60 feet steel sport fisher with enlcosed bridge

Dear Barry, in this case I think my perspective as European and my perspective as naval technician has made me think that Capt. Bahi surely had thought about many things before we came knowing everything.
I'm not shipbuilder but I know how ships are constructed and many shipyards have built their boats with my drawings. Capt. Bahi, imo, not need to have experience as a builder to know about shipbuilding. And some times, for many issues, having common sense is enough.
Maybe Capt. Bahi know an awful lot about shipbuilding but, as he says, is new in design. That does not disqualify him to select the material and engines for his boat.
I have seen, for example, that in Egypt prefer steel fishing vessel before GRP. 15 or 20 years ago, in Lybia, they thought of building a major shipyard for steel fishing vessels, because they would not continue buying Egyptian wooden botas. The project did not come to fruition, but came to the shipyard to buy heavy machinery. I've seen pictures of cutting machines CNC in the harbor dock.
There is no reason to suppose that what is obvious to us is not for others.
Cheers.

 

Capt Bahi, 3 questions for you?
What do you consider sensible price/metric ton for constructed (finished) boat with everything included?
What is the largest boat you have previously owned?
Are you asking for advice on defining/refining your brief for a designer or do you plan to design it yourself and are asking for help in the actual design process?

 

1. Approx US$1475/mt (finished with everything included)
2. Aquasport Osprey 170 with Yamaha 115hp outboard engine
3. I'd prefer to design her myself

 

If you are considering 15Kt cruising speed on a boat that size in steel, it will require a lot more power. Knowledge of building is what makes designs better. Theoretical knowledge without the practical one, usually creates faulty designs that are difficult and expensive to build. There may also be some miscommunication between what you call a sportfishing boat and what the usual description means. They are fast boats capable of operating in rough offshore conditions. Search Carolina Sportfishermen and you will understand what I am referring to. The cruising speed is at least 30Kt with top speeds over 40.

 

US $ 1475 per tonne to a 'turn-key' stage?. What a deal!

 

Yes, the boat price may be higher than estimated 10 times.
Gonzo, if you read what has been published Capt. Bahi, with a minimum of attention, you will see that the text and the picture he includes in his post # 1 describes exactly what for him is a sport fisher 60 '. I'm pretty sure it's the same ship that you're thinking. Although you have deduced that he has no experience in building and knowledge, if any, are theoretical but not supported by practice, the type of boat he describes is very clear.
Another point to discuss, if you continue reading carefully what he has written, he'll talk about his boat will have a cruising speed of 15 knots. I do not know, then, why do you speak of 30 knots cruising speed and a maximum speed of over 40. What boat do you speak?
As I said before, imo, we should advise the Capt. Bahi on the best way to achieve their goals (if achievable), not ours.
Gonzo you tell us to have built many boats of some kind, but that, to Capt. Bahi, will not help much. You should take all this vast experience you have in other boats to tell, if you know, how it is constructed, not designed, Capt.'s boat. On the other hand, if one has no experience in the design of ships, it is unlikely that his advice on how to design ships is useful for anyone.
Always willing to clarify things and to help.

 

It seems that either nobody is willing to help, or nobody has the knowledge, in this forum! Just negative talk without alternative solutions, which I can easily find anywhere in the world.

 

Capt.Bahi, you are partly right but on this forum there are qualified people to help you, although some of us like disturbing others and try to show the world, with half-truths, how great is our knowledge.
The first thing you should have is a SOR, a GA drawing and a lines plan. If you have that, I will make naval architecture calculations. I say that I will do them because it is necessary to have special software that probably you do not have. Next you are to make calculations of scantlings, which is a little more complicated and laborious (imo). Chances are you need thicknesses greater than 6 mm for some items.
All this, and more things that are necessary, there are people on this forum can do them, but have not yet participated in this discussion. As I said before, I offer myself to help in that regard.
In any case, you ask the potential helpers to show you examples of their projects afloat, not on paper. Many detailers and few designers.

