This is how much sailing yachts cost.

You're right, but maybe you could use the Cubic Number (L*B*T). We use this to figure out costs/value for fishing vessels in a first design stage or when appraising, based on a similar vessel's cost. It works. Maybe it could work here too.

 

Guillermo,

For what it is worth, I plotted Cost vs. LBD and attach the plot. It does give a reasonable trend which might be of use to some, although the scatter is similar to Cost v. Length or Cost v. Displ. LBD is related to Displacement so one would expect a similar sort of plot. The trouble with using Cost v. LBD in a cursory way is that you have to calculate LBD for any given vessel before entering the plot, and LBD is harder to visualize than simple Length or Displacement. Also, to be more accurate and more indicative of the volume of the vessel, one should use Lwl x Bwl x Draft, or Loa x Boa x Depth (preferred, I think). Unfortunately, Bwl and Depth are almost never published, so the data is not readily available. Within one design house or for a single manufacturer where this data is readily available, then it could be quite useful.

Thanks to Brian Eiland for your chart. You and I have talked about it in the past privately. For building in a cheaper labor market in a faraway place, one should include the cost of monitoring construction which is a real and direct cost. As I mention in my article on my website "How to commission a yacht design and have it built", not every design detail and spec can be covered in the design documents. Many things are left up to later decisions on the shop floor. And human nature being what it is, we all make mistakes, we change our minds, and we think of improvements along the way.

These all have impacts on other parts of the design, and decisions have to be made to build the boat correctly, on time and on budget, or as closely thereto as possible. That requires that the owner, his/her naval architect, and/or the project manager be on site to handle the decisions. To be there costs money, real money added to the cost of the project, and oftentimes this comes out to more money than is saved by cheap labor.

One also has to think of equipment, and locations of cheap labor do not necessarily have sources of the proper grades or brands of equipment. These have to be imported to the locale, and that too adds to the overall cost.

Every boat building situation is different and should be analyzed accordingly for the best possible combination of cost, time, and quality. That, as I say in my article, is part of the adventure after all.

Eric

 

I have been looking for prices of boats for sometime, and it seems to me that The Koopmans look pretty accurate to me, but I don’t think it applies to the majority of boats sold in the market (up to 50ft in length).

Koopmans’s boats are expensive, with very good interiors. I think that those prices apply to the Top of the range production boats (Halberg-Rassy, Najad, Southerly, Island Packet, Malo, Arcona, Cabo Rico etc.).

It seems to me that custom boats cost a little bit more (including the project), but I believe that most of the boats sold in the market are Beneteau, Dufours, Jeanneau, Bavaria, Hunter, and the like, and these cost a lot less than the average in the graph.

 

Hi Vega,

The data in my spreadsheet includes many production boats sold in the US, including Halberg-Rassy, Najad, Island Packet, Cabo Rico, Hunter, Beneteau, Jeanneau, Bavaria, Oyster, Moody, Kanter, J-Boats, Tartan, X-Yachts, Catalina, Caliber, Cigale, Shannon, Hanse, Morris, Santa Cruz, Pacific Seacraft, Amel, Wauquies, Saber, and Saga, to name most of them in no particular order. So there is a full range of quality and price, production and custom in the list.

Eric

 

Hello,

Eric, I think that I was misunderstood. By the way, I have appreciated your Graphs. It is an interesting piece of information and thanks for making it available.

What I mean, is that if you take the number of all boats from each brand sold in the USA last year, the number of Cigales, Santa-Cruz or Cabo-Rico, is minimal regarding for instance the number of Beneteaus. I do not know well the USA market, but probably, Bavaria, Hanse, Hunter, Beneteau Group and Dufour have probably sold more boats than all the others put together (and those are relatively inexpensive boats). What I mean is that this is not showing in the graph, regarding the average price of a boat.

 

L*B*H (Not T, or D in your notation, sorry) takes into acount the total volume of the circunscribing parallelopiped to the upmost continuous deck, not to floatation. It works well only when comparing quite similar vessels, this is, of the same type and not very far away dimensions.

Thanks for the plotting you've done with this. Dispersion is quite the same than for the other data, as you state, so of not better use. I agree with you that not having better data, LOA is the easiest way of facing the issue.

Anyhow, could it be possible (and useful) to categorize your boat's database packaging boats by types (or qualities) to try to find out if dispersion is less?

 

As Guillermo knows, I've been writing a fishing boat optimization spreadsheet based in part on the work of my teacher, Cyrus Hamlin. Cy always used CUBE (cubic number = LWL x Beam x fairbody depth amidships), as the dimensional corrollary of hull/deck construction cost, and in early versions I did the same.

More recently I've been using:

(LB + LD + BD) * Displ^(1/3) * 1.275

where:
L = LWL
B = Beam (max)
D = fairbody depth amidships (rabbet to top of deck at side)

This is derived from the surface area of a box of these dimensions, which would be:

(LB + LD + BD) * 2

Since static pressure and therefore panel strength/thickness vary with displacement, I multiply by displacement^(1/3). The result scales as a cubic value. Since the result gets multiplied by a cost per cubic unit factor anyway, I changed the constant, 2, to a value that would give a similar result to the cubic number for the heavy displacement fishing vessels I was considering (allowing me to use the same cost per cubic unit factor).

