What equipment for an aluminium boat building shop?

Discussion in 'Metal Boat Building' started by RSD, May 9, 2024.

  1. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    Cheers - that would be great!
     
  2. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    A question for those in the know - would a laser cutting table produce any swarf, chips, dust etc? I was just thinking that perhaps if that was the case then there wouldn't be a risk of contamination of aluminium welds from cutting other materials on a laser table after all? Certainly there would be with a router table though.
     
  3. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    One other question for the experienced guys - Laser welding is good for up to 6mm or 1/4 inch aluminium. At roughly what length catamarans are you likely to start seeing the drawings calling for thicker aluminium than that?
     
  4. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    You should be able to build a 20 metre power cat w1ith 6 mm thick aluminium shell plating , although the scantlings will be affected by the desired service speed (will the 20 metre cat have to be capable of 25 or 30 knots?), and the frame spacing (of both the transverse frames / bulkheads and the longitudinal stiffeners) will also have an effect.

    The relevant Rules will provide guidance on this. For instance they might specify a frame thickness greater than 6 mm.

    If your catamaran is regularly doing beach landings, with the bows coming into contact with the sand, then you might want to use thicker plate for the keels in way of where the contact with the beach is.

    If you want to build cats up to 24 metres loadline length then you will most probably need to use thicker (than 6 mm) plate in some areas of the hulls.
     
  5. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    Will be looking for around 30 knots - using waterjet propulsion.

    I haven't been able to find out what the "relevant rules" are for building in Egypt - it is quite possible that there aren't any - but it is damn difficult to know! If anyone knows please let me know!

    Beach landings aren't normally performed there - not planned ones anyway. Hitting shallow coral reefs is a real hazard though...

    Given the speed and simplicity advantages of laser welding I think that it is best if we keep the boat length of whatever we are doing to those that can be built using up to 6mm aluminium - keep everything as simple as possible.
     
  6. bajansailor
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    Location: Barbados

    bajansailor Marine Surveyor

    That is pretty fast relatively - and if you have choppy conditions in the Red Sea, and still want to maintain 30 knots, then that will call for careful hull structure design.

    Sorry for the misunderstanding - the Rules are not from the Flag State (ie Egypt) as such, but from a classification society.
    DNV-GL have rules for high speed aluminium craft - I am not allowed to attach a copy of the Rules here, due to copyright rules, but here is a link where one can sign up to get the Rules.
    Rules and Standards Explorer https://store.veracity.com/rules-and-standards-explorer

    The other class societies like Bureau Veritas, Lloyds Register et al all have their own rules as well - for example Lloyds Register have Special Service Craft Rules.
    Classification of Special Service Craft | LR https://www.lr.org/en/knowledge/lloyds-register-rules/rules-and-regulations-for-the-classification-of-special-service-craft/

    It sounds like it would be useful to have some relatively substantial keel plates on your hulls for those (inevitable?) occasions when they have encounters with reefs - and they would quite likely be thicker than 6 mm.

    There are other folk on here like @Ad Hoc and @TANSL who can offer you much better and more comprehensive advice than I when it comes to the subject of designing fast ally cats according to the Class Rules.

    Edit - the easiest way to obtain a suitable design for a Red Sea dive boat would probably be to look at existing aluminium passenger catamaran designs - Teknicraft are one of many naval architects who have proven designs on their webpage.
    Teknicraft Design https://teknicraft.com/work/passenger-vessels/1/34
     
    Last edited: May 14, 2024
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  7. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    Some days certainly won't be able to maintain 30 knots, other days the water is flatter than a pancake. Looking at the wave measurements/predictor in Windy for the next few days for Panorama Reef - it is 1.6 metres, 4 second interval for the next few days, dropping to 0.6 m/3 second interval in about a week. At most dives regions there are more inshore reefs that can be used when the weather is really terrible - but they get very crowded as all the boats are there.


    Ah sorry - my bad. Judging by what I have seen on these boats I highly doubt that any Egyptian dive boat is built to the requirements of a classification society - in fact a classification society would probably freak if they stepped onto an Egyptian dive boat!

    Many thanks for those links - they will certainly help give some guidance!

    I was thinking perhaps of some "sacrificial" additional layers of 6mm that were welded on - use them kind of like a marine version of the skid plates that throw all the sparks on the rear of a Formula 1 car.

    Cheers - will pick their brains!

    I'm thinking the same thing - really it is just the interior fitout that would be different, and fitting things like a diver lift to the stern etc.
     
