441kw600hp拖網(wǎng)漁船總體設(shè)計(jì)載魚(yú)量70噸

大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)目錄值為最大彎矩所在，所以：其中：因此，最大應(yīng)力為且QUOTE得出：因此，橫向強(qiáng)度符合要求。取L=35.40m取t=8m取t=7m取t=8m取b=1000mm取t=10mm取t=8m取t=7m取b=1000mm取t=9mm取b=300mm取t=9mm取t=7mm取t=11mm取b=700mm取b=450mm取t=8mm取s=500mm取t=7mm取δ=50mm取δ=40mm取t=7mm取t=6mm取t=9mmA=29cm2取t=8mm取t=7mm取h=400mm取t=7mm取t=9mm取h=1000mm取h=1000mm取t=8mm取t=8mm取t=7mm取t=7mm取t=7mm取t=7mm取t=7mm取b=70mm取h=250mm取b=250mm取t=8mm取h=200mm取s=500取Φ=108×8取l=2.5m取t=5mm取t=7mm取t=9mm取h=500mm取t=8mm取t=10mm取t=13mm取t=18mm取t=7mm取t=6mm取t=5mm取t=10mm取t=7mm取t=6mm取t=5mm取t=5mm取t=5mm取t=5mm取t=5mm取t=9mm取t=9mm取t=9mm大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)第七章螺旋槳設(shè)計(jì)第七章螺旋槳設(shè)計(jì)7.1拖網(wǎng)漁船主要參數(shù)總長(zhǎng)設(shè)計(jì)水線長(zhǎng)垂線間長(zhǎng)型寬 設(shè)計(jì)吃水 排水體積 排水量 方形系數(shù) 棱形系數(shù)槳軸中心線距基線 主機(jī)功率功率 主機(jī)轉(zhuǎn)速 軸系傳遞效率7.2船體有效功率計(jì)算（艾亞法）表7-1艾亞法求有效功率計(jì)算表水線長(zhǎng)Lw136.800寬度吃水比系數(shù)B/T2.667垂線間長(zhǎng)Lpp34.000方形系數(shù)Cb0.536寬度B7.200浮心縱向位置Xc-1.103吃水T2.700L/△1/34.763排水量（海水）△364t△0.6443.537v/(L0.5)0.8820.9701.0591.1471.235速度v（kn）1011121314傅汝德數(shù)0.2820.3100.3380.3660.394標(biāo)準(zhǔn)船型系數(shù)Co值查阻力圖7-3342306246198158標(biāo)準(zhǔn)方形系數(shù)Cbc查阻力表7-50.6050.5680.5520.5420.534實(shí)際Cb（肥或瘦）%11.4055.6342.901.11-0.375Cb修正（%）瘦(Kbc)查表（7-6）8.5905.8102.9601.050肥Cb修正數(shù)量△129.37817.7797.2822.079-0.952已修正Cb之C1371.378323.78253.282200.079157.048B/T修正（%）-3.573-3.57-3.573-3.573-3.573B/T修正數(shù)量△2-13.271-11.57-9.051-7.149-5.612已修正B/T之C2358.107312.21244.231192.930151.437標(biāo)準(zhǔn)Xc，%L,船中前或后(查表7-5）-1.620-2.180-2.440-2.505-2.563實(shí)際Xc，%L,船中前或后-1.103-1.103-1.103-1.103-1.103相差Xc，%L,在標(biāo)準(zhǔn)者前或后-0.517-1.077-1.337-1.402-1.460Xc修正（%）(查表7-7)3.3008.40014.00016.40019.600Xc修正數(shù)量-11.818-26.23-34.192-31.640-29.682已修正Xc之C3346.290285.98210.039161.289151.437長(zhǎng)度修正（%）0.0560.0560.0560.0560.056長(zhǎng)度修正數(shù)量19.37616.00211.7539.0258.473已修正長(zhǎng)度C4365.666301.99221.791170.314159.910Vs*Vs*Vs10001331172821972744Pe（Kw）881412494135497.3推進(jìn)因子的決定（漢克歇爾公式）伴流分?jǐn)?shù)：推力減額分?jǐn)?shù)：船身效率：相對(duì)旋轉(zhuǎn)效率：7.4可以達(dá)到的最大航速計(jì)算利用程序計(jì)算采用MAU4葉漿圖譜進(jìn)行計(jì)算。取功率儲(chǔ)備10%，軸系效率：則螺旋槳敞水收到馬力：PD=544.6hp根據(jù)MAU4-40，MAU4-55，MAU4-70的SqrtBp-δ圖譜列表計(jì)算。表7-2按圖譜設(shè)計(jì)的計(jì)算表假定航速V/kn11121314VA=V(1-ω)/kn8.9989.81610.63411.452Bp=N*PD0.5/VA2.543.238298934.785415728.4768489523.6608435SqrtBp6.575583545.897916215.3363703914.86424131MAU4-40δ73.116248167.023227461.8675945157.4484806P/D0.6860.7230.7520.791η00.6090.6290.6490.666PTE(hp)339.925131351.088518362.2519049371.740784PE(hp)MAU4-55δ72.14403266.132029361.0449501656.6845966P/D0.740.7620.8050.847η00.590.6120.6350.655PTE(hp)329.319914341.599639354.4375341365.600921PE(hp)MAU4-70δ71.227161665.291564860.2691367355.9641984P/D0.5910.6120.6350.655η00.5650.5870.6050.623PTE(hp)315.36568327.645406337.6924537347.739502圖7-1螺旋槳要素的確定表7-3確定最佳要素MAUVmax/knδP/Dη0D/m4-4012.1369.8070.6260.5861.4624-5512.269.6760.7030.5651.4494-7012.24669.930.6930.5311.4377.5空泡校核按柏利爾空泡限界線中商船上限線，計(jì)算不發(fā)生空泡的最小展開(kāi)面積比。 