steel-ferro-cement sailboats

[ray13]

I found plans for a 35' sailboat, displacement 18,500 lbs. The plans for the sailboat are in ferro-cement. the plans in ferro-cement show the ballast to be 3.600 lbs. I want to build the sailboat in steel. Does anyone know if the weight of ferro-cement and steel are about the same or if ferro-cement is lighter? I have looked at different steel designs around 18,500 displacement and they show the ballast to be around 6,500lbs ( weight to ballast ratio 35%)
Should I just have the boat weighted? and is anything else considered ballast
Thank You

[Hank Rosendal]

If it was for me, I would have a naval architect to do the ballast re-calculations, as with too much ballast the boat would be incredible stiff, which results, amongst other things: the need to increase of size of rigging and scantlings and a lesser sea-kind motion.

Weight of steel hull depends on the material thickness used
-----------m2------SG--------thickness mm---weight kg
steel------50------7.4---------4----------------1540
steel------50------7.7---------5----------------1925
steel------50------7.7---------6.4--------------2464
ferro------50------2.8---------20---------------2800
ferro------50------2.8---------25---------------3500
ferro------50------2.8---------30---------------4200

These figures are without bulkheads, frames, stringers etc. Just some ball-park figures. Sorry for you guys who work in inches, feet and pounds. Some other forum readers might correct me on Specific Gravity for Ferro, concrete being 2.2 to 2.5

Have you consideredl ..... to buy an existing yacht. It would work out a lot cheaper, you can try before you buy, and the chance of a dream becoming a nightmare is greatly reduced.

[ray13]

Thanks for the reply. I can convert the mm & kg The Endurance 35 plans are no longer available.I just have the plans for the ferro-cement 35. I was told by one of the members that he Peter Ibold might be dead.
I've found four different adresses for Peter Ibold ? and have looked up builders of his design but they seem to be out of busness. I have the metal sizes from another set of plans (35' sailboat) to get the frames & plating size etc.
and I will contract a Naval Architect.
Thank You
Ray

[gonzo]

A ferrocement boat will have a round hull. To do the same shape in steel is quite difficult. Also, if you have a problem with ballast calculations, the scantling and structural redesign will prove too difficult. Go to St. Augustine and talk to Eric http://www.sponbergyachtdesign.com/. He is close to you and can do the engineering

[Crag Cay]

The Endurance 35/37, etc were a wine glass shaped, full keel design. This will be extremely difficult (expensive) to build in steel.

If you add the cost of this additional construction to the already high costs of any custom boat building and then add in the architect fees to have your plans redesigned for steel construction, you will find this is an extremely expensive way to get a boat.

The world is awash with perfectly serviceable second hand Endurance 35s. I don't think any of the GRP ones have come to grief in the last 39 years at the hands of the usual paranoid 'dangers' such as shipping containers or coral reefs, so why would you want to go to the ludicrous lengths of building one in steel?

I would suggest that if you want an Endurance 35, buy a good one on the used market and refit it. If you want to build a steel boat, buy a set of proven, steel boat plans. Don't mix the two.

[WestVanHan]

CC is 100% right.

A friend of mine bought a GRP oneof these last year for $50,000 in very nice shape,nothing needed.

Have you priced out a new driveline,sails,winches,genset, and mast?
It'll come to more than $55,000...

[ray13]

Thanks for all of your imput. I have cost out building a boat. I think your right.I should just get some plans that are designed for multi-chine steel.
then I would not waste two years building something that won't float.
Thanks again!