals

    These hulls are both 97.5' in length and are 10' in beam yielding a 9.75:1 L/W ratio. This is the L/W ratio of the top boat of the illustration from Covert Shores from my earlier posts that averaged 20+ knots over 2000 nm in the open ocean. That's 2000 nm in a little over 4 days.

    The cylindrical shape for my purposes is one of necessity. However, it does have it's drawbacks which I'm sure you will immediately notice from the drawings.

    The hard chined hull is a simplified and inexpensive fiberglass and plywood knockoff of much more sophisticated DARPA inspired designs adapted to various military craft. I like a lot of things about this version, not the least of which is it's simplicity and economy. However, these are basically 'throwaway' boats, often abandoned after their first use.

    Like the above, my initial concept was a vessel that ran awash in heavy seas. I seek comfort, safety, speed and versatility. My final version should be capable passage-making at respectable speeds under sail, auxiliary power or both.

    I would have a vessel that, if needed, could ride with more freeboard or could completely submerge for long periods at snorkel depth and for limited periods at 4-5 atmospheres or more, depending. That said, running awash under sail, auxiliary power or both, should be considered the main modes of operation.

    A cylinder shape allows for full circumference sealed needle bearings to be recessed flush into the hull. This is to accommodate an external structure that feely rotates approximately 180 degrees around the longitudinal axis of the boat. That structure would support a self-stepping mast and remotely trimmed rigging above and retracting and canting counterweight(s) below. In this way, the exostructure would heel under sail without affecting the attitude of the hull. This is needed for a number of causes, but primarily to optimize the natural orientation of decks, working surfaces, storage, snorkel, etc.

    I want to explore the idea of these systems above and below retracting into fairings to reduce drag or windage as the case may be, to facilitate navigating shallow waters, violent sea states or while operating submerged. I also have played with the ideas of using the retractable counterweight struts as spuds, adding retractable thrusters, a secondary pilot station and even a minisub and/or diver's bay in the bow section; all to support a number of operational applications.

    I realize that different approaches require added layers of complexity. I am a big fan of the KISS theory but functionality is king. I don't mind inexpensive (in a relative sense) but will not trade off quality at the expense of safety or functionality. I don't think that the wheel needs to be reinvented here, but I like off-the-shelf where available and appropriate, a modular approach and critical system redundancy. For instance, I expect auxiliary power to the auxiliary power and massive fuel and battery storage requirements and the ability to jettison mast and rigging or even the entire exostructure should circumstance demand.

    I also don't mind adapting any off-the-shelf product to fit another purpose; like using commercial grade drone electronics to drive an exterior camera orientation and focus while also manipulating the control surfaces in concert with the orientation and thrust of electric outboard motors (perhaps implemented as retractable thrusters). This approach could reduce this type of functionality to a few thousand dollar addition once developed.

    Imagine having a submerged 'hover' ability at a dive or salvage site, full turn-in-boat-length capability or single-handed docking of a 100' vessel into a layalong berth between multimillion dollar yachts while traversing walkways with a drone remote in one hand and a fender, stern, bow or springer line in the other despite complicated current and/or wind conditions.

    I fully realize the 'flip' function might not be a wise choice, ;) but the stationary hover or return to home function might prove indispensable.

    Criticisms, ideas, suggestions and flights of fantasy are welcomed and greatly appreciated.

    CompVSVHulls4.png CompVSVHulls1.png CompVSVHulls2.png CompVSVHulls3.png
     
    Last edited: Sep 16, 2019
  5. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Hey Rumars, kapnD, Deering, would you guys consider sharing your considerable wisdom concerning the above post?
     
  6. Rumars
    Joined: Mar 2013
    Posts: 275
    Likes: 58, Points: 28, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    I don't have any "considerable wisdom" to share. Nevertheless I can ask some questions. How much weight do you need to sink that cylinder to minimal freeboard? How much sail area do you need to move the resulting mass to the desired speed? How will you put that sail area on a mast and how will you support the mast?
     
  7. fallguy
    Joined: Dec 2016
    Posts: 1,984
    Likes: 113, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Just a couple of points from a boat lover.

    1. I would not enjoy the ride. I like to see out and take a look at things. You do have an above water area, but it seems confining as does the entire craft.
    2. It would take quite a bit more power to operate this thing because it is essentially all drag.
    3. Is it a sailboat?
    4. It is certainly not stable. You can do a simple test to check. Take a pencil and a wad of chewing gum and see if you can spin it as designed. It will surely rotate around its main axis. Probably flop over without trying to spin it... Let's say you load it up with a LOT of lead in the bottom. It'd improve, but the expense is the entire ship gets lower and that costs more to propel.

    Just my 2 cents
     
  8. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Hi Rumars and thanks. You get to grade my responses! :D

    I was told that forming 'good questions' was a sign of wisdom, so you seems to qualify. Besides, I've read a number of your posts and I enjoy the way you think.

    About 93 to 94 tons.
    Have not calculated yet. At this early stage, I'm not even sure of construction method or materials.
    I have a few drawings but that is still in a state of flux. I am leaning towards a ketch rig. I am trying to minimize weigh aloft so I'm thinking carbon spars, dyneema stays, shrouds and lines. Still researching sail materials. You have suggestions?
     