漿軸沉沒(méi)深度=T-Zp=2.661m -=+γ-=12883kgf/m2 計(jì)算溫度t=15℃、=174kgf/m2、PD=523.8hp、ρ=104.63kgf*s2/m4表7-4空泡校核結(jié)果Vmaxkn12.1312.212.246VA=0.5144Vmax(1-ω)m/s5.1040516965.133506245.152862(0.7πND/60)2(m/s)2580.8615751570.577542561.1661V0.7R2=VA2+(0.7πND/60)2(m/s)2606.9129189596.930428587.7181σ0.7R=(P0-Pv)/0.5ρV0.7R20.3892755030.395785370.401989τc（查柏利爾空泡限界圖）0.1570.1580.159T=PD*η0*75/VAkgf4689.061524495.083184208.714AP=T/0.5ρV0.7R2τcm20.9406621440.911025850.860908AE=AP/(1.067-0.229P/D)m21.0184227981.005532860.947821AE/A0=4AE/πD20.6069650870.610084290.584713從圖上讀出螺旋槳的最佳要素：P/D=0.70、=0.553、D=1.444、Vmax=12.23、AE/A0=0.606、P=1.0247.6強(qiáng)度校核按2001年《規(guī)范》校核及,(見(jiàn)表7-5)，應(yīng)不小于按下式計(jì)算之值：計(jì)算功率：Ne=582hpAd=AE/AO=0.606P/D=0.709ε=8°G=7.6g/cm3N=ne=450r/min=0.226DAd/(0.1Z)=0.494m=0.7212=0.357m=0.9911=0.490m表7-5強(qiáng)度校核計(jì)算表項(xiàng)目單位數(shù)值0.25R0.60R弦長(zhǎng)bm0.356820.49036K1634207K2250151K31410635K4434A1=D/P(K1-K2D/P0.7)+K3D/P0.7-K42380.3977852.8250134Y=1.36A1Ne/(Zbne)2933.5165764.7811668K58223K63412K74165K8380330A2=D/P(K5+K6ε）+K7ε+K81206.97681017.735142X=A2GAdne2D3/(1010Zb)0.2377120.145856316材料系數(shù)K1.381.38t=(Y/(K-X))0.5mm50.67648324.89348668MAU標(biāo)準(zhǔn)槳葉厚度t'mm55.24211831.48439673校核結(jié)果不滿足要求滿足要求實(shí)取槳葉厚度mm55.24231.484實(shí)際槳葉厚度按t1.0R=0.0035D=5.055mm與t0.25R=55.242mm連直線決定：大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)第七章螺旋槳設(shè)計(jì)7.7螺距修正轂徑比dn/D=0.18，此值與MAU槳標(biāo)準(zhǔn)轂徑比相同，故對(duì)此項(xiàng)無(wú)需螺距修正。由于實(shí)際槳葉厚度大于MAU槳標(biāo)準(zhǔn)厚度，故需因厚度差異進(jìn)行螺距修正。設(shè)計(jì)槳（t/b)0.7R=0.034標(biāo)準(zhǔn)槳（t/b)0.7R=0.0551-s=30.866VA/(NP) =0.67Δ(t/b)0.7R=-0.01Δ(P/D)=0.009修正后P/D=0.7097.8重量及慣性矩計(jì)算(1)螺旋槳總重 ①槳葉重量(kg) 材料重量密度γ=7600.000kgf/m3槳葉最大寬度=0.494m槳葉重量(kgf) =224.071kgf②槳轂重量(kg) 由螺旋槳圖繪制完成后進(jìn)行 軸榖配合錐度K=1/13=0.077 榖長(zhǎng)=0.360m槳軸中央處軸徑=0.145m槳榖直徑d=0.260m/d=0.557 榖重量=100.236kgf③螺旋槳總重=324.307kgf(2)螺旋槳總慣性矩 槳葉最大寬度=0.494 整個(gè)螺旋槳的慣性矩I=319.616(kgf·cm·s2)7.9敞水特性曲線的確定由MAU4-40，MAU4-55，P/D=0.6，P/D=0.7的敞水性征曲線內(nèi)插得到MAU4-56.4，P/D=0.709的敞水性征曲線，數(shù)據(jù)見(jiàn)表7-6。表7-6設(shè)計(jì)槳的敞水特性數(shù)據(jù)表MAU4-60.6P/D=0.709J0.0000.1000.2000.3000.4000.5000.6000.700KT0.3110.2870.2470.2070.1690.1290.0830.02910KQ0.3420.3190.2920.2640.2160.1780.1260.0837.10系柱特性計(jì)算由上表得J=0時(shí)，KT=0.317，KQ=0.0342計(jì)算功率Ne=582hp，系柱推力減額分?jǐn)?shù)=0.040 主機(jī)轉(zhuǎn)矩Q=926.282kgf·m 系柱推力T=5840.524kgf 螺旋槳轉(zhuǎn)速N=385.344rpm 7.11螺旋槳計(jì)算總結(jié)螺旋槳直徑D=1.444m螺距比P/D=0.709型式MAU葉數(shù)Z=4盤(pán)面比0.606縱傾角ε=8°螺旋槳效率=0.553設(shè)計(jì)航速=12.23kn轂徑比=0.180旋向右旋轉(zhuǎn)速450r/min材料鋁鎳青銅重量324.307kgf慣性矩319.616kgf·cm·s27.12螺旋槳型值計(jì)算表7-7伸張輪廓型值表（單位：mm）r/R0.951.0母線到隨邊AH13816519221523724625425924020886母線到導(dǎo)邊AJ19121923925125324923920112467-最大葉片寬b329384431467490495493460364275-葉片最厚t59524539322825181285導(dǎo)邊到最厚處距離105123138152171188198209178138-表7-8葉切面型值表大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)第八章結(jié)論與建議 第八章結(jié)論與建議大學(xué)四年系統(tǒng)的專(zhuān)業(yè)學(xué)習(xí)，在為期三個(gè)月的畢業(yè)設(shè)計(jì)中逐一被實(shí)踐。畢業(yè)設(shè)計(jì)是一次專(zhuān)業(yè)知識(shí)的綜合運(yùn)用，個(gè)人能力的具體檢驗(yàn)。在這樣的實(shí)踐演練中能夠培養(yǎng)我的思考及動(dòng)手的能力，對(duì)設(shè)計(jì)者來(lái)說(shuō)是一次難得的機(jī)會(huì)。通過(guò)這次的畢業(yè)設(shè)計(jì)，讓我對(duì)船舶總體設(shè)計(jì)有了初步并且較全面的了解，并且把以前所學(xué)習(xí)的專(zhuān)業(yè)知識(shí)系統(tǒng)地結(jié)合了起來(lái)，讓我收獲頗豐，在這里把我對(duì)這次設(shè)計(jì)的體會(huì)總結(jié)如下：1.穩(wěn)性往往是中、小型漁船設(shè)計(jì)中主要考慮的問(wèn)題。在設(shè)計(jì)中應(yīng)充分考慮該點(diǎn)。2.拖網(wǎng)漁船經(jīng)常在惡劣海況下作業(yè)，因此要求有良好的耐波性。3.自航時(shí)應(yīng)有較高航速，以便及時(shí)轉(zhuǎn)移漁船。4.艉部要有較大的吃水，以獲到較高的推進(jìn)效率，避免飛車(chē)現(xiàn)象發(fā)生。5.保證有足夠?qū)挸ǖ臐O撈甲板。6.采用1-Cp法進(jìn)行型線變換一般是對(duì)水線以下的型線進(jìn)行改造。為了滿足設(shè)計(jì)船的型深、舷弧、布置等方面的具體要求，水線以上部分采取自行設(shè)計(jì)的方法。在繪制時(shí)要注意與水線以下部分的型線互相配合的問(wèn)題。6.在繪制總布置圖時(shí)，艙壁必須落在肋位上，否則會(huì)對(duì)船舶的穩(wěn)性不利。7.在螺旋槳計(jì)算過(guò)程中，采用了一個(gè)計(jì)算小軟件來(lái)完成，提高了計(jì)算效率和計(jì)算的準(zhǔn)確性。在螺旋槳繪圖及標(biāo)注部分，采用了更加規(guī)范的繪圖和標(biāo)注方法，基本符合機(jī)械制圖的繪圖要求。8.本次畢業(yè)設(shè)計(jì)還新增加了橫向強(qiáng)度校核，通過(guò)對(duì)拖網(wǎng)漁船橫向強(qiáng)度的計(jì)算，更好地保證了拖網(wǎng)漁船在安全性方面的要求。