Author Topic: COLUMBINE - The Boat  (Read 23339 times)

Offline Robert Hornby

  • Full Member
  • ****
  • Posts: 394
  • Terrigal NSW Australia
Re: COLUMBINE - The Boat
« Reply #30 on: June 10, 2016, 06:21:10 AM »
Thanks Pete, but that doesn't sound like the name I used to remember- a much longer word I am thinking.
Robert
Age and treachery will always overcome youth and skill

Offline derekwarner_decoy

  • Full Member
  • ****
  • Posts: 424
  • Wollongong ...... Australia
Re: COLUMBINE - The Boat
« Reply #31 on: June 10, 2016, 06:52:27 AM »
Robert...

I have seen a few small images of the vessel lines you have created, however am unsure if the vessel beam...example Q>Q<Q is an actual simple dimensional flat deck beam/width or does it represent the narrower actual deck level beam due to the fore & aft rise of deck?

Derek
Derek Warner - Honorary Secretary [Retired]
Illawarra Live Steamers Co-op - Australia
www.ils.org.au

Offline Maryak

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1812
  • Aldinga Beach South Australia
Re: COLUMBINE - The Boat
« Reply #32 on: June 10, 2016, 09:01:15 AM »
Hi Robert,

Wonderful project!

I understand your foam idea on which will be overlayed the fibreglass. I am intrigued how you will ensure uniformity port v starboard carving/shaping from a single block

Maybe this could be more easily achieved by dividing the hull into waterline sections keyed to the keel viz:







Anyway food for thought maybe and I hope it helps just a little. Of course in your case there is no requirement to worry about the inner shape of each section as all the foam will dissapear when the glass work is complete and cured.

Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline michaelr

  • Full Member
  • ****
  • Posts: 103
Re: COLUMBINE - The Boat
« Reply #33 on: June 10, 2016, 09:10:15 AM »
There is a name for a smooth hull but it escapes at the moment.  :ShakeHead:
Robert

Fair

Pete
Smooth planked boat hull, Carvel
Mike.

Offline 10KPete

  • Full Member
  • ****
  • Posts: 1413
  • Nordland, WA, USA
Re: COLUMBINE - The Boat
« Reply #34 on: June 10, 2016, 09:31:39 AM »
Oh, I thought Robert meant a hull with smooth lines. As in a fair hull.....

Yes, carvel planking gives a smooth hull as opposed to clinker or lapstrake....

Thank you Michaeir!!!

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Robert Hornby

  • Full Member
  • ****
  • Posts: 394
  • Terrigal NSW Australia
Re: COLUMBINE - The Boat
« Reply #35 on: June 12, 2016, 07:50:35 AM »
Thanks Derek, Pete Bob and Mike,
Regarding the hull profile I have drawn up a profile for each 50mm division/spacing. I will print out each profile (from B to U)full size and then cut out a cardboard template which I will use to obtain the correct shape in the foam.











The profiles are just my thinking of how the shape should be, I only have photos of the prototype in the water so cannot see the lower portion. I have looked at other similar type boats on the net and used them as a guide. I am open to advice and suggestions.

Robert
Age and treachery will always overcome youth and skill

Offline 10KPete

  • Full Member
  • ****
  • Posts: 1413
  • Nordland, WA, USA
Re: COLUMBINE - The Boat
« Reply #36 on: June 12, 2016, 09:55:21 AM »
Too late now, but the last time I made a plug mold I cut out all those stations and laminated them into the foam block. Then just cut the foam down to the stations! WaaaLaaa!

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline MJM

  • Jr. member
  • **
  • Posts: 1
Re: COLUMBINE - The Boat
« Reply #37 on: June 12, 2016, 11:03:15 AM »
Can't help thinking that the profiles should be fuller in the middle, say between stations H to O. Some illustrations here may help
http://www.selway-fisher.com/Steam2030.htm

Martin
Martin

Offline Ramon

  • Full Member
  • ****
  • Posts: 1599
  • Suffolk in the UK
Re: COLUMBINE - The Boat
« Reply #38 on: June 12, 2016, 11:55:34 AM »
Hi Robert,

Looking at your profiles and layout I believe that what Derek was alluding to (post #31) is going to cause you some dimensional issues.

You have a deck plan laid out giving your dimensions across the beam at each station but the deck plan is flat and the same length as the transom to stem in the side elevation whereas it should be projected to take account of the sheer. As drawn your beam dimensions will be totally different at deck level given the curvature at each station.

I also agree with Martin (MJM) in that the profiles should be much fuller particularly in the centre area of the hull. I assume you have laid these out to take account of your steam plant volume/footprint.

Personally I would focus more on getting the shape fair and full to your eye than try to bring the foam to your templates -  as someone who began (working!) life on a shipyard there was an old saying - "N'e'er were a boat built with two sides a like"  ;)  You will be surprised just how close you will get by eye and if you felt that unsure it would be much better to shape one side and take a template from at each station and bring the other too it than to work to your templates which as you state are just your thinking of what they should look like.

If you want to be really certain how your hull form will look before attacking that foam block. Cut all your templates from thick card adding on the height from deck level (the sheer) to a straight horizontal line above (as you have drawn). Stick them to a board on a centreline and then run some thin strip wood around to see how they fair.