 

TANSL I quite strongly disagree with your ideology. We shouldn't be here helping people to waste time on unrealistic or ill-informed dreams. I truly don't mean to be cynical but its NOT helpful to "be nice" if it means that the correct information or true realities are being withheld.
I face this on custom motorcycle forums. There is the "positive" ideology which means that all kinds of ill-conceived ideas are getting pats on backs and encouragement - even when it means that the bikes are made to work worse, potentially dangerous and the work itself is made harder by bad calls.
The other philosophy is to to tell the fresh person answers even to the questions the person is not (at least yet) knowledgeable enough to ask. The latter is much more fair in my opinion.

Bahi is an adult if someone feels mean I am sure he can ignore it but people are raising serious concerns in this thread. 60ft boat built from 6mm steel is NOT a logical next step from a 17' 115hp outboard center console. 60 ft boat is NEVER someone's 1st design job. No good boat will come out of that. I think I can pretty safely state this as a fact.

And it is no disrespect towards you Bahi. Designing a successful boat of that scale takes serious expertise - including experience. Many of the questions you ask show that you are thinking that there are shortcuts to the process. I am afraid there aren't - to become a boat designer you need to acquire the experience and knowledge of a complex and challenging profession.

Also I think you have unrealistic ideas of the building cost, operating cost and maintenance that go with a boat of that scale. I don't have a good idea either - I am a total amateur really.

Custom boat is always way more expensive than used existing boat (even after some refreshing).

 

Thanks Kerosene - I agree with your comments - you've saved me some time.
My dismissive comments earlier about the Bahi estimated price (Approx US$1475/mt (finished with everything included) was perhaps not the best. Here in western Canada I would have considered $30/lb or about $66,000 per m.tonne. If the boat weighed/displaced 100,000 lb (45 m.tonne) the price would be around $ 3,000,000.
I know there are price differences around the world but a spread factor of 44 is quite substantial. Perhaps it was suppose to be $14,750/mt ?
As to performance: with a good semi displacement hull form and 2 x 300hp a rough guess would be a maximum of 13 knots

 

Kerosene, I find it very interesting that you disagree with my "ideology." The exchange of views, with different ideologies, comes the light. Somebody in this forum said that you never learn from your successes. Therefore, direct me what I am wrong to learn something.
It had seemed that Capt.Bahi believed that no one here is able to help and he did not want more negative comments about his project. I tried to explain that too, in this forum, you can get positive comments and support.
Really, Kerosene, I do not pretend to be kind and friendly, I intend, if I can, help.
I do not understand why this project may be unrealistic or "ill-informed dreams". Here I need some additional explanation yours. Capt.Bahi may have some starting hypothesis wrong but I guess if you explain well, he will be able to change his mind.
JSL's comments seem more positive, give more light to the discussion, and, apparently, we are approaching 15 knots Capt.Bahi needs (with more engine, of course)

 

Kerosene rightly points out that a software program is not going to make him a shipwright. It takes a lot of time and experience to learn, not just how to build, but to manage a build.

 

How right you are, Gonzo, but, to my knowledge, Capt.Bahi has never said that he pretended to be a shipwright.
You have introduced a nuance that is very interesting: to build and how to manage a build. I do not see how anyone can think that knows how to build a boat if he does not know how to manage its construction. Maybe I'm misunderstanding. More explanations, please.

 

I feel like waisting my time, but the estimated cost in Egyptian Pound is: (US$ 1 = EGP 7.80)
- steel cost = 20 ton × 5,200 = 104,000
- construction of steel = 20 ton × 2,500 = 50,000
- wood cost = 110,000
- construction of wood = 40,000
- engines cost = 130,000
- generator & electricity = 30,000
- plumber & materials = 30,000
- paints = 75,000
- chart plotter, fish finder & VHF = 15,000

Hull weight = approx 20 ton / Total displacement = approx. 50 ton

In regards to the engine, the rule is:
- for full displacement hull: average power requirement is 5hp/ton
- for semi-displacement hull: average power requirement is 10-40hp/ton
In my case, a semi-displacement hull of approx 50 ton would be in need of average power not less than 500hp & not more than 2000hp. As advised, I think of using 2×375hp.

 

Regarding the steel sheet thickness, kindly check this thread
http://www.boatdesign.net/forums/metal-boat-building/steel-plate-thickness-6750.html

My above calculations were based on 6mm steel sheets. Now, I believe that I may cut cost by using 4mm sheets for the bilge & 3mm steel sheet for the upper part.