Analysis of real underkeel clearance for Świnoujście Szczecin waterway in years

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1 Scetfc Jourals Martme Uversty of Szczec Zeszyty Naukowe Akadema Morska w Szczece 2012, 32(104) z. 2 pp , 32(104) z. 2 s Aalyss of real uderkeel clearace for Śwoujśce Szczec waterway years Marta Schoeech 1, Sylwa Sokołowska 2 1 Martme Uversty of Szczec Szczec, ul. Wały Chrobrego 1 2, e-mal: martas@am.szczec.pl 2 Martme Offce Szczec Szczec, pl. Batorego 4, e-mal: sylva.sokolowska@gmal.com Key words: real data, probablstc model, uderkeel clearace Abstract The paper presets the practcal usg of model for uderkeel clearace evaluato. Real data from Martme Offce cocerg shps whch eter ports was used to aalyss of results frst probablstc model of uderkeel clearace ad ext tegrated system. Durg aalyss mea probablty that uderkeel clearace wll be less tha zero was determed for ports Śwoujśce, Szczec ad Polce. Results of ths aalyss ca be used for further research coected wth tegrated system for uderkeel clearace calculato. Itroducto Uderkeel clearace of shps (UKC) s the clearace betwee shp s hull ad the bottom of water area, so t s the most mportat factor whch determes the possblty of shps groudg. Matag safe clearace s the basc avgator s resposblty amog hs other usual dutes. Tradtoally, most ports Polad ad Europe have operated uder fxed rules whch gover the mmum uderkeel clearace to permt safe trast durg etrace to restrcted areas. The determato of mmal UKC s especally mportat for these port whch basg the exstg meteorologcal codtos ad the type of vessels, to load the vessel maxmally [1]. Due to developmets shppg, ports are uder cotuous pressure to accommodate wder ad deeper-draught shps. Good soluto s dredgg of the etrace to the port, but t s a expesve opto. Therefore, very mportat task s to fd maxmum safe draught of a partcular type of shp for a exstg port etrace chael [2]. If UKC requremets are too coservatve, shps carry less cargo tha they could, ad the operato s ot as ecoomc as t mght be. At preset Polad all UKC calculatos are doe usg method of costat clearaces whereby a mmum uderkeel clearace s declared by the regulatory authorty. Some ports have specal VTS procedures for eterg ad leavg, ad Mare Authortes have problem wth decso accordg to etrace bg- -draught vessels. The maxmum draught s lmted by the avalable water depth mus uderkeel clearace [2]. Mare staff at the ports eeds a adequate decso support system to allow them to take shp allowace decsos based o proper ad relable data [3]. So, Martme Uversty of Szczec frst probablstc model for uderkeel clearace determato was created to determe safety for gve shp ad ext Mare Traffc Egeerg team rebult ths tool ad creates a tegrated system for dyamc uderkeel clearace. Both, model ad system could be used to desg port as a tool for calculatg UKC ad the safety depth for characterstc vessels whch may be exploted gve water area. Because safety level port s very dffcult to determe so practce groudg rsk s calculatg. The paper presets results of verfcato of probablstc model safety evaluato at ma ports Śwoujśce Szczec waterway. 162 Scetfc Jourals 32(104) z. 2

