Help Finding Lines Plans

[ldigas]

Originally Posted by EngineerGirl

I know! I'm a little irritated because, although I am a design engineer, this is the first class on naval architecture (or really any architecture) that I've taken. The only class I have had that remotely covers these subjects is statics. Furthermore, this is only the 4th class, and during the previous classes, we just went through slide shows of old navy ships (snore, snore).
I think I found the perfect hull, however:
http://www.dhylanboats.com/grayling_plans.html

What a beautiful craft!

Ugh, I would've recommended maybe something simpler for a start ... you're gonna have a hard time modelling that keel, if you don't know what you're doing in advance. Depending on whether you'll be doing hydrostatics by hand (Excel), or in some software - most softwares have, well I won't say problems, but you have to model the hull in a way "that fits them". Keel is a knuckle point.
Even though for actual hydrostatics results this probably won't make a difference, it could give you a bit of a headache :/

[ldigas]

Originally Posted by EngineerGirl

I know! I'm a little irritated because, although I am a design engineer, this is the first class on naval architecture (or really any architecture) that I've taken. The only class I have had that remotely covers these subjects is statics. Furthermore, this is only the 4th class, and during the previous classes, we just went through slide shows of old navy ships (snore, snore).
I think I found the perfect hull, however:
http://www.dhylanboats.com/grayling_plans.html

What a beautiful craft!

What exactly is "a design engineer"?

The college curiculla probably differs from my part of the world, but in here we have studies of nav. arch, architecture (regular architecture), mechanical engineering (weapons), civil engineering (targets) and industrial engineering ... along with a few more ...

Industrial engineers (they're commonly called "design enginners" in here) design things like iPads and so on ... but they have nothing to do with naval architecture.

Therefore my confusion ...

[upchurchmr]

EngineerGirl,

There is one helpful book on boats that has recently been offered free at this link: http://www.westsystem.com/ss/assets/...k%20061205.pdf
"The Gougeon Brothers on Boat Construction" which has a beginning section which might help. This may not the the classic definitive book but I really like it. There is way too much knowledge on boats to fit in one book.

You might just contact the person trying to sell plans for your Sardine Boat and ask what the station spacing is, and where the station 0 is located from the bow. Students can get away with asking for a lot if they are just nice and sound like they know something. Study up a little before asking.

Petros's comments are worth thinking about. Most of the Bachelor's degree courses are relatively simplistic and not much is expected, but accepting that leads you to not getting much value. Generally if you know the terms (definitions) of a given field and can put together a simple question you will impress people. I got my first and only engineering job that way. To keep it required much more, but what would you expect.

Enjoy your college time, it is generally the easiest time to get a lot of information, just not as indepth as you might want. Talk to the instructor and push for what you need. You will get more than you might expect. Good luck.

Idigas,

I work in military aerospace and design engineer means someone with a engineering degree who is actually designing parts for the aircraft. Those who are actually designing the aircraft as a whole get called Configuration Designers. All of these people run the extremes from nothing more than draftsmen (no degree, no imagination) to the equivalent of Aerospace scientists - depending on their personnel skills. I think there is no one definition.

[DavidJ]

Engineergirl most of the information you require is listed on the webpage for the plans you like. I've doodled on the attached profile view.

The profile view is the view of the boat looking at it directly from the side. Stations are transverse slices through the boat. The body plan shows these slices on one view. Normally the right side shows the forward stations and the left side shows the aft stations.

It isn’t usual for people to refer to the reference length or reference beam. What your instructor means is show the length and beam the designer uses for reference. For example some designers use the overall length and others use the waterline length. The instructor says this same thing when he says to establish the reference beam as max beam or BWL (beam on the waterline). What did the designer consider most important?

DWL = design waterline or designated waterline. This usually means the same thing as LWL = load waterline or length on waterline

The reason your instructor has grouped reference length and station spacing together is because in a traditional lines plan if you have one you can figure out the other. Normally a lines plan has 10 evenly spaced stations spread along the DWL. The first station is number 0 (in this case) and it is located at the intersection between the DWL and the forward extreme of the vessel. This is called the forward perpendicular (FP). The last station is located at the intersection of the DWL and the aft extreme of the vessel. It is number 10. It is sometimes called the aft perpendicular (AP) although not always. Naturally station 5 is located at the midpoint of the waterline. This is called midship and it is designated by the circle with two arcs. The particulars list the LWL as 60’10” or 730 inches. Divide that by 10 and you get the station spacing of 73 inches. More stations can be added as the designer feels is necessary to properly represent the shape of the vessel. You can see that is this case the designer has added a half station between 0 and 1 and another between 9 and 10. I have highlighted the stations in red on the profile view so they are easier to see. The half stations are blue. I have also numbered the stations so you can see how they match the stations shown on the body plan.

[upchurchmr]

DavidJ,

Nice, are you a teacher?

