Hercules by vaddoc - 1:64 - Steam Tugboat

[vaddoc]

Dear all

 

The Launch is not far off completion so I have been thinking what might be the next project. I really wanted to embark on a long journey, 10 years or more, and built something with many masts and frames etc. Certain funding issues though came about so this journey will have to wait.

 

That same day though I came across a lovely boat in the gallery by @Kevin. I 've always liked Tug boats and looking at this wonderful model I was immediately sold. I would build Hercules!

 

Now, there of course the kit by Occre but I should be able to scratch build it, shamelessly guided by the images on their website. This would be my first POB boat.

 

But of course, some lines would be necessary so off to the internet to get any boat lines that would be close enough. To my surprise, google returned a wealth of information - a specific site https://www.themodelshipwright.com/high-resolution-ship-plans/cargo-ships/steam-tug-hercules/ was of great help.

 

This site had everything - offsets, info, photos and lines. Apparently the boat was in dry dock for repairs and they took the opportunity to lift some lines. 

Indeed a wealth of info but of course serious lofting would be needed. First thing to do was to get everything onto CAD (I am hopeless in drawing with a pencil) and see whether I could get a hull out of this ocean of numbers.

 

So a brief hibernation period for the Launch to get this project under way. I am not sure how it will work, what scale or the level of detail but we ll figure it out along the way, at my usual snail pace.

 

I hope you ll join me on this new journey and thank you for visiting.

 

Best wishes

Vaddoc

[vaddoc]

Ok, so I have been playing a bit with the lines on CAD and first impression is that this is not going to be straight forward.

 

First we need to define the sheer. This is the first line according to the table of offsets:

It looks fair but it is not. With a bit of attention, we get a fair line

Same for the second view

And combining the two we get a sheer (not THE sheer - this will come later)

We can create a bit of surface, just for fun

Now, this is incomplete as the stern is missing, it does not reach the stem and is not clear how wide the keel is but it is a start.

 

Then, we get the waterlines and buttocks - All needed a bit of work to become fair

Combining everything we get an idea of the hull. This is not the actual hull - A lot more work will be needed to get there. I also added the keel which is not given in the offsets.

Next I actually used the plans to draw the frames and all other lines by putting the image sized appropriately as background and drawing lines on top. I combined all and this is what came out

It actually seems pretty close, it even gave a smooth hull. But it is not ready yet.

After a lot of work, the hull and lines were getting tighter but far from true. A lot of eyeballing was used, moving lines were it seemed they wanted to be.

Now that I had an idea of the shape, it was time to start again. I first faired the diagonals which I had not used at all so far. Then I rearranged the buttocks to reach the keel where they were supposed to. Finally, I tweaked all these lines to make sure they were fair and interacted at all intersections. This took a lot of work.

But when I added a couple of waterlines, these diagonals and buttocks had to be adjusted again to interact with the waterlines and with each other.

Only the upper waterline is completed. There are 7 more and incorporating these into the hull will certainly need revisiting every other line. There are also a few areas in the hull that are of concern, the first frame near the bow where so far the hull is taking a bit of an acute turn, the cut out for the propeller, the curve at the bow but these bridges will be crossed at a later time.

 

This is all I ve managed to do but so far it looks promising.

 

Till next time

 

Vaddoc

 

[Dr PR]

Vaddoc,

 

I have generated 3D drawings of several hulls from the numbers in the Table of Offsets. As you said, it is a lot of work!

 

I found several errors in the offsets for each of the hulls. They were usually off by 1 foot, 1 inch or 1/8 inch - the units used in the tables. First an engineer created the offsets, probably using a slide rule or maybe a mechanical "adding machine" for some of the older hulls - the first chance for error. Then the engineer had to write all of those numbers down - the second chance. Then the draftsman had to read the engineer's hand writing (a third chance for errors) and copy all those numbers onto the drawing - the fourth chance for error. And, of course, I had to copy them all into the computer. Five chances for error. It is a wonder that any of it came out right!

 

And then, after finding and correcting these simple numeric typo mistakes, I found that the station/frames generated from the data didn't fair smoothly after all. Like you I spent a lot of time tweaking the lines to get a smooth hull. But even so, I am sure the hull dimensions are more accurate than if I had just traced lines from the hull lines drawings.

 

Your hull is looking good!

[KeithAug]

20 hours ago, vaddoc said:

so off to the internet

I had a look at the site - excellent information - even the plating drawing.

 

Marvellous CAD work - I wish I understood it all. Maybe I am glad that my draughting training was completed at the turn of the Stone Age.

[FriedClams]

Hello Vaddoc and congratulations on starting a new project.  This is a vessel I once considered scratching myself, so I will certainly be following your progress with interest.

 

The Hercules is a great choice and as you probably know, she is a US National Landmark and part of the San Francisco National Maritime Historical Park.  Consequently, much is known about her.  The vessel is part of HAER (Historic American Engineering Record) National Park Service.  The drawings you have are public domain and the originals are available for download at various resolutions from the Library of Congress website.  Also available at the site are photos, photo caption document, and a data document containing interesting stats and brief history.  

 

Steam Tug HERCULES, Hyde Street Pier, San Francisco, San Francisco County, CA (loc.gov)

 

San Francisco Maritime National Historical Park (U.S. National Park Service) (nps.gov)

 

The historic park also has a research center that may be of help to you.

 

Maritime Research Center - San Francisco Maritime National Historical Park (U.S. National Park Service) (nps.gov)

 

Best of luck on your new project.

 

Gary

 

[bricklayer]

Hello Vaddoc,

what degree and what number of control points did you chose for the lines? Do the station lines have a higher point count and higher degree than the longitudinal lines

(buttocks, waterlines and diagonals)?

