AnthonyH
Member
Good morning Mudisox,
Weird, how so?, Please explain.
Cheers,
Tony
PS: Pardon my ignorance, what does IMHO mean?
Catalac 9M confusion
- Thread starter MSJourney
- Start date
Good morning Mudisox,
Weird, how so?, Please explain.
Cheers,
Tony
PS: Pardon my ignorance, what does IMHO mean?
AnthonyH
Member
Hi, Rappey,
That's great, it must have been a lovely sight, surfing speeds? (Keep your camera close if you are in that part of the world again). What's good here is that it shows that there is life in our old hulls yet! they just need enough driving force?
Cheers,
Tony
AntarcticPilot
Well-Known Member
In My Humble Opinion
AnthonyH
Member
AntarcticPilot
Well-Known Member
Many moons ago (mid 60s), my Dad booked us a test sail on a Catalac - probably an 8m. We all enjoyed the sail, and perhaps if the price had been a bit lower, we might have ended up with one. But I do recall that the performance was perfectly adequate, and certainly gave an impression of great speed by comparison with monohulls of the day. And, of course, the accommodation bore no comparison to a monohull! I do recall the sales person being very eloquent about the hydrodynamic design of the hulls, which was intended to reduce slamming under the bridge-desk; at the time this was a notorious problem with catamarans. He also spoke about the issue of capsizing - again, at the time this was a big concern for catamarans, with all sorts of solutions, from Donald Crowhurst's inflatable bag system to flying-saucer like floats at the top of the mast. Again, the hull design explicitly addressed this issue. My main visual memory is of the motor-boat like wakes of the hulls meeting just behind the bridge-deck.
If I were considering another boat, a Catalac is one I'd give serious consideration to.
If I were considering another boat, a Catalac is one I'd give serious consideration to.
AnthonyH
Member
Hi J. When? Of course, this is the big question? I have set myself to work on a huge project. I have the windows and the new exterior mouldings made and fitted and also two lovely looking refurbed 14 HP engines sitting in the garage, and I also have the interior stripped out, and that’s about it so far!
So if I was dreaming say 2 years!!
I will say that if I hadn’t had the boat parked next to the house, I don’t think I would be anywhere as near as I am now.
Your E thruster unit sounds an interesting project although I can’t quite envisage its design? with its pivoting multi directional thrust ?? and/or how and how long you would need power it?
Well good luck with it.
Cheers,
Tony
PS: Share more if you wish, I won’t patent it!
jnjanversteeg
New Member
Hi Tony. It is a 2 kW motor 24 V from Caroute-outdoor. It came in last week from China. It will swing from an extended platform that I create by adding a 2.75 m long carbon tube over the outerpoints over the bows. When not in use it will hinge back under the bottom of the boat, pulled back by a line from the aft of he boat. When to be put in use, the line will be released and the motor swings forward. It is side ways supported by two diagonal M10 threaded rods in a spanner. In forward direction, it is kept in postion by its thrust. For backward fixation I wil make some king of brace that is also retractable. The motor can pivot around the vertical axis over about 135 degrees. Startposition is 90 degrees wrt the boat 's longitual axis. It is then of the smallest dimensions when swung under the bottom. In this downward position it functions as a bowthruster with forward/backward thrust as well as power as variables. (Max thrust about 70 kgs according to specs.) Then, from this positon the motor can pivot 135 degrees. So maximum or key positions: 45 degrees to port, straight forward, 45 degrees to starboard,90 degrees to starboard,(which is the folding position also). I will use a outboard steering device for pivotting it. Controlling this can be via an extra wheel but that is crampy as well as weird in the cockpit so I am considering a 24 V dc motor, remote controlled via a H bridge. Coupled to the steeringhouse of the unit. I added a little sketch, will work on something more decent though. For the battery, I ordered24 LiFePO4 60 Ah pouches from GWL in Czech Republic and a "Overkill BMS" from USA. As said motor came from China. (Mind all those tariffs.....) So the batterypack will be 4.6 kWh and with a degree of discharge of about 60 % that will make 2,8 kWh. I expect usage of about 25 - 50 % so 2.8 hrs or longer?? I might also add a carbon fiber rack with two 250 W solar panels later when it works out. It is rather costly, expect it to be around 3500 - 4000 € so hope it works but OK, it makes fun in these times of Covid. Some motivations: I changed from flat rudders to profiled and experienced that spinning around and motoring backwards became more difficult. Profiled rudders work perfect when going forward but backwards is more of an issue. The marine box I am hiring is crampy and often wit a lot of wind. Getting in and out is an annoying thing. My wife hates it so this provided a good reason for the invest
Then I have 2 times 10 hp Vetus diesels. And that appears to be very marginal. So these additional 5 hp might work when needed. My wife prefers the channels for boating so it would be nice to enjoy in silence. Additional battery power for boiler, cooling etc when no 220 V available. And then that windward performance hey....It was, is and remains a challenge over the years so will give me a nice focus in the coming years of retirement. (Agree, better buy something else but that is the easy way, and we should be circular those days shouldn't we..) By the way, the extra platform over the bows allows for an anchor winch, might store a foldable dingy and that nasty clamp can be removed from the fore deck also.Counter reasons, a lot of weight there will create additional hobbyhorsing. The motor will add 25 - 30 kgs or so in total. I was intending to do a lot in carbon but setting it up now in SS for ease of construction. Also, how robust will it be in really choppy conditions? Do I need an extra fixation mechanism when folded and the 'shit hits the fan'? Fulnerable to theft as the motor is easy accesible...