[WhiteDwarf]

EngineerGirl,

The excellent English magazine Watercraft publishes a set of top designer Paul Gartside plans in each of it's editions. It is available on line at:

http://www.exacteditions.com/exact/browse/603/1075

and the free sample edition of the magazine provided includes a set of plans for an 18 foot workboat.

Gartside's web site is:

http://www.gartsideboats.com/

It might be useful to you...

[Angélique]

Originally Posted by WhiteDwarf

The excellent English magazine Watercraft publishes a set of top designer Paul Gartside plans in each of it's editions.

The ones I've seen were printed so small on a few A4 magazine pages that I couldn't read much, you could buy the plans for regular prices if you wanted them larger . . . .

The free sample edition is recommended though, it's a nice magazine - - - - - except the small printed plans if you want use them

Good luck !
Angel

[Angélique]

Here is how it looks . . . . page 16 till 21 of the Free trial issue.

Advantage of on screen is that you can enlarge the view

Good luck !
Angel

[ldigas]

Originally Posted by DavidJ

Engineergirl most of the information you require is listed on the webpage for the plans you like. I've doodled on the attached profile view.

The profile view is the view of the boat looking at it directly from the side. Stations are transverse slices through the boat. The body plan shows these slices on one view. Normally the right side shows the forward stations and the left side shows the aft stations.

It isn’t usual for people to refer to the reference length or reference beam. What your instructor means is show the length and beam the designer uses for reference. For example some designers use the overall length and others use the waterline length. The instructor says this same thing when he says to establish the reference beam as max beam or BWL (beam on the waterline). What did the designer consider most important?

DWL = design waterline or designated waterline. This usually means the same thing as LWL = load waterline or length on waterline

The reason your instructor has grouped reference length and station spacing together is because in a traditional lines plan if you have one you can figure out the other. Normally a lines plan has 10 evenly spaced stations spread along the DWL. The first station is number 0 (in this case) and it is located at the intersection between the DWL and the forward extreme of the vessel. This is called the forward perpendicular (FP). The last station is located at the intersection of the DWL and the aft extreme of the vessel. It is number 10. It is sometimes called the aft perpendicular (AP) although not always. Naturally station 5 is located at the midpoint of the waterline. This is called midship and it is designated by the circle with two arcs. The particulars list the LWL as 60’10” or 730 inches. Divide that by 10 and you get the station spacing of 73 inches. More stations can be added as the designer feels is necessary to properly represent the shape of the vessel. You can see that is this case the designer has added a half station between 0 and 1 and another between 9 and 10. I have highlighted the stations in red on the profile view so they are easier to see. The half stations are blue. I have also numbered the stations so you can see how they match the stations shown on the body plan.

Interesting ...

in every document I've had in my hands so far, the station 0 has always been at the stern, not the bow.

And, aft perpendicular has always been defined as the intersection of the rudder axis with the stern conture, rather than the dwl/conture curve.

The forward perpendicular, was, as you said, dwl/front conture curve.

[DCockey]

Originally Posted by ldigas

Interesting ...

in every document I've had in my hands so far, the station 0 has always been at the stern, not the bow.

The majority of small craft plans from North America I've seen have the first station at the bow.

And, aft perpendicular has always been defined as the intersection of the rudder axis with the stern conture, rather than the dwl/conture curve.

The forward perpendicular, was, as you said, dwl/front conture curve.

Conventional practice for ships, as defined in the ITTC Alphabet Dictionary, has the aft perpendicular at the stern post for vessels with sternposts, and through the centerline of the rudder stock for vessels without sternposts. Letcher, in The Geometry of Ships which is a volume in the revised Principals of Naval Architecture series, states that for military vessels the aft end of the design waterline is frequently used for the aft perpendicular.

Forward perpendicular is given in the ITTC Alphabet Dictionary as the intersect of the fore side stem with the load waterline.

For small craft there is not a consistent standard for fore and aft perpendiculars, at least in the plans I've looked at. In fact on many plans FP and AP are not defined as such.

[DavidJ]

Yes I did say the AP was not always at the intersection of the DWL and the stern. The rudder stock is indeed a common location for the AP. I thought about putting that in my first post but I thought it might cloud the issue with an unnecessary fact.

As to where to locate station 0, again this is a matter of custom or standards being used. It is customary in the UK to place station 0 aft and in the USA it is more common to put it forward. Some, but not all, double ended ferries (which are have identical fore and aft ends) will place 0 at midship. And all this can go out the window when you are comparing big ships and small craft or navy vessels and commercial vessels as they will all have their own standards.

These discrepancies are why it is important to establish what the designer used as reference. Remember, reference length, reference beam? What was his or her reference?

One more point. Don't confuse stations with frames. Station number and station spacing are really only meaningful on a lines place. They have absolutely nothing to do with frame number or frame spacing.