According to my experience a low degree and a low number of points results in the smoothest curves. But the deviation from the points given by the table of offsets is highest.

If the number of control points equals degree of curve +1 then the curve doesn`t have any abrupt changes in curvature, thus the curvature graph is smooth.

What`s your approach? Do you start with a high number of control point and rebuild the curves with less points if applicable or do you start with few control points and rebuild 

with more points if necessary?

Either curves are fair or congruent with the curves of the lines plan or points of the table of offsets. We can`t have it all. So we have to compromise.

I don`t envy you in re-engineering a ship`s hull.

 

Michael 

 

[bricklayer]

Hi Vaddoc,

one more question. I`m sorry to bother you.

Which version of Rhino 3d do you use?

I ended upgrading Rhino at version 5.

I don`t think that I need something more sophisticated

[Bedford]

Chair pulled up, coffee brewing. I'm in for the whole show and looking forward to it

[vaddoc]

Dear friends

 

Please accept my apologies for the huge delay in revisiting the log and replying to your comments - you all know how it gets...

Although I did not find time to visit the log, I did do some work on the boat. So here it goes.

 

@Dr PR Phil you are absolutely right. I could not make the numbers in the table of offsets work and in the end, I gave up. More on this bellow.

@KeithAug It can certainly be done with a pencil and ruler and actually it is easier to get fair curves with a batten. However, despite having a professional draftsman (woman) for a mother, I cannot draw - I need a computer to help me draw a straight line!

@FriedClams Many thanks Gary, I was not aware of the links!

@Bedford Excellent, as always a pleasure!

@bricklayer Michael, any version is fine. It is actually not too complex - Analysing the curve shows its fairness. If it is not fair, use the fair command. A bit of eyeballing and a bit of manually adjustment of the curves is needed. I use many check points to start with, when the curves are all over the place and as the get closer and fairer, I use less so that the curves get fairer but without allowing the curves to wonder too much off the originals. The lines do need to interconnect when going through a lofting cycle - they do no longer connect after the lofting cycle finishes and the lines are corrected and faired but this is ok. With every lofting cycle the lines get closer but in the end, it does not need to be perfect, just close enough - the wood will correct the rest.

 

So, I initially used the table of offsets - These were apparently taken directly from the boat when it was in drydock. I started over a number of times as I could not really make things work. Finally I decided to give up on this table. Something did not add up - the keel, the numbers - something.

 

However, there is also this:

This is the half model of the boat and lines were taken of it

 

So I decided to use these line, tracing over and importing into CAD. 

Immediately it felt better. A couple frames at the bow were wrong and the stern needed a bit of work but overall, these lines appear better and closer to the actual boat. So after a few cycles I ended up with a reasonably fair surface and frames that are reasonably fair and pretty close to the original tracings.

I think it is ready to move on further - I hope that tolerances will be corrected with a bit of shimming, bit of filler, bit of sanding.

 

So, next I made the deck which unrolled gives us the shape of the plywood - I though about adding camber to the deck but I think it will be fine without.

 

Now, I ve never built a POB boat before and for this project of course I had a look at the Occre model to get some ideas. Now, Hercules is 151 feet long and the Occre model at 1/50 scale makes a pretty huge model 920mm long. I think I ll go with 1/64 which will produce a more manageable 718mm model.

 

Till next time

Vaddoc

[vaddoc]

Dear all

 

I just spent a small fortune in plywood, so should not be long before some wood dust is made - so time for another update.

I also have been unable to work due to creaking bones so an opportunity to do a bit more work on Hercules.

 

So I ve been thinking how to arrange the keel and frames and what material to use. As I always do I will laminate my own plywood to make sure it is strong and dead flat. Also, I will use plywood for planking - Hercules hull was made from steel sheets welded and riveted together without much care for aesthetics so planking the model in the usual way is not appropriate, I will use sheet material without being pedantic about fairing - the seams probably need to be quite visible. I decided to use 1.5 mm ply - quite an overkill but it will be a big model and I think it needs this thickness to be stable and for the fasteners to hold well.

 

The hull will be 3.9 mm thick, laminated from 2 pieces of ply 1.5 mm each, 0,9 mm should be the thickened epoxy layer. I will measure it though and if it is less, I will adjust the lines

The frames will be very wide, 5.8 mm, laminated from 2mm and 3 mm ply - again, if the new ply has different dimensions I will readjust the frames (which will be a big job)

 

So a few photos

 

The hull is finished! I suspect there will be some pretty large tolerances and gaps but I hope that as I will not be cutting the wood accurately, one mistake will correct the other - of course may make it worse but lets be optimistic.

 

The stern was tricky to get as there is no transom. In the original design there were many metal beams spreading out at the stern to give the correct shape to the sheer which aft is a vertical wide zone. There will be a lot of pressure at this point to convince the ply to take the turn so I overbuilt the area. There will also be more reinforcing pieces of wood connecting the frames inserted during construction.

The frames are offset to accommodate the hull thickness of 1.5 mm. This is a wonderful feature of CAD - press a button and a complex surface is offset to whatever thickness within 2-3 sec!

The frames should fit a 900 x 300 mm piece of ply

The keel is a bit complex and pretty large at 720 mm

The deck will also be 1.5 mm to hold fasteners well - I did not account for this thickness but I think it will not make any difference.

 

I will start work on the superstructure after I will have laminated the ply, so I will have accurate dimensions of the actual hull.

 

Till next time

Vaddoc

[bricklayer]

Hi Vaddoc,

did you modify the original design of the tug by adding three centerboards?

 

Or is it daggerboards?

Edited 11 hours ago by bricklayer

[vaddoc]

3 hours ago, bricklayer said:

Or is it daggerboards?

These are just little feet to help keep the keel horizontal!

They will be cut off in the end.

Edited 8 hours ago by vaddoc