aluminium and composites planing hulls and fast attack crafts

[ankitnehra1990]

I am working on planing hulls and fast attack crafts.
while on the project i have focussed my work on building these with either of aluminium or composites in lieu of their advantages.
So, I want to make a size range that would specify the range in which hull can be made of aluminium or composites.
Request assistance from all members to throw some light on the topic.

 

[daiquiri]

Can't say that I am particularly eager to help unknown people to make a fast attack craft.

Can you tell a bit more about the scope of your project?

 

[gonzo]

What are your qualifications? It seems strange that a Naval Architect or engineer would go on a forum to ask basic questions.

 

[TANSL]

The question is not basic at all. The "range in which the hull can be made of aluminum or composites" depends, among other things, on the type and power of projectiles that can receive the hull.
Like any other type of boat, when you set the SOR you can analyze what material is appropriate to do so.

 

[gonzo]

If he needs instructions on how to make an SOR it is really basic. It is not possible to give an answer to a generalization like that. What is fast? What is an attack vessel? What are the advantages you are considering? What are the upper and lower limits of the size range necessary? What armament are they carrying and where is it mounted? What kind of fuel will they use? What sea conditions will they operate in? Etc, etc.

 

[TANSL]

There is no reason to suppose that ankitnehra1990 not know how to do the SOR of their ships. I think the only thing that currently we can advise him is that to make the SOR and with it, we can answer more accurately.
One thing I think would have to say is that, perhaps, the composites are not the best material for landing crafts or for attack crafts. What do you think Gonzo, what experience you have on this?

 

[gonzo]

There are plenty of fast patrol boats in composite. We had one entered in the Cowes to MonteCarlo race to prove its performance. Unfortunately, the race fell through because of bad management. The police and Coast Guard use a lot of aluminum boats too. In the past many patrol boats were fiberglass. For example, the PBRs.

 

[Ad Hoc]

So, I want to make a size range that would specify the range in which hull can be made of aluminium or composites.

Not withstanding all the comments above.

You need to DESIGN your boat. Once you designed your boat in aluminium and then in composite YOU will see what the differences are between them and then be able to judge what the differences are in terms of weight and cost of production and materials.

It's that simple.

 

[gonzo]

Usually, agencies specify materials and methods of construction. Sometimes they have open bids where designers compete. That entails showing what advantages one design has over the rest. Composite vessels are reaching 200 feet, so that is about as large as a fast patrol boat gets.

 

[PAR]

Sounds like the fall semester is rapping up over there guys . . .

 

[TANSL]

There are many attack crafts hulls built of composites. Another thing different is in relation to the "landing crafts".
In any case, building composites attack crafts is not an easy task, must meet certain requirements, you need calculate scantlings for very heavy loads, impacts, and do many tests on materials along the construction. Structural fire protection in composites, is not easy, nor cheap.
ankitnehra1990 should take into account, in addition to the mechanical condition of the materials, ease of construction in each case. Of course, everything depends on the SOR for boats. I agree with the comments of PAR.

 

[gdavis]

hello ankit... check out Trefoil Marine. Front Street Shipyard is building fast patrol and attack power cats for Trefoil Marine. These boats kick butt, I know because I had a ride in one as did all the craftsmen who worked on them. I've been installing seats,consoles,bumper collars,etc,etc. Last week I built a plug for a redesigned console. The hulls and lower bridge deck are layed up in one piece then the work deck with raised sides is attached at molded in flanges. The joint is hidden by the bumper collar. There is talk about some Kevlar going into the outsides of the hulls and raised sides.The first one was powered by twin 300hp outboards,it missed the mark on the projected speed by one mph. It did 49 instead of 50! Close enough. Being cats they are very stable and smooth riding even in some unsettled seas. They also don't seem to be affected by added weight such as extra crew and gear. We also got news that we will be building a 80' and the mold has been ordered. This too will be built with composites and will be infused as are the 30's. We don't however get to install the 50 cals and go out and test them! Shucks! So take a look at them, see what ya think, might be some helpful info. The owner of Trefoil Marine is a great guy to work with, maybe you guys could yak a bit.Whats up with some of these rude members. Maybe they need a happy meal or something...........................................later....g

 

[gonzo]

MILSPEC is a good place to start. The specifications are conservative and have easily found background and track record.

 

[Mr Efficiency]

I read the opening post three times and no idea what the question is, let alone the answers !

 

[PAR]

I read the opening post three times and no idea what the question is, let alone the answers !

I'm sure his instructor has a similar issue with him . . .