I hope to do first tests later this month or in november. Might better have done it in the summer as it would have been a nice activity from outside the boat, dipped in the IJsselmeerwater of over 20 degrees C. Anyway, will report more details on Catalac Catamarans facebook site when appropriate.
PS: no problem when you patent it as long as you call the concept 'swinging Dutchman'
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AnthonyH
Member
Hi J,
Wow! As Monty Python show used to say “now for something completely different”.
About ten lines into your narrative I began to feel a little faint
, as I suddenly thought I had been transported back in time to my old work (marine/mechanical, C. Eng).
So, just to summarise so far: You say: -
-Your 2 Kw motor “came in last week from China”.
-You say “I am considering a 24 V dc moto”.
-The system drawing is on-the-back-of-a-fag-packet level.
-You say, “I hope to do first tests later this month or in November”
Pardon me if I sound a little sceptical about this project, but suffice to say you would hardly be likely to be able to start tests or trials in the next six weeks? Indeed I would be surprised if you had fully unpacked the 2 Kw motor yet??
As you have put considerable effort and thought into this descriptive narrative, I might suggest that if you are looking for exceptional port manoeuvrability, as you have 2 X 10Hp engines just fit a standard bow thruster into one of the hulls and you will have it all.
The general principle (where possible) when designing offshore/marine systems is- KISS, Keep is simple, stupid.
Cheers,
Tony
Wow! As Monty Python show used to say “now for something completely different”.
About ten lines into your narrative I began to feel a little faint
, as I suddenly thought I had been transported back in time to my old work (marine/mechanical, C. Eng).So, just to summarise so far: You say: -
-Your 2 Kw motor “came in last week from China”.
-You say “I am considering a 24 V dc moto”.
-The system drawing is on-the-back-of-a-fag-packet level.
-You say, “I hope to do first tests later this month or in November”
Pardon me if I sound a little sceptical about this project, but suffice to say you would hardly be likely to be able to start tests or trials in the next six weeks? Indeed I would be surprised if you had fully unpacked the 2 Kw motor yet??
As you have put considerable effort and thought into this descriptive narrative, I might suggest that if you are looking for exceptional port manoeuvrability, as you have 2 X 10Hp engines just fit a standard bow thruster into one of the hulls and you will have it all
.The general principle (where possible) when designing offshore/marine systems is- KISS, Keep is simple, stupid.
Cheers,
Tony
jnjanversteeg
New Member
Hi Tony
Agree with KISS, but lets go out of the box from time to time... (Whole career was in the light of KISS already, (also mechanical (andprocess/process control)-engineer. I am KISSed to dead in the mean time.) Sorry wrt the fainting, hope did not spoil the weekend.
Sketch, what is in the name.... produced it while sending the post. Hope it shows elementary concept of the axis of rotation. I made detailed drawings but adapted in the mean time, have no up to date set now but will provide photo's once ready. Not sure what you mean with unpacked the motor....
An issue to decide this week is where to let the vertical tube of the motor swing/hinge so if will fit nicely under the boat as the bottom is curved. The hinge should be sufficiently low to catch the profile so to say to keep the retracted motor high enough above water-level. Have to use the dingy to be on the spot.
Bow thruster, clear, I know, but a big hole in the hull and again not contributing to windward performance as this hole adds to drag( although minimal with a profiled shape around it as I read somewhere. ) The E-motor will help sailing to windward in silence and is retractable anytime. And is for me an experiment with E-propulsion.
