Mini - Motorboat “New Flamingo“

Mini - Motorboat “New Flamingo“​

1. Introduction
The present design is designed as modification of the mother created of Japanese company "Quyova" - “KT-8S Flamingo”, described in the journal „Motorboats and yachts” №31 - 1971, in the publication „Is extendable acquaintance to trimarans” from D.Antonov. He is evocative and in the book „Motorboats, boats and motors in problems and answers”,1977 from G.M.Novak.
Characteristics of Flamingo:
LH x BH x H = 2,6m x 1,25m x 0,6m
Material of the hull is plastic, without frame construction
Number of passengers - 2
Velocity with outboard motor:
At power 8 hp -in planing condition with 30 km/hour, at 18 hp-40 km/hour
The Linesplan without the table of offsets and general view photo is published.
2. Making computer model
From the Linesplan through the program “Grafula 2” coordinates X, Y and Z the reference points, superjacent on the shown frames, as well on the outlines of external contours -deck, coamings and transom are fixed.
Everything else as design is made by the program Rhinoceros 5, and all accounts - on Orca3D.
3. Differences from the mother
For want of the table of offsets and if there is a tunnel geometric shape in the fore, would be absurd to receive absolutely complete coincidence of the hulls. It is notably in the fore of the computer model, where water-lines more smoothly varying.
The design of the stern recess and the wind protective glasses is changed. It is added liferail. The construction of the seat - it general is changed as against two separate armchairs of the mother. More powerful motor - 25 hp, instead of 18 hp is chosen.
4. Characteristics of model and feature of the hull
4.1. Characteristics of the modified model:
Class on classification of the European Community - „C and D”
LH x BH x H = 2,6m x 1,25m x 0,638m
LOA x BOA x Hmax = 2,634m x 1,286m x 0,691m
H - distance of the tallest point of the coamings /the bulwarks/ from BL
Hmax - distance of the tallest point of the deck from BL
The Linesplan at program Orca3D see on Fig 1. The table of offsets see on Fig1a.
The Linesplan on program Delftship Professional can be seen on Fig 2.
Hydrostatic curves over the range water-lines 0 - 0,38m from BL on program Orca3D see on Fig 3, 4 and 5.
Weight and Cost Report is possible to see on Fig 6.
From Planing Analysis Report the resistance curves of water and the power in dependence on velocity in knots - Fig 7 and 8 are shown. The service speed at planing is 30 kt.
On Fig 9 the running trim angle in dependence on velocity is shown.
The Perspective views of the Motorboat can be seen on Fig 10 - 14.
4.2 Features of the hull
The hull is produced from plastic from four parts - the basic hull, liferail, deck with coamings and stern recess.
- The basic hull has a two-tunnel form consisting of a basic average body and two side sponsons. The Sponsons are obviously expressed in the bow third of the hull with keel lines above the keel in CL, and then gradually transfer in horizontal areas of the bottom at the aft transom.
The Bottom has a deadrise with two longitudinal planing steps and rounded bilges. At once above it, between the bottom and sides spray reil is made. This form warrants sufficient rigidity of the without frame hull.
The bottom is made from fiber-glass-reinforced plastic a type "sandwich".
- The Liferail has box rectangular /10 х 70/ construction on the periphery of the boat on sides and transoms with exclusion the place of bracing of the outboard motor. On external edges of the Liferail is mounted rubber collar with thickness of 1/4”.
- The deck is from the same material as sides - Choped-Strand mats. In CL the equal area for transition from the bow in the cockpit is made and special flanges above laps of passengers are stipulated.
On the deck, on right and left-handed to the side wind protective glasses are installed. To the lower face of the deck sheets of plastic foam for unsinkability are fixed.
The coamings box /trapezoidal/ constructions are from planes of fiber-glass-reinforced plastic a type "sandwich", as well as the Liferail. The internal volume is filled by plastic foam for unsinkability.
