How long does it take to design a hull

Hello

I would like to have some help in determining how long it will take to design and optimize the hull for an 8 m long sailing yacht. It is assumed that the person who will do the job is familliar with the software. I only need a ruff estimate to be able to calculate the estimated cost for the project.

I would be very thankfull if you could help me to solve this issue as soon as possible.

Regard
Henrik

 

That is a loaded question (lots of dependencies),

I am an amature and I have been working on a 9.5m boat desgin for the past 14months... I wanta do it right.

I am developing a spreadsheet which will give me scandlings and all the pertinent information. I have also built a first pass, 1/10 scale model, plan on building a second model, which will be the final design before I start going through the detailed costing. Right now I am just saving money as fast as I can, working a second part time job so I don't have to spend the next 10years saving.

From listening to the pros on this forum, some of them have the spreadsheet done, if they are smart about it.

It depends on the individual designer......., and his experience.

There are some good ones on this forum....., and I am curious also how long these guys would take to do a 8m design.......

 

Henrik,
Are you talking about the shape only, or do you want a complete design?
Steve

 

I am talking about a complete design.

 

Being an amatuer I couldn't possibly answer, but the question needs to be refined if a reasonable answer is to be had I think.

A simple 8 m boat based on traditional scantling rules without to much weightoptimazation and simple standardized rigging. Simple all plastic interior wit just a few molds to do it.
That ought to be pretty fast

A weightoptimized racer OTOH is obviously another ballgame, as is a cruiser with full wooden interior with a full set of constuction drawings for every part of the interior.

It will also depend on if the designer alreday has a design that is close to what you want already and can be streched or modified to suit your needs.

As with anything you want to "buy" you get better answers if you know and closely specify what you want.

Swedish comments:
Vad säger du nu då Henrik? Har du sjösatt ännu?
Själv väntar jag på våren! Har lådan fått fönster ännu?
Intressant fråga, men du får nog specificera lite mer tror jag

 

I'll take a stab at it ...

For a somewhat standard boat with no innovative features such as canting keels, with industry standard construction (no exotic materials or methods) and presuming off-the-shelf hardware, and the drawings being prepared for a boatbuilder experienced with this type of bat and construction, I'd expect 125 to 150 man-hours of design time. If this is to be a competitive racing boat where much less assumption and much more calculation is needed, I'd at least double that estimate, maybe even more.

The devil is in the details, and the details take time.

 

I feel that I need to refine my question. When talking about designing I am only talking about the hull form and not dimensioning of the structure.

The yacht will be more of a racer than a cruiser.

 

Hello Henrik!

As I live in Sweden and have recently built a boat, custom designed for me, I think I can give you some answers. A ruff estimate is that the design is about 10% of the total buildig cost (material cost if you build the boat your self). Take a look at my project at http://vsrt.seglar.nu and if you wish, feel free to contact me by mail: backyardboatbuilder@telia.com

And some Swedish for ErikG...
Jag tror du tar fel på Henrik och Henrik

 

Al ot depends on the builder, as well. I have always reckoned that a full-on Open60-type project, with all the "i"s dotted and all the "T"s crossed, with a biuilder that needs to be told everything, would take about 1000 hours.
If the builder is very good, and you trust him and he trusts you, and if some of the details are taken care of by the owner (electrics, plumbing, etc.) that estimate could be reduced by 50%.
This sounds like a lot, but it is backed up by hard data from previous designs. As a percentage of building cost, it isn't too bad. Assume a rate of $75 per hour (I WISH!!), and you have 75,000 bucks for a design. If you think you can build an Open 60 for $750,000 brand-spanking-new, let me know which builder
Smaller boats would seem to demand less hours, but in the Open classes, you still have to design a hull, a rig, and an interior for one person. As a result, I always quote less for smaller boats.

Steve "does NOT charge that much for design work "

 

For my design, a custom 33-ft IMS, the 10% estimate is quite accurate, this is based on the material cost, build myself.
When looking for a designer, I was offered custom designs from several well known designers around the world. The price tag for a 33ft hull, deck, sailplan, keel, rudder, scantlings and a rough interior layout drawings was in the range of 4-5000$

 

Speaking hull shape alone:

If the boat is a racing yacht, it has to be optimized against the rating rule and possibly the planned campaign. This can take as much as you can afford, for example, CFP, VPP optimization, model tests, etc.

On the other hand, you can knock out a quick and dirty guess in a day or so. Note though, that you have to be able to make a good estimate of weight first, so that the hull shape can carry it (stability too), but the hull size affects the weight, which affects the size, so some experience is in order so that your design spiral gets smaller, not larger.

Then you have to do all the rest of the bits and pieces, which takes a lot longer than just the lines drawing, but as noted, you have to have a pretty good idea of many of the pits and pieces to do the hull shape.

 

I think Henrik's "price tag" is a good, reasonable indication of reality
Yes, 1000 hours can be spent, but the market cannot bear many of those boats/year, spread around all the designers in that field. Mostly, I find I'm charging 30-40 per hour, with a "penalty" drop in hourly rate if I exceed the guestimated number of hours. It keeps me honest, and the owner doesn't have to part with an arm AND a leg if my estimate is off. Usually I come in just under or dead on the number of hours quoted.
Steve