Prototype -- medium-large aluminum v-hull

M

Matthew R. Snyder

Active member
As regular readers know, I really like Lund Alaskans for what they do well: Big payload-to-weight ratio; ability to carry a large amount of people and gear across big waves and into shallow places. I have been thinking for a few years that I'd like a boat that's a little bigger than my 18, and I don't like the way the 20 Alaskans fall apart, so I've decided to design my own. I've spent some time measuring various years and sizes of Alaskan, the 21' and 22' starcrafts, and Winninghoff's BWDB and came up with this:

It's nine inches shorter (at 19.75') and three inches narrower (at 87") than a 20 Alaskan. Deadrise (10 deg.), chine width, and transom width are proportional to an 18. Entry's a little sharper forward and the sides are about 3-4" higher, which split the difference between the Alaskans and the other boats (the Winninghoffs and Starcrafts have nice high sides but are a handful in a crosswind). Splashwell is omitted in favor of a bracket. Power will be a 115 hp Yamaha or better yet a 90 hp if the boat comes out light enough. 3/16" bottom.

I had the engineering tech students here at the college draw me up an Autocad prototype from my crude pencil drawings. I'm going to refine it and then use it as a basis for requesting bids from a several boat builders. The dimensions aren't set in stone, but the drawing gives me a way to express my ideas to prospective builders. It'll be up to the builder to apply (hopefully superior) knowledge to the lofting. The pdf is attached (it's actual size, 24" wide ... it can be viewed onscreen at 20% zoom).

Take a look at the lines and tell me what you think/what questions you have?

View attachment 06_27_12 MRS duck boat prototype.pdf
 
Matthew, Good start, you really have to draw in the chine on the profile or side view and the top or plan view. From this information you can decide on how far apart you want your stations, and proceed to plot out your body plan or front view. Rich
 
The dimensions aren't set in stone, but the drawing gives me a way to express my ideas to prospective builders. It'll be up to the builder to apply (hopefully superior) knowledge to the lofting. The pdf is attached (it's actual size, 24" wide ... it can be viewed onscreen at 20% zoom).

Take a look at the lines and tell me what you think/what questions you have?
Click to expand...

If you want to adde some usable room to the front section of the deck, right now it tapers sharply. I suggest you add in a carolina flair to gain more front deck area.
The picture below shows it better than I can describe.
CS25_pl.JPG

 
Joe -- Frontier is laid out just like a 20' Lund Alaskan. I wouldn't be surprised if Brunswick helped with the "sharing." I thought about buying one, or a 20 Lund with which I am very familiar -- my dad and my cousin both have them. I like them but for the money, it doesn't give me that much more room than the 18 Alaskan I already have. This design is intended to carry more decoys in a smaller package than a 20 Alaskan or 21 Frontier, with a few inches more interior freeboard. If I can't get a boat like this built for what I want to spend, I will be looking at either a used 20 Alaskan (to customize) or a new 18 Alaskan.

Rich -- You're right! My original drawing had the chines, but I guess my student conscript labor couldn't figure out what a chine is or how to draw one in CAD. I can describe the concept ... Side chine is a dead-nuts match for the 18 Alaskan, just altered in proportion to the size of this boat, chine is low on the hull and almost as wide as the gunwale width for the aft 60% of the hull, then it rakes sharply up and narrows. In other words, the small deadrise and wide chine width start at the stern and continue forward without tapering much for the first 12 to 14 feet; then narrow and elevate sharply forward to provide for a sheer entry. The Winninghoff's lines are similar, just more exaggerated than I need. The idea is to provide some relief in steep waves, while preserving shallow draft. Or at least, that's how I'm going to try to describe to builders, unless anyone has a better idea. Drawing the chine would probably be a good start. I've got Hulls software and I'm going to try playing around with it now that I have this drawing as a starting point.

Jeff -- I've fished out of a couple boats like that and it's really useful for certain conditions, especially casting. Plus it looks cool as hell. But almost all of what I want to do with this boat happens aft of the helm. In our current boats I can run the boat and deploy the rig single handed -- just turn around, grab a basket of decoys from behind me, and toss them over - which I couldn't do as easily if I had to leave the helm and walk up to the bow to get more decoys. One of my design goals is maximizing space aft of the helm. The console's pushed further forward than you see on most boats, and the splashwell delete/full height transom give me more room for decoys. I expect to be able to carry as many decoys aft of the helm as a 20 Alaskan or Frontier will carry in the entire boat.

I'm a little concerned about the effect of the bracket on static trim and/or swamping the motor when coming off plane in a following sea. But it seemed like the best solution for maximizing space aft, and I can start with a higher motor height given how far aft of the transom it will be mounted. I'm not exactly sure how to compensate for it, other than I might need to locate batteries or fuel tank further forward than I would like. Anybody ever dealt with this?

Thanks for your ideas guys ... this is helping.
 
Can't help with ideas or anything but just wanted to say that's really neat hope it works out and you get your boat built the way you want
 
Thanks ... I'll keep the site posted through further development of the prototype plans, spec and bid, and the build. I have learned a great deal about lots of kinds of boats over the years but this learning curve is even steeper and more interesting.
 
Matt, one way to keep the motor up is to have a wider beam. 83" is NOT that wide by todays standards with boats with brackets. I personally would want the boat wider, but that is just me.

either way, best of luck to you on this, will be interesting to see it built.
 
Yeah ... some of the numbers on the students' drawing got transposed a little. (damn i wish i knew how to draw in CAD!) so the stern-on view numbers are all wrong in the drawing. I think I am going to have to go a little wider than I had first planned (to as much as 90" max beam, 84" transom width, about 78" chine width astern) to float it.

I'm trying not to make it too wide -- a wider boat takes more hp but I don't want an outboard any heavier than a 115 because I won't be able to drag it on and off the beach myself -- but if the boat squats too much at the stern when it's beached because of not enough aft displacement, it would be just as bad.
 
Matthew, get out a some paper and pencils. the cad equipment cant do a single thing by itself! If you dont have a set of curves use a fishing rod blank to plot out your fair curves. I have had an old lamiglass spinning rod blank that I have used for drawing sheerlines.and other curves on my boats for over thirty years. Check out my web site and see what you can do with pencil and paper. www.tributeboats.com. By the way I draw my boats to one inch to the foot scale, easy to work off later during the build. Rich
 
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