The Stern recess present itself drain niche from fiber-glass-reinforced plastic. Lateral watertight volumes fulfill the role of air-compartment for unsinkability.
5. Operational Load cases of the Motorboat- see in the tables on Fig 15.
6. Accounts of intact stability in the basic case of load /total displacement at two passengers/ by the basic criterion - wind heeling moment and by additional criterion - turning stability, under Rules River/2008/ and Marine/2010/ Registers of Russia.
The static and dynamic stability diagram with construction for deriving the arms of the Righting Moments is shown on Fig 16. The angle of flooding θD = 35deg. The admissible turning angle θR = 15 deg. The Silhouette at mean draft Tm=0,2075m see on Fig 16а.
Outcomes only for the basic case of the load №1 are shown on Fig 17 for height of waves up to h1%=0,6m, corresponding to working area "3" on classification for internal waterways of Europe.
It is visible that by the basic criterion we have a high reserve of intact stability /К = 8,51/, and by additional criterion /turning stability/ should be reduce the speed of the course previously up to 9,5 kt and thus an acceptable stability factor 1,069 is received.
7. Tests it agrees ISO 12217-3 for Motorboats with L<6m
The supplemented tables on Checklist see on Fig 18.
8. For performance of all tests, required on ISO 12217-3, it is necessary to load the Motorboat with different weights which at definite cases can be changed from people.
Cases of load before tests are shown in tables on Fig 19 /test cases of load № 1-8/.
At some tests - № 3-8, the boat previously is necessary to fill in preparatory cases of load with fresh water - 0,3m3 / 300 kg/, as shown in cases of load for test.
The Tests on the damaged stability and swamped buoyancy will show concrete outcomes after ultimate availability of the boat. For this reason the Checklist is not supplemented ultimately. He can be ended only at a real, instead of virtual test.
9. Outputs and advisories for New Flamingo:
9.1 Outputs
- For all cases of load the initial transversal metacentric height is positive and more 0,2m.
- The real distance from the water-line with trim and heel in the initial state up to the critical point of downflooding always is more 100mm which meets the requirement for a class "C" on the European classification about categorization of the construction of small ships, but with limitation on height of waves up to h1%= 0,6m.
.
From it automatically follows also the output that the boat is supposed to floating and in area corresponding to class "D".
The analysis for the velocity and power at D=354,45kg shows that the most optimum is velocity 23kt, at which water resistance is the smallest and the running trim angle acceptable - 4,228deg.
At increase of velocity the running trim angle is reduce.
At a planing speed 30 kt power of the outboard motor 23,6 hp is necessary, at a running trim angle sternward - 2,762 deg.
At v=30kt water resistance Rtotal=569N, and the volumetric Froude number
Fnv = 5,857> 3, that is the boat is planing. Thus:
The effective width of the planing plate is equal 0,97m, and the effective deadrise of the plate is equal in midship 8,152 deg.
9.2 Advisories
- Before enter in circulation the velocity of the boat is necessary to reduce up to 9,5 kt and the passengers is necessary to sit down on the places.
- To not suppose a case of load when the skipper sits on the place at the right side and the passenger is stand up behind of him in the boat in all growth, in proximity up to the right bulwark. Then the water will swamped the cockpit through the most low critical point /the cross wall of the stern recess/-the point of downflooding.
- The skipper is necessary to be with big experience because of longitudinal stability /Porpoising/.
10. What is necessary, that the present publication has turned to the completed engineering design?
First of all it is necessary to appear client wishing to implement this design and which will form his vision and expectations for the ultimate product in "Technical assignment".