2 Aalyss of real uderkeel clearace for Śwoujśce Szczec waterway years Probablstc model for UKC determato The ma assumpto of probablstc method for UKC determato s that the model takes to accout depth measuremet ucertaty, ucertaty of draught determato port, error of squat determato, bottom rregularty, tdes ad waves fluece [4]. User-etered draught s corrected for draught determato error value, shp s heel error ad wave clearace. Addtoally, terated draught (T ) s calculated as follows: T T r r r S (1) T shp s draught [m]; r draught determato error; T T r p shp s heel error; r f wave clearace; S shp s squaw. Next water level ca be automatcally load from ole automatc gauges, f such exsts (Polsh soluto). I some researches, the level ca be modelled as ormal cut dstrbuto wth parameters (0, ±0.1 m). Depth h was assumed as costat gve sectos: s s m p h h r r pw r (2) s h depth of water area determed o the bass of cumulatve dstrbuto fucto; r soudg error; s r m muddg compoet clearace; pw chage of water level; r avgatoal clearace. Squat (shp skage due to decrease of water pressure durg movemet) s calculated three stages. It s based o sx squat methods ad stadard devatos of factors whch were obtaed usg real expermets. O O u f O u M M (3) u s a ucertaty for the partcular O M method used to obta movg vessel squat (Huuska, Mllward 2, Turer, Hooft, Barrass 1, Barrass 2) Next, dscrete dstrbuto was geerated wth the followg parameters: O 1 u : O u; w 1 : w (4) where w s weght of partcular method. To obta squat dstrbuto, bootstrap method was used, whch ca be used as estmator ad statstc dstrbuto approxmato. Whe assumpto that populato s used due to radom varable O wth ukow dstrbuto F, let O = O 1,..., O wll be a smple sample draw from the set, (O 1,..., O ) tral o realzato, ad R(o, F) statstc estmated at tral seres. Probablty dstrbuto called bootstrap dstrbuto from tral (marked ˆ F) s descrbed by the fallowg formulas: P 1 B k,..., (5) O o for k 1 Statstc R bootstrap dstrbuto s gve the form: R* R o*, Fˆ (6) Basc rule of bootstrap method s that statstc R dstrbuto s approxmated by radom value R*. Whe Mote Carlo method s used, t s mportat that statstc R* hstogram s geerated from the dstrbuto Fˆ, whch s based o N tral realzato. The assumpto s that 1000 [5]. Shp s squat O s determed from ths dstrbuto. Fally uderkeel clearace UKC s determed by usg draught, depth, water level ad squat results whch were calculated before. Uderkeel clearace s defed as: UKC h s r T r s T r r m p h up-to-date depth; s pw r r f S (7) r s soudg error (ormal cut dstrbuto wth 0 ad ±0.1 m); r muddg compoet clearace (ormal m cut dstrbuto wth 0 ad ±0.1 m); T shps draught; r ucertaty for draught determato T f (0, ±0.10 m); O terated squat (bootstrap model); pw chage of water level; r avgatoal clearace (cost. = 0.3 m); r wave clearace (wave heght for partcular weather codtos). Program s capable to cosder above metoed ucertates usg dstrbutos ad ther parameters. Where ucertaty s greater for certa factor compoets due to less avalable data or data accuracy, t s possble to make grater allowaces that factor. The remag ecessary data are take from Zeszyty Naukowe 32(104) z

3 Probablty Marta Schoeech, Sylwa Sokołowska le of equal loss ( ot acceptable, acceptable) Fg. 1. Example of results probablstc model of UKC ad decso support applcato for oe of shps whch etered Śwoujśce Port 2009 XML fle located from the server ad ths fle could be modfy. Decso model results was added to makg applcato user fredly. Smplfed decso model s based o mea expected value. Decso-maker receves suggesto whch cocers to level of acceptable rsk for gve stuato. The model UKC evaluato was mplemeted usg Pytho compler ad t s avalable o-le o Martme Traffc Egeerg Isttute web ste. Form for eterg parameters permts to eter the basc shp ad water rego data. Model uderkeel clearace s evaluated after rug the applcato. The results are preseted as a hstogram ad dagram P(UKC<0) fucto of shp s draught wth level of acceptable rsk groudg fgure 1. Aalyss of results The aalyss covers a perod from 2009 tll 2011 (to August). Probablstc model ad tegrated system were used for all shps equal or loger tha 180 m, whch etered to ports: Śwoujśce, Szczec ad Polce. Parameters of each vessel were etered together wth approprate hydro- -meteorologcal codtos as water level ad wave heght, whch were checked Vessel Traffc System database. Research was carred out o the bass of 168 smulato (Śwoujśce: 96, Szczec: 41, Polce: 31). I smulatos 6 kots speed was used. The results of usg model are preseted table 1. Table 1. Results of usg probablstc model for UKC determato for partcular ports Port Parameter Śwoujśce Szczec Polce Mea P(UKC<0) St.dev P(UKC<0) Mea UKC 95% m m 9 m St.dev UKC 5% m m m Mea UKC 95% m m m St.dev UKC 5% m m 37 m The bggest umber of shps etered Śwoujśce Port, ad from 96 shps whch etered ths port perod Jauary 2009 August shps had o acceptable level probablty of groudg. I Szczec ad Polce the probablstc model has cofrmed decsos of Port Capta. Next, for 11 stuatos Śwoujśce speed was decrease to 3 kots. Values of P(UKC<0) for two dfferet speed are preseted fgure 2. At reduced speed results of decso module system were acceptable wth the excepto of two shps. There are two stuatos, frst for shp Drake wth legth L = 225 m ad draught T = m at water level 509 ad wave heght about 1 m ad the secod for shp Ocea Breeze wth legth L = 225 m ad draught T = 12.8 m at water level 532 ad wave heght about 1.5 m whe result accordg to permsso for safety etrace to the port s egatve. Examples of stuato whe approachg speed smulato was decreased are preseted fgures 3 ad Scetfc Jourals 32(104) z. 2