Pete has the right idea though - foam sections between card profiles. Shape the foam to just expose the card. But the profiles do need to be right and fair to begin with.

You did ask - hope that helps  :)

regards - Ramon


PS I have just had a quick google - there's quite a bit out there particularly on model yacht hulls but this might be worth a look as a starting point
https://www.youtube.com/watch?v=ocwKII_fVwU
« Last Edit: June 12, 2016, 12:09:45 PM by Ramon »
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Robert Hornby

  • Full Member
  • ****
  • Posts: 394
  • Terrigal NSW Australia
Re: COLUMBINE - The Boat
« Reply #39 on: June 13, 2016, 12:03:01 AM »
Once again many thanks for the input gentlemen, I do appreciate the time and effort put into the comments and valued advice. I do see that the form needs to be fuller and will redraw with this in mind. It will also give the advantage of a lower floor line around the steam plant.

The height of the bow some times looks quite high to me, I have a full side view of the prototype and from this scaled the deck shape.



As the prototype was built for the Admiralty around 1890 I am assuming it was used for transporting naval officers from shore to ship when anchored off. The seas can be quite lumpy off shore around Plymouth / Portsmouth so a high prow would seem to be a sensible design to limit the egress of water.

Another feature I am unsure off is the need to have a rudder support at its low point, i.e. an extension of the keel. I am presuming this would both provide support for the rudder and also some protection from hitting obstacles on the sea bottom.

Robert 
Age and treachery will always overcome youth and skill

Offline 10KPete

  • Full Member
  • ****
  • Posts: 1413
  • Nordland, WA, USA
Re: COLUMBINE - The Boat
« Reply #40 on: June 13, 2016, 01:51:26 AM »
The section templates are good if you are pretty set on that shape. Otherwise just start carving that big block, a little at a time, and the shape you want will appear. Just remember that the foam is expendable and if you take off too much just glue in another piece!

Let your inner sculptor out!!!

I've always felt that a boat that size and weight should have a rudder shoe. A good solid extension of the keel shoe.

I like the shear line on that boat in the picture. The trick with a high shear like that is to avoid a line that has a hog of any size forward. Sometimes a hogged line can appear from certain angles even though you don't see it in profile or plan.

Build that boat!!

Pete

PS: I was just comparing the shear you have drawn vs. the photo. I think your drawing has a shear just a tad deeper than the photo...????
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Maryak

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1812
  • Aldinga Beach South Australia
Re: COLUMBINE - The Boat
« Reply #41 on: June 13, 2016, 04:22:09 AM »
Hi Robert,

I hope this will help. The concerns others have raised about the excessive sheer in your model appear to be valid. What may have happened is that no allowance has been made for the camber of the hull/ deck athwartship viz:






Sorry for the quick and dirty hull but I was only interested in illustrating camber from your side on photo.

Regards
Bob
« Last Edit: June 13, 2016, 04:25:36 AM by Maryak »
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline Robert Hornby

  • Full Member
  • ****
  • Posts: 394
  • Terrigal NSW Australia
Re: COLUMBINE - The Boat
« Reply #42 on: June 13, 2016, 05:38:24 AM »
OK I have redrawn the profiles with more fullness, especially midships. Maybe I have gone a bit too far, I value comments here.

I still cannot get my head around the concerns regarding the deck line sheer. The board I made is of course flat but it represents the plan view of the true deck line as seen from above. I understand the curved length of the deck line will be greater but do not see how that will be a problem for me. I propose to form the foam to the profiles as drawn up to the deck line. The beam width at the true deck line is 290mm. The fibre glass will be applied to just above that (say 10mm) and when the foam is all removed the glass will be trimmed to the correct deck line. Also considering I am only getting the shape as reasonably close to the photos and hopefully not subject to scrutinisation by the British Navy.



Robert
Age and treachery will always overcome youth and skill

Offline Maryak

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1812
  • Aldinga Beach South Australia
Re: COLUMBINE - The Boat
« Reply #43 on: June 13, 2016, 08:14:26 AM »
Hi Robert,

I understand where you are coming from but for later on the transom at least should have a curved top or there will be an ugly gap and needless to say the reverse mold for the deck will have to be curved. Because sheer and beam are different at each station, the curves are therefore also different and not a constant.

One of the hardest thing about wooden vessel hulls is to visualise the 3D hull in a 2D lines plan. With most 19th century vessels every curve is either a spline or a bezier and there are vitually no straight lines vertically either side of midships.

Here is a fantail 19th century launch if you look closely you will see no vertical sides with a very slight Tumblehome around the midships sections. Tumblehome meaning the hull slopes outwards from the deck line before reversing to curve inwards to the keel.



HTH

Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline michaelr

  • Full Member
  • ****
  • Posts: 103
Re: COLUMBINE - The Boat
« Reply #44 on: June 13, 2016, 08:22:20 AM »
Robert.
It may be to late but you should have a look at the Bread and Butter method for building your hull mould, this link will give you the idea

http://www.sfmbc.net/Beginners_Boat_Building_Part1_R1.pdf

All the best with your project.

Mike.