strongback for 57' steel hull

[Enders]

Anyone know where is a good description I can find for building a strongback for a 57 foot steel hull? I'm told to use 6"x2" timbers or I-Beams, but not real sure how they should stand properly. I will build upside-down, and seems like using either material, I will have to use several together and must be straight. Just looking for details. Thanks.

[MikeJohns]

I would build a flat bed frame from I beams and set up the frames on this welding temp headstocks to each frame that are in turn welded to the bed. The bed should be a crude boat shape parallel in the middle tapering at the ends. The Central keel is added early and holds the frames in position Then you only need to brace the keel.

Steel is better to use than wood as you can tack to it easily. Steel from a scrap yard is the way to build the bed.

Your designer should give some hints on how to go about the job, who was he?

Cheers

[Wynand N]

Timbers
No, use a steel only construction for your strongback since you gonna build a steel hull.
I used 76 x 152mm (3 x 6") tapered lip RSJ iron for the complete construction of strongback. It is sturdy and easy to weld the frames headstock's to the strongback.
If you go to the following link, there is a photo of a 57ft hull in the process of being turned over which clearly shows the strongback and the framing attached to it. Tip, make sure the strongback is absolutely level and secured - I used a dumpy level to set it up and then rawlbolted to floor.
http://boatdesign.net/forums/showthr...936#post111936

[larper]

Hi. im building a 60ft'er. Here is a picture of my strongback at a very early stage with only frames erected.

http://krabaten.no-ip.com/nova/4857913/index.html

-- Per Larsson / sweden

[Tzuriel]

Hi Larper,

I was going through and studying your pictures, and I have to say, I was concerned with the way you started doing the radius sections as compared to the methods I've been reading, but you pulled it through nicely. You have some good photos and I've learned a bit from them.

I have a few questions for you. It looks like you've been working on this for not quite 2 years now? How much time p/ day, days p/ week have you been spending on it?

From the pictures, I was guessing that was a 49-53 footer.

[larper]

Hi Tzuriel

Im glad im able to help with photos

Im working on the boat saterdays and sundays and a few extra dayts in between. last summer i had 5 weeks summer wacation and this summer i had 4 weeks. that summs up to something like 4 months fulltime work. My wife is a great help so that makes it doubble, almost. she needs some guideance from time to time .

The only cutting tool were using is a 7" and a 5" grinder and alot of disks!!¨

The boat is 61 loa, beam 16feet