4 Probablty Probablty P(UKC<0) P(UKC<0) Aalyss of real uderkeel clearace for Śwoujśce Szczec waterway years ,6 0, ,4 0, ,2 0,1 0.1 v=6 v = k 6 k v=3 v = k 3 k le of of equal loss loss 0 Fg. 2. P(UKC<0) for partcular shps at speed 6 ad 3 kots le of equal loss ( ot acceptable, acceptable) Fg. 3. Results of smulato for shp Golde Ice whch eter Śwoujśce at water level = 509, wave heght m ad speed 6 kots le of equal loss ( ot acceptable, acceptable) Fg. 4. Results of smulato for shp Golde Ice whch eter Śwoujśce at water level = 509 ad wave heght m at speed 3 kots Zeszyty Naukowe 32(104) z

5 Marta Schoeech, Sylwa Sokołowska Itegrated system for dyamc uderkeel clearace evaluato O the bass of probablstc model for UKC determato, Martme Traffc Egeerg Team from Mare Uversty of Szczec has created a tegrated system for UKC evaluato. System was bult as a tegrated tool whch cossts of model for UKC calculatg, decso model ad commucato module. The ma algorthm of tegrated system s based o probablstc method for UKC evaluato. I system program executo tme was creased, moreover, wave ad sedmetato model was rebult. System used cluster for calculato, whch ma parameters are [6]: total logcal core umber: 40; total RAM: 40 GB. Operatg system stalled o each cluster ode s detcal Deba GNU/Lux dstrbuto. Addtoally lbrary used MPICH 2 techology. Ma advatages of MPI stadard are [6]: good effectveess o multprocessors archtectures; great amout of fuctos; good documetato; publc doma status. Fally system effcecy was mproved. Oe smulato probablstc model for uderkeel clearace evaluato s equal 52 s whle wth MPI o blockg techology t takes 5 s. Actually research for verfy system are carred out. Coclusos The model cofrms decsos whch were made by Port Captas or VTS operators. Mea probablty level of touchg the bottom durg shps passages wth legth over 180 m years Śwoujsce s equal 18. Itegrated system for UKC determato effcecy was mproved. Further research s eeded referece to verfcato case of level of groudg probablty by usg tegrated system for UKC evaluato Śwoujśce port that was o acceptable. Refereces 1. MOES J., ROSSOUW M., BROPHY M., VAN LOON F.: Mmum Safe Uderkeel Clearace Port Etrace Chaels. PIANC, Sydey ERYUZLU N.E., CAO Y.L., D'AGNOLO F.: Uderkeel Requremets for Large Vessels Shallow Waterways. PIANC Proceedgs 28 th Iteratoal Cogress, Sevlle O BRIEN T.: Experece Usg Uderkeel Clearace Predcto Systems. The 2 d IHMA Cogress Professoalsm Ports, Duba SCHOENEICH M.: Probablstc method ad decso support system of shps uderkeel clearace evaluato etrace to the ports. Proc. of the 16 th Iteratoal Symposum o Electrocs Traffc ISEP, Ljublaa DOMAŃSKI C., PRUSKA K.: Neklasycze metody statystycze, rozdz. 8. Metody bootsrapowe. PWE, Warszawa DUCZKOWSKI M.: Dyamc uderkeel clearace predcto mplemetato o computer cluster. Master thess, Martme Uversty, Szczec Scetfc Jourals 32(104) z. 2