Need help- Lines plan of steel fishing vessel

Displacement first as it is the primary requirement. Follow MARIN guidelines first then W&G as it has a wider range. L&B seems to be on the lower side.

 

You did not give draught.

Do not look for the Cb in the internet as you will not find it. It is in the formula. Displacement= L*Bwl*T (draught)*Cb

 

Almost all first world fishing fleets are length and tonnage limited. As such you will find that 30m and up vessels account for a small amount of commercial fishing boats. With the exception of surface long lining most vessels will be fairly significantly altered based off the dominant gear to be used. That design parameter matters most. A 30m surface long line boat will be radically different than say a 30m crab boat, even more so of a 30m trawler.

To get a rough estimation of designs look up

Hockema and Whalen (us)
Jensen marine (us)
Macduff ship design (uk)

I don't remember how many architects we called about 10 years ago trying to get help with a boat project. Most could wrap their heads around making a boat thats a bad idea, and trying to make it "least worst". Some of the most profitable boats are short, fat, and heavy. While inefficient on fuel they save on regulatory issues.

 

Check out FAO: http://www.fao.org/3/a-ak803e.pdf , it is 15 m or 21 m, not 33 m.

 

@AlanX, do you really believe that with the criteria of 40 years ago and the information of a 24 m vessel, a modern 33 m fishing vessel can be projected? The first thing you should ask the OP, among many other things and before giving pointless advice, is what type of fishing the boat is going to be used for because hull shapes can vary a lot depending on that variable.

@johncarlo, could you expand on your ship's SOR so we can say something useful to you? . (Ask your tutor, if you think it is necessary, because the data you manage are not enough)

 

Hello TANSL, principally I agree with your critics, but for studying purposes it is just as relevant to check the SOR of earlier vessels, and then find out how these requirements were achieved with the available technology at that time. Over the years I have seen students uncritically following trends "à la mode", ending up with crap, just because they have not understood the historic background of a specific design and the logic that should be applied for other/later conditions.

That's why I suggested the FAO book for a student, because it covers a number of fishing methods and gives examples of the equipment and working arrangements at the time; it is my way of indicating to the op that there are other factors than simple speed or load or Cb that count, in particular for a fishing vessel.

 

@baeckmo, I also quite agree with you and my "criticisms" were not aimed at your comments and advice at all. I just wanted to clarify, as I have already said, that the type of fishing totally determines the shapes of the boat and that, without forgetting what has been done up to now, gives the evolution that the technique, also in the procedures and in the mechanical means, has experienced a boat with ancient forms may be wholly unsuitable for today. And, furthermore, as can be easily understood, a tuna boat is nothing like a fishing boat for hook fishing, for example, or for purse seine fishing, for trawling or longlining, or with driftnets. ... The necessary machinery, the form of storage in holds or on deck, the space required on the work deck, the need for more pulling power or more speed, among several other things, totally condition the shapes of the ship. That's why I think the OP should give us more information.

 

Hello! My instructor did not give the Draught and cb of the vessel. She said that, search for cb of a fishing vessel and I will able to get the draught or depth of my vessel. Just displacement, LOA, and Breadth She gave to me and to my mates. And using maxsurf, I have to adjust my lines to meet the given displacement and Block coefficient that I found on an existing fishing vessel online.

Also, I'm already done with my scantling calculation using ABS rule book. I just have to finish my lines plan.

 

Your instructor is just testing you if you have a firm grasp of the ratios and coefficient. It is all inter related. This is just an exercise and L&B, MARIN, W&G tables are just to guide you. It is a design lane and guides you to the right path. There is enough room for you to wiggle and come up with something.

Question. Do you know what Froude number is? Without knowing this you would not understand an iota of the tables I posted.

Go back and study L&B. There is much more info there than I posted.

 

Noted, Sir. Thank you so much and keep safe always.

Thank you, everyone!

 

Comfisherman- This is just an student execise. It is the duty of the Lead NA to comply with/circumvent the statutory rules.

I know of the short, fat, very deep draught fishing vessel in Alaska since it was discussed here in the forum years ago. They have an unusual design because of the limitation on length.

Again, it is the duty of the senior NA to find/compromise with powering depending on the use of the boat. A trawler spend about 90% of its time dragging a heavy net in the seas. A long line fishing is again different.

 

Lines plan comes first. Scantlings is based on lines.