經(jīng)過(guò)這一段時(shí)間來(lái)的畢業(yè)設(shè)計(jì)，從設(shè)計(jì)者本人的觀點(diǎn)看，對(duì)學(xué)校和本專(zhuān)業(yè)的畢業(yè)設(shè)計(jì)提出以下幾點(diǎn)建議：希望學(xué)校以后能在學(xué)生做畢業(yè)設(shè)計(jì)的時(shí)候，提供更多的實(shí)際操作機(jī)會(huì)。希望學(xué)校能更加重視船舶專(zhuān)業(yè)發(fā)展，在實(shí)驗(yàn)設(shè)備以及其它各方面能給予進(jìn)一步的支持。希望學(xué)校能多增添一些比較新的船舶資料。最后，衷心地感謝老師對(duì)我的指導(dǎo)和幫助并且希望我校的船舶專(zhuān)業(yè)越辦越好，希望海洋大學(xué)的明天會(huì)更加美好。大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)致謝致謝經(jīng)過(guò)了三個(gè)多月忙碌而又充實(shí)的學(xué)習(xí)和生活，本次畢業(yè)設(shè)計(jì)即將結(jié)束。從填寫(xiě)開(kāi)題報(bào)告到最后編寫(xiě)全船說(shuō)明書(shū)的過(guò)程將大學(xué)四年的專(zhuān)業(yè)知識(shí)復(fù)習(xí)鞏固了一遍，我對(duì)一些專(zhuān)業(yè)知識(shí)又有了新的認(rèn)識(shí)。在此次畢業(yè)設(shè)計(jì)的過(guò)程中，我得到了眾多老師的耐心指導(dǎo)和同學(xué)的熱情幫助。尤其要對(duì)我的指導(dǎo)教師黃亞南老師表示衷心地感謝！黃老師在整個(gè)畢業(yè)設(shè)計(jì)過(guò)程中給予了我很大的幫助和耐心細(xì)致的指導(dǎo)，很多細(xì)節(jié)性的錯(cuò)誤都得以改正。使得我的畢業(yè)設(shè)計(jì)可以按時(shí)保質(zhì)地完成。在各位老師和同學(xué)的指導(dǎo)和幫助下使我順利的完成本次設(shè)計(jì)，在此一并向他們表達(dá)我最誠(chéng)摯的謝意。大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)參考文獻(xiàn)參考文獻(xiàn)[1]DagPike．FishingBoatsandtheirEquipment．FishingNewsLtd，1979[2]賈復(fù)．漁船設(shè)計(jì)．大連：農(nóng)業(yè)出版社，1995[3]王世連，劉寅東．船舶設(shè)計(jì)原理．大連：大連理工大學(xué)出版社，2001[4]中華人民共和國(guó)農(nóng)業(yè)部漁船檢驗(yàn)局．鋼質(zhì)海船建造規(guī)范．北京：國(guó)防工業(yè)出版社，1998[5]顧敏童．船舶設(shè)計(jì)原理．上海：上海交通大學(xué)出版社，2001[6]楊永謙，茆文玉，翁士綱．船體制圖．哈爾濱：哈爾濱工程大學(xué)出版社，1995[7]盛振邦，楊尚榮，陳雪深．船舶靜力學(xué)．上海：上海交通大學(xué)出版社，1998[8]K.J.Rawson．BasicShipTheory．Longman，1976[9]農(nóng)業(yè)部水產(chǎn)司漁業(yè)機(jī)械行業(yè)協(xié)會(huì)．中國(guó)鋼質(zhì)海洋漁船圖集．上海：科技出版社，1991[10]盛振邦，劉應(yīng)中．船舶操縱與搖擺．上海：上海交通大學(xué)出版社，2003[11]王杰德，楊永謙等．船體強(qiáng)度與結(jié)構(gòu)設(shè)計(jì)．北京：國(guó)防工業(yè)出版社，1998[12]盛振邦，劉應(yīng)中．船舶阻力．上海：上海交通大學(xué)出版社，2003[13]孫文志．漁船螺旋槳設(shè)計(jì)，大連：五洲出版社，1998[14]盛振邦，劉應(yīng)中．船舶推進(jìn)．上海：上海交通大學(xué)出版社，1995[15]StaffMembers．FishingportsandMarkets．FishingNewsLtd，1979大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)文獻(xiàn)綜述附錄Ⅰ文獻(xiàn)綜述拖網(wǎng)漁船屬于過(guò)濾性的運(yùn)動(dòng)漁具，在拖拽過(guò)程中，將各種魚(yú)蝦等驅(qū)集入網(wǎng)，使水慮過(guò)網(wǎng)，漁獲物不能通過(guò)而達(dá)到捕撈魚(yú)獲的目的。[1]拖網(wǎng)漁船是漁船中主要船型之一。一些海洋漁業(yè)發(fā)達(dá)的國(guó)家，50％以上漁獲物為拖網(wǎng)漁船所捕得。拖網(wǎng)的種類(lèi)常見(jiàn)的為底拖網(wǎng)，漁船拖拽網(wǎng)具在海底拖拽化形，魚(yú)被攔入網(wǎng)內(nèi)，通常所指的拖網(wǎng)漁船，多為底拖網(wǎng)漁船。除底拖網(wǎng)漁船外，還有中層拖網(wǎng)或稱變水層拖網(wǎng)，網(wǎng)具不在海底拖拽而在海水中層拖拽。底拖網(wǎng)用以捕撈棲游于海底的魚(yú)類(lèi)。中層拖網(wǎng)則捕撈浮游于海洋中上層的魚(yú)類(lèi)。1發(fā)展歷史：漁船簡(jiǎn)史主要指用以捕撈和采收水生動(dòng)植物的船舶。但也包括現(xiàn)代捕撈生產(chǎn)的一些輔助船只，如進(jìn)行水產(chǎn)品加工、運(yùn)輸、養(yǎng)殖、資源調(diào)查、漁業(yè)指導(dǎo)和訓(xùn)練以及執(zhí)行漁政任務(wù)等的船舶。漁船，是海洋漁業(yè)的基本生產(chǎn)工具。從近代各地出土文物考證和歷代編修的史志記載表明，我國(guó)遠(yuǎn)在新石器時(shí)代前早就出現(xiàn)了“舟”（船），不過(guò)遠(yuǎn)古原始時(shí)代的“舟”，都是采用比較粗長(zhǎng)的樹(shù)木雕鑿而成的“獨(dú)木舟”。追溯歷史可以從很多古書(shū)中覓到，早在幾千年前人們?cè)谏a(chǎn)生活實(shí)踐活動(dòng)中就有利用“舟楫之便”、“以船為車(chē)”、“以楫為馬”等記載，這說(shuō)明人類(lèi)早就開(kāi)始使用木舟（木船）了。從當(dāng)時(shí)社會(huì)背景分析，早期的木舟是作為內(nèi)陸江河湖泊漁獵、航運(yùn)和載人所用的一種必需工具?！蔼?dú)木舟”的綿延年代十分久長(zhǎng)，據(jù)有關(guān)資料記載，到春秋戰(zhàn)國(guó)的晚期才出現(xiàn)用木板拼裝船（拼板船），后發(fā)明了船上用的風(fēng)帆（風(fēng)篷）。隨著社會(huì)的發(fā)展使原始狹小的“獨(dú)木舟”，逐漸向?qū)挸ǖ摹捌窗宕蹦Ｊ窖葑?。[2]拖網(wǎng)漁船簡(jiǎn)史

中國(guó)早在明代就有了“牽風(fēng)”等船型的風(fēng)帆拖網(wǎng)漁船。19世紀(jì)末西歐首先研制了機(jī)動(dòng)拖網(wǎng)漁船，隨后世界各地逐步開(kāi)始制造。20世紀(jì)50年代英國(guó)又研制成尾滑道拖網(wǎng)漁船，已成為世界上拖網(wǎng)漁船的主要船型。中國(guó)于1905年由張謇從德國(guó)引進(jìn)了國(guó)內(nèi)第一條機(jī)動(dòng)拖網(wǎng)漁船“福海號(hào)”；1912年自行建造了第一艘鋼質(zhì)舷拖漁船。50年代初,中國(guó)在自行設(shè)計(jì)制造185千瓦拖網(wǎng)漁船的同時(shí)，曾將部分風(fēng)帆漁船加裝柴油機(jī)后改為機(jī)帆拖網(wǎng)漁船。70年代已開(kāi)始成批建造尾滑道拖網(wǎng)漁船。

2拖網(wǎng)漁船特點(diǎn)及相關(guān)要求

