Duca D Acosta build lay out and Zboat

Looking pretty good, but it seems like your waterline is kind of light. I presume you float tested it - how much did it weigh?

 

The water line is from the plans. I will float test and weigh it. Do you think the waterline sgould be lower?

 

Hmm. I'm trying to think of how to say this. The rules regarding weight were revised a long time ago when we adopted CO2 as a propellant. There was concern about smaller boats being able to carry a regulator, bottle etc., so it was decided to allow them to add 1lb (regulators weighed a lot back then), and an additional 25%, and deepen the hull shape as appropriate to match.

As a result, in small gun, it's possible to legally weigh your boat down to the point where it will not actually float. Or not float and move at least. This was demonstrated quite effectively at Nats last year, with a Duca.

So, if you look at the IRC ship list - http://ircwcc.com/main/shiplist/ - you'll see the Duca (listed as "Filbertino" or something like that) is allowed to weigh a stupefying 12 lbs. The hull for the Strike model is scale, so it just will not float at that weight, it's just silly. You'll see the same for many other small ships, and people have done things like deepen their hull by 3/8, etc. to make it work.

In your case, you marked the waterline according to the plans. It's okay, it's a mistake we've all made before. Plan waterlines are often marked at 'light load', so if you use the marked waterline and build your boat to that, you'll end up giving away a lot of freeboard and target area. We've all done it before... I think. I know I have.

If you look at the Wiki for the Duca, it lists it's full load displacement as 10,539 tons. Presuming that is long tons, or whatever the naval thing is, the math if I recall correctly goes like this:
10539/1333 = 7.9 lbs. That's the scale full load weight. Hmm. So, just to double check, (7.9+1)*1.25= 11.13, which isn't 12. Hmm....

Okay, another ship list shows 11,500 tons. So, 11500/1333 = 8.6 lbs. So, (8.6+1)*1.25=12. That explains that.

So, anyway. I had a French CL (Le Mars) that was very similar to the Duca in size, and it was really happy around that 'scale' weight. It was also able to carry the needed systems at that weight point, so that was a good thing.

What I would suggest is that you gather all the equipment you need, and weigh it, along with the ship components, and see what it wants to weigh. Then, put that amount of weight, or maybe 8.6 lbs in the hull and float it in your tub and see where the waterline actually is. If it looks too low, lighten it, but it probably won't.

Honestly, I have one of these kits myself. I really should have built it by now. I feel guilty. I'll try floating it and see if I can send you a picture later/tomorrow.

 

Commodore and Greg
That's some good info. I should have realized the waterline always changes. I have built boats before, wood and fiberglass hulls, and the water line has
never been as shown on the plans. I am waiting for items to arrive so for now I will have to put things on hold. I have a medical procedure on May 5th. Thanks for the infor.

 

Just a quick update. Still waiting for parts from BC, working on guns (3d printed) ect. If the guns are a .5 unit, does that mean I can have four double barrel guns on this ship?

 

Yes, you can, but you don't want to do that. As a beginner, trying to keep two working is difficult enough. Four is just crazy. Also, each one must have its own solenoid valve and other equipment, and that quickly results in weight problems.

We had a veteran battler try this with a Duca at this last year's Nats. It didn't go well for him. The poor boat made it maybe 20 feet before it rolled over and sank from the top weight.

A long time ago, a kind fellow by the name of Tom Jass taught me about a thing called the KISS principle. If you don't know what that means, it's "Keep It Simple, Stupid". It's better to have something simple and basic that works every time, than to have something high performance that works "most" of the time.

(The rest of those times, well, that's when you get your pants wet.)

 

NO won't have 4 working guns. My plan now is just one maybe two in the stern. Yes simple is much better and that is my plan. I have been reading through the forums and asking questions to get a understanding of everything. Thanks

 

Oh, very good then. I'm afraid that some of us are jaded from seeing too many people go ahead with a bunch of preconceived notions, and then wonder why they have problems.

I want people to be happy and have fun, and speaking from personal experience, having a boat that actually worked (only took me a few years) was such a great thing.

In my case, it was more a case of cheapness and being a poor college student (yeah), but yeah, stuff happens. I also happened to run into some nice folks like Bob Amend and Will Montgomery who helped me learn a lot and fix some of the problems I had been having, like a single pump screen (getting clogged), and guns that didn't work very well (sprung pistons work much better than ball bearings, you know).

You know, basic stuff like that...

 

Quite all right. I will take all advice and criticism, this stuff is new to me.

 

Weight is 8.4 lbs. Cuts are the o’s.

 

Thanks Greg. Now the fun cut it all out.

 

That looks a lot more reasonable. Just a hint - drill some holes in the corners before cutting, that way you'll be much less likely to cut through the actual rib areas.

 

Thanks all will do. Will post pictures.

 

Any suggestions for cutting out the windows. A dremal works but what a mess.

 

A dremel is the best way. Get a shop vac and set up the hose so you can cut right next to it. Long sleeves. Hat. Gloves. Dust mask.

 

That's what I thought. This will have to wait until cooler out(project is now an outdoor thing).