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  8. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Undoubtedly so!
    But the main purpose of the Rules is to provide guidance for anybody wanting to do the structural design themselves - if the boat is designed and built according to the Rules, then it should be able to cope with the conditions it is designed for.
    Whereas the 'average' Egyptian dive boat might not, if it was designed on the back of a proverbial fag packet.

    But your easiest option is probably to research all of the 'small' (under 24 metres) fast aluminium ferry builders, and see what they have re stock plans available.
     
  9. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    I think that they have drawings - but not drawings designed using rules. The ones to be really careful of over there are the ones that have had the superstructures modified after the first couple of years - they tend to add more to the superstructure and then become very top heavy! All of them do tend to be quite top heavy which doesn't help the roll situation.

    Totally agree - will start with Teknicraft and then search for others as well.
     
  10. C. Dog
    Joined: May 2022
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    Location: Coffs Harbour NSW Australia

    C. Dog Senior Member

    @RSD I have worked at both tiny and huge fabricated aluminium boat manufacturing plants in Australia.

    The really big ones have their own trimming and upholstery departments and do contact work for other manufacturers, including seating for ferries and aircraft. It is handy when your main industry is in a lull to have other strings to your bow.

    The worst things I saw were poor planning causing welders to go back in after painters, electricians etc, causing lots of expensive rework, it was not uncommon either.

    Another pitfall comes from chasing deadlines by having multiple crews aboard at once, all getting in each other's way, and each thinking what they do is the important job. Some will deliberately sabotage another crew's work due to feuding, childish stuff.

    BTW I have seen good fabricators cut out a 60' monohull dive boat on a concrete floor with a handheld Makita 9¼" circular saw and weld it up alongside where they built it. Took about two weeks and the boat is still in service about 25 years later as far as I know.
     
  11. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    Fancy a trip to Egypt?:)

    Totally agree! One of the keys will be to bring in additional work for the laser cutter. At the same time I don't want the operation to become too big either - I don't want this -
    upload_2024-5-14_14-59-43.png

    Don't they use Hold Points to check that everything is ready before they send in the next trade?

    I can see everyone getting in each others way happening in Egypt - but that is because they are keen to work rather than deadlines. Usually there isn't any childish stuff there though.

    No doubt that can be done if everyone is experienced and knows that they are doing!
     
  12. C. Dog
    Joined: May 2022
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    Location: Coffs Harbour NSW Australia

    C. Dog Senior Member

    All prior planning and safeguards become irrelevant when the client or, less often NA, change their mind or forget something. Strive for perfection, but from hard experience it is unattainable.

    I would love to spend some time in Egypt, however I do not believe I am who you want. I was entering various factories to install systems (mechanical, hydraulics and some electrics/electronics) as a contractor. You need a production manager with personal alloy boatbuilding experience in my opinion.

    I wish you every success.
     
  13. RSD
    Joined: Nov 2022
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    Location: Red Sea, Egypt

    RSD Senior Member

    I've found a Teknicraft design that would suit with very little modification. Teknicraft Design https://www.teknicraft.com/Capt-Murchison It is designed/built to USCG Subpart T - obviously I'm not familiar with that set of rules so could someone kindly give some commentary on how it compares to say DNV, Lloyd's etc. The Captain Murchison is used for operations 200 nm out into the Gulf of Mexico so it should be able to handle most things the Red Sea throws up.
     
  14. RSD
    Joined: Nov 2022
    Posts: 150
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    Location: Red Sea, Egypt

    RSD Senior Member

    Does anyone have any experience with CNC Waterjet cutting for aluminium plate for boat building? Local non-boat fabshop suggested that I take a look at it instead of laser due to the lack of heat input etc?
     

  15. PeterMck
    Joined: Dec 2023
    Posts: 1
    Likes: 1, Points: 3
    Location: Indonesia

    PeterMck New Member

    Just came across your thread and am very interested in following along.
    Using grit-entrained water would likely contaminate the material being cut.
    During my apprenticeship, in a factory producing fiberboard, the end were trimmed with 15k psi water jet using a garnet nozzle and I doubt it would cut 6mm 5083 aluminium.

    I was fortunate to find a lot of equipment that was being sold after a 10m aluminium dive boat was completed in Bali.
    The main item was a CNC gantry plasma with a 4m x 10m cutting table, dual pulse mig with removable wire feeder and long stinger.
    Indonesia power is unreliable at times so the equipment included a 55 kva 3PH genset used to power the table, MIG and compressor.
    Currently looking at a location in East Java to set up my workshop and will focus on building workboats under 20m.
     
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