：拖網(wǎng)漁船拖力較大，一般為3～5噸，大型拖網(wǎng)船可達(dá)30噸。拖網(wǎng)速度一般為3～6海里/小時(shí),自由航速為10～14海里/小時(shí)。為充分發(fā)揮主機(jī)功率,增加拖力，常使用可調(diào)螺距螺旋槳、導(dǎo)管螺旋槳和減速齒輪箱等設(shè)備。上層建筑緊湊，以減少受風(fēng)面積、增強(qiáng)抗風(fēng)力。作業(yè)甲板寬敞，便于起、放網(wǎng)操作和堆放網(wǎng)具；甲板上裝有拖網(wǎng)絞機(jī)等捕撈機(jī)械。一般都設(shè)有保冷隔熱魚(yú)艙，近海漁船常用冰或冰和制冷結(jié)合的方法保藏漁獲物；遠(yuǎn)洋漁船大多在船上加工和凍結(jié)貯藏漁獲物。船上一般配有雷達(dá)、勞蘭、探魚(yú)儀等助漁導(dǎo)航儀器。[3]基于拖網(wǎng)漁船的特點(diǎn)，因而在性能與布置上有一定的要求：由于拖網(wǎng)漁船經(jīng)常在惡劣海況下作業(yè)，因此要求有良好的耐波性，即橫搖、縱搖和起伏運(yùn)動(dòng)緩和，加速度要小，在迎浪時(shí)能騎浪而不鉆浪。在自航時(shí)能有較高的航速，以便能及時(shí)轉(zhuǎn)移漁場(chǎng)。而在作業(yè)時(shí)又要有較大的拖力，拖網(wǎng)航速視所捕撈魚(yú)類(lèi)的不同而不同，通常拖拽速度在3—4.5節(jié)左右。艉部要有較深吃水，以容納大直徑的螺旋槳求得較高的推進(jìn)效率。同時(shí)能是螺旋槳埋入較深的水中，避免在風(fēng)浪中螺旋槳出水。具有良好的航向穩(wěn)定性，以保持正常的網(wǎng)形，從而提高漁撈效果，減少網(wǎng)具的損壞。要求有足夠?qū)挸ǖ臐O撈甲板面積，以便于布置起放網(wǎng)機(jī)械設(shè)備與能順利地進(jìn)行漁撈操作。特別在長(zhǎng)度上應(yīng)有足夠的長(zhǎng)度，以便盡可能一次將袖網(wǎng)拉上甲板。同時(shí)應(yīng)將全部漁撈操作盡可能集中于一處，以便互相呼應(yīng)，密切配合。由于在起網(wǎng)時(shí)為了網(wǎng)口附近的魚(yú)獲不致逃失，常在起網(wǎng)時(shí)要加大拖速，這也就直接增大了網(wǎng)具阻力。為此，要求有一功率強(qiáng)大的起網(wǎng)絞車(chē)，并希望有較大的起網(wǎng)線速度，以盡量縮短起網(wǎng)時(shí)間。[4]3拖網(wǎng)漁船分類(lèi)：按作業(yè)方式可分雙拖、單拖和兼作漁船。雙拖漁船

作業(yè)時(shí)兩船平行合拖1頂拖網(wǎng)。一般作業(yè)甲板在船的中前部，上層建筑在中后，機(jī)艙在后，魚(yú)艙在前。船長(zhǎng)20～40米，主機(jī)功率60～1000千瓦。單拖漁船

由單船拖曳網(wǎng)具，依靠網(wǎng)板或桁桿張開(kāi)網(wǎng)口進(jìn)行作業(yè)。單拖漁船按船上拖曳部位的不同又可分為：①舷拖漁船。在舷側(cè)放網(wǎng)、拖網(wǎng)和起網(wǎng)，靠網(wǎng)板張開(kāi)網(wǎng)口進(jìn)行作業(yè)。作業(yè)甲板在船的中前部，拖網(wǎng)絞機(jī)置于駕駛室前下方，舷側(cè)前后設(shè)置網(wǎng)板架，上層建筑集中于中后部，船員住室置于長(zhǎng)尾樓和首樓。這種漁船因拖網(wǎng)負(fù)重而使船體橫傾，影響船舶穩(wěn)性和安全，不宜進(jìn)行深海遠(yuǎn)洋作業(yè)。早期在世界上使用很廣，但從20世紀(jì)50年代開(kāi)始已逐漸由尾拖漁船所取代。②尾拖漁船。在船尾進(jìn)行拖網(wǎng)和起、放網(wǎng)，靠網(wǎng)板張開(kāi)網(wǎng)口進(jìn)行作業(yè)。上層建筑一般設(shè)在船前部，尾部?jī)蓚?cè)設(shè)有網(wǎng)板架。作業(yè)甲板設(shè)于中后部，適合浪大水深的水域作業(yè)。尾滑道拖網(wǎng)漁船的船尾設(shè)有起、放網(wǎng)具用的傾斜滑道，是對(duì)原有單拖漁船的重大革新。大、中型船一般長(zhǎng)60～120米,功率1500～7000千瓦。上甲板與尾部滑道連通，為作業(yè)甲板，起、放網(wǎng)在尾部進(jìn)行。其優(yōu)點(diǎn)是：起、放網(wǎng)時(shí)漁船不必轉(zhuǎn)向，起網(wǎng)時(shí)網(wǎng)衣直接由絞機(jī)拖上甲板，故起網(wǎng)速度快、勞動(dòng)強(qiáng)度低；操作時(shí)受風(fēng)浪影響較小，可增加放網(wǎng)次數(shù)，且較安全；作業(yè)甲板寬敞，可配置底層、中層等多種拖網(wǎng)進(jìn)行輪流作業(yè),并能使用大型網(wǎng)具和進(jìn)行深水拖網(wǎng);漁獲物可直接卸到下層甲板間，使起、放網(wǎng)和處理漁獲物互不干擾；漁獲物不受日曬雨淋，有利保持質(zhì)量。其缺點(diǎn)是起網(wǎng)時(shí)網(wǎng)具因通過(guò)滑道而磨損較大。一般以單拖作業(yè)為主，也可進(jìn)行雙拖作業(yè)。③桁拖漁船。以竹、木桿或鋼桿等作為桁架,從兩舷伸出船外,用于固定網(wǎng)具進(jìn)行拖曳捕撈。一般為幾十總噸的小型漁船，配有較簡(jiǎn)單的絞綱機(jī)械。多在近海及內(nèi)陸淺水區(qū)作業(yè)，以捕蝦類(lèi)、蟹類(lèi)為主。兼作漁船

以拖網(wǎng)捕撈為主,兼作圍網(wǎng)、流刺網(wǎng)、釣捕等捕撈作業(yè)的漁船?？筛鶕?jù)漁場(chǎng)的資源情況隨時(shí)調(diào)換網(wǎng)具作業(yè)，以增加產(chǎn)量。小型船一般長(zhǎng)30米左右，單甲板型。中型拖網(wǎng)兼作漁船多為雙甲板型，長(zhǎng)首樓，尾部為作業(yè)甲板，設(shè)置尾滑道，有的裝有2臺(tái)卷網(wǎng)機(jī),分別用于底層拖網(wǎng)和中層拖網(wǎng)。圍網(wǎng)存放在尾部專(zhuān)設(shè)的網(wǎng)艙內(nèi)或尾滑道上方的網(wǎng)臺(tái)上。當(dāng)進(jìn)行圍網(wǎng)作業(yè)時(shí)，用圍網(wǎng)起網(wǎng)機(jī)在舷側(cè)起網(wǎng)；有的船在首、尾部裝有側(cè)推裝置，以利操作。

4拖網(wǎng)漁船發(fā)展現(xiàn)狀及發(fā)展趨勢(shì)：當(dāng)代大型拖世界上海洋漁船的發(fā)展受到兩個(gè)方面的影響，一是200海里專(zhuān)屬經(jīng)濟(jì)區(qū)的劃分；二是能源緊張現(xiàn)象的出現(xiàn)。由于200海里專(zhuān)屬經(jīng)濟(jì)區(qū)的劃分，各國(guó)為了加強(qiáng)本國(guó)近海漁業(yè)資源的開(kāi)發(fā)利用，船長(zhǎng)在40米以下的小型漁船得到了迅速發(fā)展，并且具備以下特點(diǎn)：一、多用途：為了發(fā)揮使用效率，可以進(jìn)行多種作業(yè)。這不僅從布置上進(jìn)行了考慮，而且從設(shè)備上也配置齊全，如拖圍兼作的小型漁船，在船上拖網(wǎng)絞車(chē)與圍網(wǎng)起網(wǎng)機(jī)是齊備的。二、注意節(jié)能：小型的拖網(wǎng)漁船上不僅可使用可調(diào)螺距螺旋槳加導(dǎo)管以提高推進(jìn)效率；而且機(jī)帆裝置也在流行起來(lái)，為防止重心過(guò)高，其桅則采用鋁合金或玻璃鋼制成。另外，為減少船體阻力，在型線上也有新的發(fā)展，漁船上采用球鼻首在國(guó)外已較為普遍，甚至在兩柱間長(zhǎng)不足20米的小型拖網(wǎng)漁船也配置球鼻艏。