Fitting out a new hull

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Anne from Little Britan
Anne from Little Britan
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Fitting out a new hull

Post by csonics » Wed Nov 18, 2009 7:33 pm

Posted on behalf of P.F.Cuthbert@Classicfm.ne

P.F.Cuthbert@Classicfm.ne
Steam on Deck


Joined: 24 Nov 2007
Posts: 52
Location: Cheshire, UK
Posted: Sun Nov 16, 2008 2:12 pm Post subject: Fiting out a new hull
Dear Steamboaters

I am now in the happy position of having a hull to fit out. However, before committing resources to the task I am planning it all on the drawing board.

The first query that has struck me, is what amount of camber to set for the fore and after decks. Does anybody know of a rule of thumb for a good looking camber, e.g. X inches per foot of beam?

I have looked at a number of photos of launches and some seem to have far too much, others too little and onlly a few seem to have it "just right".

I would welcome your observations.


Pete C.
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preaton
Just Starting Out


Joined: 19 Dec 2007
Posts: 10
Location: Auckland, New Zealand
Posted: Tue Nov 18, 2008 3:59 am Post subject:
Hi Pete,
I don't know that there are any hard and fast rules for the amount of deck crown - it is usually up to the designer. However here are some examples from plans I have. The first 4 are Paul Fisher designs, the 5th from Phil Bolger

50mm with beam of 1530
65mm with beam 1880
65mm with beam 1750 (my boat)
75 with beam 1600
2" in 6' (51mm in 1830)

I'm just doing the decks on my boat and they look about right. However "about right" must vary with beam to length ratio as I think short beamy hulls probably look better with a higher crown. Also the amount of sheer is important. The only way to judge is to make some full size mockups and your eye will soon tell you - easier than trying to do it on a drawing board.

Cheers
Paul
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P.F.Cuthbert@Classicfm.ne
Steam on Deck


Joined: 24 Nov 2007
Posts: 52
Location: Cheshire, UK
Posted: Tue Nov 18, 2008 4:36 pm Post subject:
Dear Paul

Thanks for your observations. I will get some scrap board and do a few trials as you suggest.

Best wishes


Pete
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farmerden
Warming the Engine


Joined: 19 Apr 2008
Posts: 70
Location: Shawnigan Lake,B.C.
Posted: Sun Nov 23, 2008 7:10 pm Post subject:
Hi Pete; Ever since I read your question I have been going down to feed the cows and check the decks of the "Steam Queen" . However after feeding the girls and having a stimulating conversation with them ( well OK a rather bovine conversation!) I forget to take the measurements! Well today I tied a string on my finger and remembered! At the stern just behind the cowling it measures a 3/4" fall from center .Total width at that point is 5 ft. So a fall of 3/4" in 2 1/2 ft. (19.05mm in 762mm) I'm still fighting metric so I hope the conversion is correct! It appears that Paul's measurements are nearly double mine. The bow is the same and the ol' girl definately sheds water (Somewhere in this forum is a picture of the "Steam Queen" so you can reference where I took the measurements.Looking at the boat I thought it appeared correct and was suprised that there was that much curve there. I think using mine for a low and Paul's for a high you can't go wrong! People like to sit back there on sunny days and don't seem to roll off!! But I think a game of marbles is out of the question!! Den
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P.F.Cuthbert@Classicfm.ne
Steam on Deck


Joined: 24 Nov 2007
Posts: 52
Location: Cheshire, UK
Posted: Thu Nov 27, 2008 4:50 pm Post subject:
Dear Den

Thanks for your post. I will add your dimensions to the list.

Don't worry about the Imperial/Metric issue. The UK is a mess as far as measurement is concerned. Builders here use sheet materials in 8 X 4 sheets, but sold with the metric dimensions expressed in millimeters! However, I have a solution. It is a most useful steel tape that has feet and inches, etc on one side and all the millimeter stuff on the other. Just mark it up and turnover the tape. Who needs to do conversion sums?

I have just been hunting for your photos and got distracted by the videos. What a fine vessel and the lake (?) looks wonderful. Just what is needed to stoke up the enthusiasm.

So, back to the boiler casing drawings as they are still not sorted!

Best wishes


Pete
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Froya66
Just Starting Out


Joined: 12 Oct 2008
Posts: 9
Location: Esbjerg, Denmark
Posted: Sat Nov 29, 2008 3:45 pm Post subject:
Hi Peter

When I made the decks on my small launch Frøya, I consulted the book “Building small boats” written by Greg Rössel.

The book suggests 2 inches of camber over 4 ft of beam.

I reduced this measure to 45 mm at max beam 1150 mm.

Afterwards I think that it could well have been made to the original suggestion

I know the season is not the right for field studies, but my suggestion is that you measure those you like, and do it correspondingly.

If you whish I will mail a few photos to show you what my decks look like

Best regards
Jørgen Hansen
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P.F.Cuthbert@Classicfm.ne
Steam on Deck


Joined: 24 Nov 2007
Posts: 52
Location: Cheshire, UK
Posted: Wed Dec 03, 2008 3:56 pm Post subject:
Dear Jorgen

Many thanks for adding to the data set and to the ideas. I like the idea of "field studies". I will see who I can arrange to visit that lives not too far from me.

Best wishes


Pete
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