On top of that, I guess you are familiar with the quote : “Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats.” I think especially Catalacs are created with that in mind as you look at the variety in designs and creations on the internet.
Anyway, I am very interested in your experiences with the LAR keels. Can you share some calculations about windforces, sail area/reefing etc? How did you decide on dimensions of the keels? I know of Lars Ouddrup who provided simple rules of design from the time that computer design was not common. He took as an example a 9M in a publication for the Dutch Catamaran and Trimaran club and designed daggerboards. The maximum surface ( from the view of boat stability) is some 1.3 m2 per side and they could create forces on the hull up to ( I recall) several tonnes under unfavorable conditions. I have this article somewhere so can share more details if you are interested.
I will also ask further about the swing keel that was applied under an 8 m as shared recently on the Catalac facebook site.
Then I saw somewhere on a forum, a photo of a dried out 9 m with also a bow motor but not at a detailed level. Cannot find it anymore, should have saved at the time....So if somebody could help...
With respect to time schedule, I'll get me on the way home (I am an uncomfortably 260 km's away from the boat...) the 'bows tube', And decide on the way to pivot the motor with this outboard steering mechanism. These are available in many types and dimensions. The additional 24 V motor I said I was considering was about how to enforce/realize pivoting. KISS is with a little handwheel as this pivotting is only a rare thing during sailing with the motor in use. Not so KISS is the long cable from the bow to the central steeringnposition and a neat physical location of this handwheel. So a solution can be a electrical motor powering the steering-mechanism, located in a forward locker.
Plan to proceed with welding in the next week then waiting a nice wheather window.....
Agree with KISS, but lets go out of the box from time to time... (Whole career was in the light of KISS already, (also mechanical (andprocess/process control)-engineer. I am KISSed to dead in the mean time.) Sorry wrt the fainting, hope did not spoil the weekend.
Sketch, what is in the name.... produced it while sending the post. Hope it shows elementary concept of the axis of rotation. I made detailed drawings but adapted in the mean time, have no up to date set now but will provide photo's once ready. Not sure what you mean with unpacked the motor....
An issue to decide this week is where to let the vertical tube of the motor swing/hinge so if will fit nicely under the boat as the bottom is curved. The hinge should be sufficiently low to catch the profile so to say to keep the retracted motor high enough above water-level. Have to use the dingy to be on the spot.
Bow thruster, clear, I know, but a big hole in the hull and again not contributing to windward performance as this hole adds to drag( although minimal with a profiled shape around it as I read somewhere. ) The E-motor will help sailing to windward in silence and is retractable anytime. And is for me an experiment with E-propulsion.
On top of that, I guess you are familiar with the quote : “Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats.” I think especially Catalacs are created with that in mind as you look at the variety in designs and creations on the internet.
Anyway, I am very interested in your experiences with the LAR keels. Can you share some calculations about windforces, sail area/reefing etc? How did you decide on dimensions of the keels? I know of Lars Ouddrup who provided simple rules of design from the time that computer design was not common. He took as an example a 9M in a publication for the Dutch Catamaran and Trimaran club and designed daggerboards. The maximum surface ( from the view of boat stability) is some 1.3 m2 per side and they could create forces on the hull up to ( I recall) several tonnes under unfavorable conditions. I have this article somewhere so can share more details if you are interested.
I will also ask further about the swing keel that was applied under an 8 m as shared recently on the Catalac facebook site.
Then I saw somewhere on a forum, a photo of a dried out 9 m with also a bow motor but not at a detailed level. Cannot find it anymore, should have saved at the time....So if somebody could help...
With respect to time schedule, I'll get me on the way home (I am an uncomfortably 260 km's away from the boat...) the 'bows tube', And decide on the way to pivot the motor with this outboard steering mechanism. These are available in many types and dimensions. The additional 24 V motor I said I was considering was about how to enforce/realize pivoting. KISS is with a little handwheel as this pivotting is only a rare thing during sailing with the motor in use. Not so KISS is the long cable from the bow to the central steeringnposition and a neat physical location of this handwheel. So a solution can be a electrical motor powering the steering-mechanism, located in a forward locker.
Plan to proceed with welding in the next week then waiting a nice wheather window.....
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Boathook
Well-Known Member
jnjanversteeg
I'm interested in those Lar calculations and the article if you can find it.
cherod
N/A
I have long considered a forward central propulsion unit and the development of E motors which can be run free and silently from solar panels makes the concept all the better ( logistics permitting )
jnjanversteeg
New Member
ok, will look for it when at home and translate it as it was in Dutch. Jan
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