三、重視安全性：為確保小型漁船在海上的人命，一些國(guó)家都相繼制定了一些適用于小型漁船的法規(guī)；如日本在70年代初期就制定了船長(zhǎng)下限為15米的鋼質(zhì)漁船建造標(biāo)準(zhǔn)；英國(guó)則對(duì)登記長(zhǎng)度在12米以上的漁船穩(wěn)性制定了較詳細(xì)的法規(guī)，同時(shí)對(duì)24.4米以下的鋼質(zhì)、木質(zhì)及玻璃鋼漁船頒布了建造法規(guī)。除此之外，一些電子設(shè)備，如彩色雷達(dá)、聲納、視頻測(cè)探記錄儀、遙控自動(dòng)駕駛儀、甚高頻無(wú)線電、單邊帶無(wú)線電、自動(dòng)測(cè)向儀、衛(wèi)星導(dǎo)航儀、氣象傳真接收儀、風(fēng)速風(fēng)向指示儀以及勞蘭接受儀等等也用之于小型漁船。由于200海里專(zhuān)屬經(jīng)濟(jì)區(qū)的劃分，一些海洋漁業(yè)發(fā)達(dá)的國(guó)家為了向遠(yuǎn)洋漁場(chǎng)進(jìn)行作業(yè)，因此大、中型拖網(wǎng)漁船，特別是大型拖網(wǎng)漁船（兩柱間長(zhǎng)在60米以上）也有所發(fā)展。因?yàn)榇笮突耐暇W(wǎng)漁船可長(zhǎng)時(shí)間的在距離基地港較遠(yuǎn)的漁場(chǎng)作業(yè)，對(duì)復(fù)雜的氣象條件適應(yīng)性強(qiáng)，同時(shí)可在船上布置較多加工設(shè)備。如蘇聯(lián)多年來(lái)一再增加總長(zhǎng)達(dá)102米的“SuperAtlantik”型的大型艉拖網(wǎng)漁船的數(shù)量。其他如美國(guó)、西班牙、意大利、加拿大、法國(guó)、荷蘭、等國(guó)都分別建造了一些總廠為70米左右的大型漁船，多為拖網(wǎng)與圍網(wǎng)漁船。這些事實(shí)說(shuō)明，大型拖網(wǎng)漁船有進(jìn)一步發(fā)展的趨勢(shì)。網(wǎng)漁船長(zhǎng)度可達(dá)100米，船上裝有完備的魚(yú)產(chǎn)品加工設(shè)備?？偨Y(jié)：綜合所查文獻(xiàn)資料可總結(jié)拖網(wǎng)漁船的主要發(fā)展方向?yàn)椋孩佥^多建造經(jīng)濟(jì)實(shí)用的中、小型拖網(wǎng)船，并重視遠(yuǎn)洋深水拖網(wǎng)漁船的研制開(kāi)發(fā)；②采取節(jié)能措施，如改進(jìn)柴油機(jī)性能、增大螺旋槳直徑、降低轉(zhuǎn)速以提高推進(jìn)效率，改良船型，采用主機(jī)軸帶發(fā)電機(jī)和利用余熱；③配備先進(jìn)探魚(yú)及導(dǎo)航儀器；④研制拖網(wǎng)自動(dòng)控制系統(tǒng)等。參考文獻(xiàn)[1]賈復(fù).漁船設(shè)計(jì).農(nóng)業(yè)出版社.1987年07月[2]唐志拔.海船發(fā)展史話.哈爾濱工程大學(xué)出版社.2008年04月[3]漁船演變史.2008年04月[4]賈復(fù).漁船設(shè)計(jì).農(nóng)業(yè)出版社.1987年07月大連海洋大學(xué)本科畢業(yè)設(shè)計(jì)外文原文及翻譯附錄Ⅱ外文原文及翻譯外文：DevelopmentofJapaneseSterntrawlersWhentheJapanesetrawlerfisheriesweresearchingfornewoverseasfishinggroundstoexpandoperationsbeyondtheregionoftheEastChinaSeaandJapanesewaters,wherefishinguntilthenhadbeenprosperous,astudyofEuropeanstern-trawlingtechniqueswasfirstundertaken.In1955thetrainingship,UmitakeMaru,ofTokyoUniversityofFisherieswasthenbuilt,followingcloselythedesignofaEuropesterntrawler.In1957,theTaiyoMaruNo.51,alargertrawler,wasbuiltbyaJapanesefirm,butasthedataonstern-trawlerconstructionwasstillinsufficientitwasplannedthatthevesselwouldservebothasadeep-seatrawlerandasacarrierfortheAntarcticwhalingindustry.Thisdesignprovedsosuccessful,however,andsuchgoodresultswereobtainedbythetwovesselsintheNorthPacificandNewZealandwatersthatabout30sterntrawlersof1,500to2,500GTwerelaunchedbyJapanesefishingcompaniesduringtheyears1960to1963.ThesetrawlersnotonlyoperateinwatersofftheNorth-WestAfricancoastandtransporttheircatchtoJapan,butarealsorequiredtoprocessfrozenfishforexport,meetingthevariousconsumptionrequirementspeculiartotheimportingcountries.Largetrawlersweredevelopedwiththecapacityofoperatingforlongperiodsindistantwaters.Theywerefullyequippedwithfilletingmachineryandmealplanttoproducevariousfinishedproductswiththeminimumofwastage.In1964designsweresoimprovedinthe2,500to3,500GTrangethatadequatespacetoaccommodateessentialmaintenancepersonnelandequipmentwasavailable.Fromaneconomicaspectthelargerthetrawlerthelargermustbethecatchwhichcanonlybeacquiredfromdeepwaterfishinggrounds,entailingheavierdutytrawlwinches.Sterntrawlersof300GTwerealsobuiltbylesserJapanesefishingcompaniesforoperationmainlyintheNorthPacificutilizingapowerfultrawlwinchandmainengine.Theirsmallsizenaturallyrestrictedtheiroperationalrangeandtheyoperatedmoreefficientlyworkingco-operativelywithafactoryvesselratherthanasindividuals.Duetoseakeepingconsiderations,andhenceworkingconditionsaboard,itwasnecessarytoincreasetheirsizeto500GT.TYPEANDSIZEOFVESSELTheinitialconsiderationindesigningasternramptrawleristhepositionofthemainengineaftoramidships.Japanesetrawlersoperatefarfromtheirhomeportsandthereforetheratiooffishingtovoyagetimeneedstobeconsideredwhenfixingtherefrigeration,refrigerationhold,fueloil,fresh-watertankandprovisionstorecapacities.Asufficientafterdraftforallloadingconditionsmustalsobeconsidered.Tosatisfytheseconditionsthefollowingarrangementisindicated:fatamid-shipforfishhold,forepeakanddoublebottomforfueloiltankandtheremainderengineroom.Thisisadescriptionoftheengineafttype.Aproblemisthelocationoftheenginecasingandfunnel.Alargeenginecasingwillreducethefishtreatmentspaceontheshelterdeckandacentre-linefunnelwillcomplicatethetrawl-winchlayout.Withtheexceptionoftheprototypevessel,theTaiyoMaruNo.51,thiswassolvedbyadoptingalayoutsimilartoawholefactoryship,thatistheenginecasingreducedtoaminimuminwayoftheshelterdeckorthecasingandfunneldividedlongitudinallyandsitedatthesidesofthedeck.Apartfromtheprototype,therefore,alllargeJapanesetrawlershavebeenbuiltwithengineanshelterdeckaft.TheblockcoefficientofJapanesetrawlersquotedisratherhigherthanothercountriesandthereistheattendantlossinspeed.Forvesselswhichfreezethewholeormostofthecatchonboard,excessivespeedisdetrimentaltoeconomicperformanceanditwouldseemquiteinordertoacceptsuchalowerfree-runningspeed,permittingeconomicalsavingsinfuelconsumption,greaterradiusofactionandabetterratiooffishtofuelcapacity.Atpresent,theeconomicjustificationoftheselargevessels,especiallyinregionswherethehighly-qualifiedtechnicalstaffrequiredonboardthevesselsarebeingcompetedforbyshore-basedindustries,requiresverycarefulconsiderationandemphasizetheneedformorereliableautomaticmachinery,fish-handingequipment.Shimizuproposestheadoptionofvesselsspecificallydesignedforaspecificfishinggroundtominimizetheequipmentrequired.Thisprincipleisnowgainingfavorinthedesignoffishingvesselsofsizeaboveabout130ft(40m)inlength,sincethevesselandgearcanbetailor-madeforspecificadverseweatherconditions,bottomconditions,depthofwaterandrangeofoperations.Manycasescouldbequotedwherethedesignofvesselshasbeenspoiledbyattemptingtocopeinthedesignwithtoomanyfishingpossibilities.Toovercomethetendencyforthelargerdeepseatrawlerstodrifttoleewardandcoursestabilityatlowtrawlingspeeds,lateralthrustunitsfittedatthebowandsternhavebeensuccessfullyemployed.ExperimentswithsuchunitsintheshipdivisionofNPLhaveshownthatspecialcaremustbetakeninsightingthelateraltunnelrequired.Fairingofthemouthsofthetunnelisrequired,particularlywhenthelinesofthevesselhaverapidcurvatureinthisregion.Ingeneral,JapaneselargesterntrawlershavelargerL/Bvaluesintherange5.7to6.0,whilstothercountriestendtotherange5.5to5.7,butthelatestfactorytrawlerofabout3,000GThasasmallerL/Bratiotoaccommodatefactoryequipment.TheblockcoefficientofJapanesetrawlersalsotendstobehigherwhencomposedondeadweight.Thismeansthatsomelossincomparativeship’sspeedisinevitable.Foreaseofslidinguptheotterboards,thetransomwasinclinedslightlyforward,butwiththeincreaseofdeep-seatrawling,thisslopehasbecomeverticaloreveninclinedaft,thuspermittingthetrawlnetwarptocomeupalmostverticallyontothetoprollerandsoavoidfayingonbulwarkroller.Theengineaftallowsaconstantafterdrafttobemaintainedalthoughithasbeennoticedthatthistypeofvesselsuffersfrompantingunderthecounterwhenthemid-shipholdisempty.Theincreaseintow-ropeforcerequiredhasatendencytoincreasetheenginepower,hencedecreasedpropellerrevolutionsandincreasedpropellerdiameter.Thisnecessitatesaraisingofthecounteranddecreasesthesternimmersionwhichincreasesthesusceptibilityofpaintinginheavyseas.Toavoidthis,eithertheafterdraftmustbeincreasedoraspade-typerudder,asintheBritishsterntrawlerRossValiant,mustbeintroduced.Tohelpthenet-haulingoperationtheafterendofthesternrampistosomeextentsubmerged,givingacorrespondingincreaseintotalshipresistance,butthisisfoundtobenegligible.TYPEOFENGINESFORPROPULSIONMostJapanesesterntrawlershavesingledirectenginesbutsomeEuropeantrawlersontheotherhandusediesel-electricpropulsivesystems.ThereishesitationinJapaninusingthissystembecauseofthefollowingreasonswhencomparedwithsingledirectengines:HigherinstallationcostsandfuelcostsLargerengineroomrequiredInsufficientworkingknowledgeandpracticalexperienceTheJapaneseFisheriesAgencyisproposingaprototypeguidancevesselwithdiesel-electricsystem.“FatherandSon”andothersystemarealsounderconsideration.MostJapanesetrawlersbuiltsince1953areequippedwithremotecontrolfromthewheelhousetotheengineroomandsomeareequippedwithautomaticsystemsforfueloilpurificationandrefrigeration.TheUKhasexperienceoflargestern-fishingfreezertrawlerswithenginesaft,enginesforwardandsplitdiesel-electric.Thepresenttrendistowardsasingleengineforwarddrivingacontrollablepitchpropeller,secondmostpopularisdiesel-electric.Ifacontrollablepitchpropellerisusedinthisclassofship,thereisconsiderablefuelsavingifitispossibletovarypropellerrpm.Furtheronthesubjectofpropulsioneconomics,carefulselectionofmachineryonabasisofmeasurementsmadeinserviceconditionscanmakeagreatdifferencetocosts:onepopularclassofmachinery(diesel-electricwasselectedonthebasisoftheoreticalestimatesandcomprised3×1,000hpengines;measurementatseashowedthatforfishingamaximumof1,200hpwasrequiredandthisclassofvessel,therefore,couldnotquitefishononeengine-twowereusuallyrun.Asaresultofthesemeasurements,thespecificationofsubsequentvesselshasbeenchangedto2×1,400hpengines,withconsequentsaving.TRAWLWINCHThetypeoftrawlrequired,whetheritbeelectricorelectro-hydraulicdrive,andinthelattercase,highorlowpressure,isdecidedbythecostandthewinchcharacteristics.Itisdifficult,therefore,toreachanydefiniteconclusionsastoabesttype.InitiallyelectricdrivewasusedandsincethenalmostallvesselshavebeenequippedwithACmotorsfortrawlwinches.TheACmotorasitstandsisunsuitableforthispurposeandlowpressureelectro-hydraulicdrivewasadopted.Withtheexpansionofdeepseatrawling,higherwinchwindingspeedswerenecessary.Toadaptthelowpressuresystemisnotsimplebecauseofthelargepumproomrequired,sorecentlyACKraemertypeelectricorhighpressureelectro-hydraulicsystemsareused.Thetrawlwinchcapacityiscalculatedfromthemaximumintendedtrawlingdepthandsizeofnet.Winchesofcurrentsterntrawlershavecapacitiesof12to23tons×295to197ft(90to60m)wirespeedsperminute.NOTESONGENERALEQUIPMENTWorkingdeckTheadvantageofhavingenginesaftisinprovidingampleworkingdecklengthifthedispositionoftheenginecasingcanbecorrectlyadjusted.Thedistancebetweentheupperedgeofthesternslipwaytothetrawlwinchissome100ft(32.8m)for1,500GTand130ft(42.7m)for3,000GTvessels.Toobtainthisthebridgemustbewellforwardand,consequentlygivingacentreofwindpressurewellforward,thishasthedisadvantageofproducingatendencytodrifttoleeward.Toovercomethistheworkingdecklengthforevenalargevesselisrestrictedtoabout100ft(32.8m).AccommodationspaceProcessingandrefrigerationequipmentoccupymuchspaceinJapanesedistant-watertrawlers.Thisequipmentdemandsalargercrewtooperateitthaniscommoninothercountries,soadequateaccommodationspaceisnecessary.Afactorytrawlerhasacrewcomplementof110to130,thereforeanyreductioninthisnumberbyadoptingautomaticcontrolsystemsisdesirable.Henceautomationandaccommodationshouldbestudiedasinterdependents.TrawlwinchoperationsMosttrawlwinchesaresideoperatedbutinseverallargetrawlerscontrolroomshavebeensituatedjustaftofthebridgewiththeclutchandbrakeoperatedbypneumaticremotecontrol.Dependingontheship’soperationalarea,mustbetakennottolosethenetbysnaggingonnaturalunderwaterprojections.Forthispurposeanalarmsystem,triggeredbyexcessivestrainonthewarpsandrecordedinthebridgeandcontrolroom,hasbeeninstalled.Thisisremotelyrecordedbyanoil-pressureorwireresistancestraingaugeatthetoprollerofthegallowsorontheropewayofthewarp.Thisisnowunderpracticalprovingtestsinalargesterntrawler.Onthequestionofwhethertohavewarpingendsonwinches,onemightnotetheverycomprehensivestudyoftheoperationofthewinchofalargesterntrawlercarriedoutbytheIndustrialDevelopmentUnitoftheWhiteFishAuthority(UK).Toavoidlosingfishingtime,highlight-hookspeedsareneedsforsomepartsoftheoperationofhandingthetrawl;atothertimes,heavypullsareneeded;therefore,ifthejobhastobedonebyhavingalotoflittleauxiliarywinchesscatteredaboutthedeck,andtheseareofthecommonconstant-torquehydraulictype,theyhavetobeofquitebighorsepower.Theideaiseconomiconlyifsophisticatedhydraulicsystemswithnearconstant-powercharacteristicsareadopted,otherwisetheuseofwarpingendsonthewinchisadvised.300-GTTRAWLERIn1960theJapanesegovernmentallowedtrawlerstooperateintheNorthPacificandtrawlersofsuchsmalldisplacementwereneglected.In1962,however,theChuyoMaruNo.5wasbuiltandhashadafavorablereception.Afterconsideration,themainenginewasfixedamid-shipandthelongfo’c’sleaccommodatedtheafterpartoftheengineroom,thiscausedareductioninworkingspacebutnotaccommodation.From1963to1965tenmoresterntrawlersof3,000GThavebeenbuilt,equippedwithmorepowerfulenginesandtrawlwinchwhencomparedwiththeship’ssizeandalsocontrollablepitchpropellers.Theseweredesignedasindependentmiddle-watertrawlers,withheavycatchesonshortvoyagetimes,andfishingperiod.Themainenginewas800to1,200hp.Fortheengineafttype,acompactenginewasessentialandsothegeareddieselwastheobviouschoice.Thecontrollablepitchpropellerandpowertrawlwinchenableasteadywinchrotationwhichisoil-pressure-drivenfromthemainengine.Basically,threetypeshavebeendeveloped:ShelterdeckEnginemid-shipwithlongfo’c’sleEngineaftwithlongfo’c’sleTheSankichiMaruNo.51,builtin1964,hasadiesel-electricpropulsiveunitwithtwothree-phasemotors,reductiongearingandacontrollablepitchpropeller.JAPANESEFACTORYTRAWLERSWithtrawlersbeingforcedtofishinmoredistantwaters,itwasnecessarytoincreasethesizeofvessel,toincreasethefishholdcapacityandtostillmaintainaneconomicproposition.Nowadays,inordertomaintainthefullediblestandardofthecatch,therelaybasesystem,whichhascometobethepossiblewithco-operationfromothernations,hasbeenestablished,andwhilstfishfordomesticconsumptioniswashedandthenfrozenwhole,fishforexportisprocessedalmosttofishblock.Non-processiblefishandfishoffalareprofitablyreducedtomeal.Forthispurpose,fullprocessingfactorytrawlersof3,000to3,500GT,equippedwithBaaderandmealplant,begantobebuiltby1963.EXAMINATIONOFFUTUREDEVELOPMENTSLargefactorytrawlersareexpensiveandcanmakenocommercialprofitunlesstheyarefullyutilizedbecauseoftheinstallationsandlargecrewrequired.Itappearsthatvesselsspeciallydesignedandequippedforaspecificfishinggroundmustbeconsidered.Thiswouldenableaminimumofequipmenttobeinstalled.Acarefulanalysisshouldbemade,therefore,ofthespecificareainrespectofdepthofwater,prevailingweatherandseaconditions,typesoffishandassociatedprocessingandthemarketingpossibilities.WagesandlivingstandardinJapanhaverisen,andbetteraccommodationmustbeprovidedbecauseofthelongperiodsatsea.Simplificationofhandlingvessels,fishingandfactoryoperationmustbestudiedseriously.Thisiswithou