  9. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Thanks for your interest fallguy. Welcome aboard. I read your post and I wonder if you read post #19 (<= click here) or any prior to that? I covered a lot of your questions already, but I understand your concerns.

    Thanks. I like that we are starting from common ground.
    Yeah, the 'dark cave' effect. You aren't the first to comment on that. Two to three inch thick acrylic portlights that split the waterline will go a long way towards dispelling that effect. Might be a pretty stunning view in clear water. I'm thinking that the planned shipboard camera system distributed via the ships network may help there too.

    I'm also working out a bridgedeck that would accommodate all hands. The canopy would also be acrylic to give a panoramic view. I'd like to add a stowable tramp across the stern area for lounging in favorable conditions.
    This hull mirrors the 'narco' variant of the DARPA inspired VSV hull design. At 9.14:1 has the near the same L/W ratio of these at 9.75:1. That craft is about 52.5'x5.74' and fully loaded with provisions, crew and cargo for ballast, averaged 20+ knots in open ocean running awash. It made a 2000 nm transit in a hair over 4 days. Theirs was the hard chined hull. I am exploring a tapered cylindrical hull with nearly the same L/W ratio.
    Yup! see details in post #19. (<= click here.)
    Again, already covered in post #19.
    A lot of this stuff I'm still working out. Plus I'm relatively new to this.

    Thanks for sharing first impressions. I would love it if you would critique the points I made in my earlier post. It would help me a lot.

    Seems worth more to me. Thanks again.
     
  10. Rumars
    Joined: Mar 2013
    Posts: 275
    Likes: 58, Points: 28, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    With 93t (how did you calculate that btw.?) and all that drag from the submerged hull we are in J-class yacht territory when it comes to the needed sail area. Installing a mast (or two) will be difficult with a staying base only 10' wide. Plus you need to operate the sails remotely (sail by wire) from the inside.
     
    fallguy likes this.
  11. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    I took the interior volume of the hull shape, converted cubic feet to gallons, multiplied by 4/5th and calculated weight displacement @ 64 lbs per gallon. Am I close? I started with 6197.5056 ft³.

    Whatever the result, it would have to compensate for the entire weight of the vessel including systems, ballast (both static and dynamic) and well, everything including cargo. However, having just been released from the hospital again, I admit; I'm way off my game.
    I haven't worked out the details of the rigging or a sail plan yet. Please remember that the exostructure is independant of the hull, so there is a little room to maneuver as far as base width.

    I have come up with some ways to address remote trim obstacles, but nothing is decided. I'm still spit-balling. Just thought you might like to come along for the ride
     
  12. upchurchmr
    Joined: Feb 2011
    Posts: 2,851
    Likes: 89, Points: 48, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

  13. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,428
    Likes: 51, Points: 48, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    thats mostly because that hull is optimized for fully under water operation and reduction of noise/sonar, and max underwater speed under nuclear power.

    I'd say the late model Nazi U-boats/USS Nautilus type hull is a good compromise for current civilian use.

    PS-IIRC the USS Nautilus suffered from vibration of the "sail"/conning tower at higher underwater speeds.
     
  14. Rumars
    Joined: Mar 2013
    Posts: 275
    Likes: 58, Points: 28, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    I'll recomend doing all the math in metric, it's much simpler.
    Total volume = 6197.5056 cubic feet = 175.494 cubic meter
    Submerged volume 4/5 (0.8) of total volume = 4958.004 cubic feet = 140.39 cubic meter
    64lb/cubic feet of seawater displaced x 4958.004 cuft of submerged volume = 317312.28 lb = 143.93t
    So if you want to submerge that conic/cylinder shape to 4/5 the whole object (that is including the crew and their rubber ducks) must weigh 143.93t. How much is ballast, structure or payload is irrelevant, seawater is pushing up with 143.93t so you must push down with an equal force, meaning you must provide the mass.
    As I said this puts us solidly into J-class yacht displacement territory, so needed sail area will be at least the same, around 7500 square feet. Actual sailarea depends on target speed under chosen conditions and could be less or more depending on the SOR (with a desired average speed in fair weather of 20kn I expect much more).
    Given the hull configuration the only way of doing it would be using A-frame masts. The sail by wire aspect is solved, all superyachts do it.
    The canting ballast/rig and the true submarine requirements I can not comment on. I can only say that even if you solve the technical parts of stress and weight distribution the handling of the whole object will be nothing like you imagine. If you really want the thing to be able to submerge even the nice interior you seek will disapear, it will get as crowded in there as any WW2 sub.
     

  15. NautiPhillip
    Joined: Aug 2019
    Posts: 27
    Likes: 1, Points: 3
    Location: Seabrook, Texas USA

    NautiPhillip Junior Member

    Great GIF! Thanks!

    However, as I mentioned earlier in the thread, the intent is to; 1) Modify the bow to pierce waves and; 2) to run awash. In this case the only wake produced is a minimal ripple produced by the tower (in this case, the bridgedeck).

    What we are examining at this stage is basic hull shape designed to incorporate the speed advantages of a VSV L/W ratio somewhere around 9-10:1.

    Thanks for sharing that though. Your points are well taken and must be accounted for in cases where the vessel must run light of it's intended displacement.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.