Structual options 3

[boatboy]

I'm designing a 50 foot sports cruiser & I'm getting myself very confused on what the best material will be to build the hull from. Can anyone give me an idea on the advantages & disadvantages between CONCRETE,FIBREGLASS,WOOD & STEEL designs? And in regards to concrete boat structures, what composition mix is in this material?

 

[jayar]

With regard to your your query on material for construction I would like to suggest as follows:
-Being a sports cruiser vessel speed must be a prime factor. In this
regard fiber glass couldl be the best choice being lighter of the other
three materials in consideration, such as wood, ferro- cement and
steel. Also you could get a very good finish in FGlass. However, one
disavantage of Fglass will be that you may require a mould. But
there are ways to overcome this.
Advantage for steel and ferro-cement is that material readily available.
Steel as material is very familiar. Easy to work with. Steel and cement may
be compartively cost effective, but are heavier when compared toFGlass.
Wood could be quite expensive but may
be easy to work with.Also it is friendly to environment.
My best wishes for the project.

 

[Cyclefrog]

For a sport cruiser, either fiberglass or aluminum are the best materials. Stay FAR away from ferro-cement--it's definitely not suitable for anything that moves faster than displacement speeds.
One resource to check out before you start: Professional Boatbuilder (

http://www.proboat.com

) has lots of good technical material.
Also: I've been in the boat-building industry for 25 years now, with experience in just about every material known. My personal choice for a one-off would be sandwich construction using ATC Chemical's Core-Cell foam. We built a 50' sailboat hull for a customer a couple of years ago, and were very pleased with the results. We used biaxial knitted reinforcements and vinylester resin, and liked the results sufficiently that we are now using the same process to make the plugs for our new 55' x 17' long-range trawler yacht. After we pull the molds from the plugs we will then turn the plugs into a finished vessel.
Finally, if you're considering building multiple copies of the vessel for sale to others, look into having the tooling built by a CNC process by a sopecialist such as Janicki Machine.

 

[JohnboyFaye]

I would go with fiberglass sandwich. Wood rot may come back at you later and you need to know enough about wiring to prevent galvinic corrosion in the aluminum.

 

[arto]

If you make a mistake building a wooden boat, at least you can cling to the wreckage. ;-)

 

[boo1]

Cyclefrog what biaxial knitted reinforcements and vinylester resins did u use?

 

[Cyclefrog]

boo1 -- If I remember correctly, we used BTI CM3208 (32 ounces per sq yd of knitted roving on a 0/90 orientation with 3/4oz of mat bonded) for the first two layers against the core, and one layer of +/-45 2408 for the final (surface) layer. Resin was Reichold's Hydrex. We built a poly tent over the whole thing to make an oven for post cure. You can get a look at the resulting hull on page 21 of the March/April 2003 issue of "Boatbuilder" magazine.

Also, we launched the completed 57 x 17 "plug" last Thursday. The boat turned out beautiful.