I accept problems and easygoing critical notes on the following e- mail:
<razmik.baharyan@abv.bg>
Dipl. Eng. Razmik Baharyan

 

I like this boat. The only suggestion I could offer is to wait to make the deck mold until after you have done water trials with the hull under way to determine if you wanted to have the seating farther aft. Of course you may have already been planning on doing that. So I wish you the best with this project.

 

Looks fun.

 

2.6 metres long ? The stability calculations are probably more academic than anything else, a couple of victims of the "obesity epidemic" could throw all that out the window ! I imagine the advent of jet-ski type watercraft has pretty well edged this type of thing out.

 

Hi Gilbert,
The seat is impossible advance aft ward or to the bow. Centre-drilling of the motorboat will be broken. The running trim will be unacceptable. Thanks for kind reply.

 

Hi, Mr.
I am a professional and my answer will be such:
Both major vessels and motorboats at designing and construction are subject to rules of the classification societies, accepted in the corresponding state. But except for that they due it will be tested on Stability and unsinkability on ISO12217. The maritime administration does not suppose floating without this document Checklist. So that will be very incompetent if to say that all these accounts can be dropped from the window.
For jets with a water-jet propeller I can say the following: The truth what is it rather new designing, but it completely that they in will not signify to exchange small motorboats. If the backpacking is too long then in the boat can be put baggage, food, water and backup of fuel. Probably and tent it is taken. And how it will be with jet - will put all in a bag and take on the back? Any floating structure has the applicability. For this purpose I and write - before to begin the design, designer is necessary to receive the Preliminary Technical task. If the client has written that wants the design of a jet, to signify it is necessary to make a jet and if wants a boat then it is necessary to think of a boat.

 

Thanks for the reply , maybe we have a small language barrier here, though your English is much better than my Bulgar(ian). It just seems to me that this little boat would have more market appeal if waterjet powered, we live in a more safety conscious world today, and zipping around in the inshore areas with an outboard increases the chances of a snorkeller getting sliced and diced.

 

As far as I have understood you be afraid from damage of the outboard motor by operating in area with shallow water. The client determined the navigation area in the Preliminary technical task /specifications/ for the designer. Certainly if the route is chosen with shallow water then the water-jet propeller is better accepted. I thought of this alternative before to begin model. He is possible but at longer boat. At alternative 2,6m it is impossible from - for centre-drilling. The increase of the weight in the stern means an increase the planing trim. Now there are also electrical outboard motors with a water-jet propeller. But the most ideal alternative at floating on littered with shoal and sand spits to small rivers, and also swamps, the overgrown cane and seaweed is the outboard motor with air screws. But at such area I would pick a vessel on Air Cushion Craft than planing without delay. But all depends on the client what he wants to receive on finish.

 

That cathedral hull is going to be noisy and bumpy in a chop

 

Hi All,
It is possible, but if the boat leaves in condition "porpoising". I think that all depends on that under what angle to waves is going the boat and with what velocity. For that also I was written that the motor-man is necessary to be experience and if necessary will sink velocity. But if the speed restriction it is required will be visible even at the testing.

 

See attachment file-Fig 19

 

None of the load cases correspond to cases the ISO requests that are to be studied. See attached a figure with weights that ISO requires.
The establishment of these weights is the first step to carry out a series of calculations. What are the calculations, from there, you think to accomplish?. By the way, what category of design have you adopted for the boat?. Without knowing that, you can not know what the ship has to meet.
A very creditable job but has only just started, from now on is the hardest thing to do. Do not miss half finished, go ahead and be successful. Hope to see your results.

 

Dear Tansl,
You have disappointed me. I expected to conduct an interesting engineering controversy. And what is received? You again hurry to give your opinion before closely to consider all that published in this thread. You did not pay attention that in the publication there is a file under a name “Checklist by ISO 12217-3-Stability of New Flamingo, D=354,451kg, Fig 18” which responds on all your questions.
Nothing can be calculated for stability of this motorboat because there is no ready boat which more to subject testing and I was written that these load cases for testing are made only as a preliminary preparation to facilitate the further work at tests.
Yours faithfully, Rabah

 

I'm sorry you dislike so everything I say, I just pretend to help you because I see that you need a lot of help.
I do not understand what you say because, surely, your English is not good, mine is bad and also you do not know well what you're talking about.
My experience, excuse me to tell you, is that the loading conditions of a boat can be studied even if the ship does not exist physically. But perhaps they have changed the methods in naval architecture and now can not study anything, or can not predict the behavior of a ship, until it is finished.
A friendly advice: if you want to project boats, in Europe you would do well to study ISO standards applicable to them. Make a pretty pattern of a boat is only a small part of what needs to be done. And this is certainly true, your model, how beautiful it is, if does not meet the standards that must be met, is not a boat.
As always, Rabah, was a pleasure. I hope our conversation was in the field of high engineering in which you like to move.
Cheers

 

Hi Tansl,
You are right that it is not yet the completed engineering design of the boat, but I have suggested for this purpose in point 10 of my publications.
About the standards of ISO on which it is necessary to respond the boat except for ISO 12217-3 for stability, you likely mean ISO 12215-5 and 6 for scantling of structural members of the motor boat.
It will be the following development cycle - to prove that the accepted thickness of the shell plating and the deck is strong enough and steady. But it can be made only if there is a client, differently it is not meaning.