Do you see any problem with doing it that way, Eric?

 

Oops. I made a mistake, Alik. I've now edited my previous post so the expression is correct. It's a sum of areas multiplied by displacement^(1/3). The logic is that, when buying material, it's a sum of the areas you are generally using. Multiplying the sum of the areas by displacement^(1/3) makes the result cubic.

I've read several places that doubling the freeboard adds less cost than doubling the length. That made me think there was something not quite right about CUBE = LBD as the function correlating with cost.

There are some previous postings that I'm still reading through. If I have not yet understood something said previously, please forgive.... I'm working on it.

Retired U.S. Naval Academy professor Bruce Johnson has tried to persuade me I should be using T instead of D for fairbody depth. I've been using D because the versions of ABS I've used use upper case D for depth, and lowercase d for draft. T means time to me.

Cheers,
Stephen

 

Stephen,
Your formula probably has some merit. The overall dimensions LB, LD, and BD, necessarily set the equation to rectangular areas, which is then influenced by the multiplier 1.275. To my thinking, I would probably put some kind of block coefficient into the equation to reflect actual surface areas, and then I might expect the multiplier to go up. If you seem to get reliable trends with your collected data, then it probably works. The point of the exercise is to have a reliable estimating tool for future boat designs, so that you can estimate closely what a boat will cost based on arbitrary given numbers.

Vega,
You are correct, my graphs do not reflect the average prices of boats over the whole population of boats on the market. It is nearly impossible to get those numbers, and I would suspect that the data would be pretty suspect, biased, and not at all uniform. But that is not the point of my graphs. What I want to show is the variance of price to boat size for one example each of each design using overall and readily available dimensions. It goes so far as to include boats from all over the world, both custom and production. As one would refine the data, for example, doing custom boats and production boats separately, one might find a further refinement and narrowing of the graphs.

Eric

 

Sorry to resurface an old post... Has anyone done a similar cost/length study for powerboats?

 

Hi fpjeepyo5
I received a notice by email that this thread had a new post--um, over 14 years after the last post! I am sure that if anyone had a continuing interest in this thread, you would have seen more posts in the interim. Likewise, if there was an interest in powerboat design and associated advertised costs, you might have seen something here. There might be other powerboat sites or cruisers forums directed towards powerboats that might have some study like this.

One thing I have noticed for some years is that boat reviews in magazine have stopped publishing the prices of new boats, so it became harder and harder to collect published data. Without reliable data, there is no study.

For those who are interested, I am still on the planet, down in Australia. We got stranded here an extra year because of the COVID-19 pandemic. Corroboree is holding up well. We did a major refit in New Zealand in 2018-2019 and toured the country by car. Same here in Australia, arrived in May 2019, toured much of the country by car and airplane, and now we are up inside the Great Barrier Reef at Townsville, Queensland, making preparations to continue our circumnavigation. We have a haulout scheduled for mid-April to refresh bottom paint, then we continue north in May. We'll be heading across the Indian Ocean in July-September. If you want to track our progress, you can log onto our Garmin Mapshare here: https://share.garmin.com/CORROBOREE. Likewise, my wife, Arliss, writes a blog about our trip which you can see here: The Old Woman and the Sea – Arliss Ryan https://www.arlissryan.com/blog/.

 

Sorry to spam you via email.

I feel like the only people that would benefit from the information I'm looking for are designers, builders, etc. I'm guessing powerboats follow a similar trend as your sail calculations and $ is roughly proportional to LOA^3. If a builder has a 30ft model and they want to make a 24ft model (20% smaller.) Then they should plan the price to be roughly half of that of the 30ft. (0.8^3=0.512) Materials will be less, you could make an argument for or against half the materials. Same argument for hp requirement and engine cost. But the stickler I see is labor. Running a wiring harness whether it is for a 20hp or a 600hp is going to take about the same amount of time. Spraying paint on a boat that is 20% shorter isn't going to take half the time. I think this is why we see different construction methods for different boat sizes. It makes more sense to infuse a 70ft boat than a 15ft. Riveted aluminum boats do well below 20ft welded does better above. The budget allows a liner in bilges on larger boats, but only gelcoat on smaller boats.

Thanks for the life update. I'm glad you are doing well. I noticed you hadn't been on the forum in a while.

 

Hi fpjeepy05,
You score well on all your arguments. And because so many elements take different amounts of time to perform or install, so variances will appear from item to item, builder to builder, and even from region to region.

Of the powerboat designers I know, they may very well have conducted cost studies for their own designs, and maybe the market in general, but I have never seen any data like that published. And as time goes on and the popular press continues to NOT include price data on the boats they review, so it is increasingly difficult to collect and analyze costs.

One rule of thumb that I and others used in estimating labor costs is based on the overall weight of the boat. An efficient production builder will be able to build/install 5-6 lbs. per manhour. The average builder will fall into the range of 3-4 lbs. per man hour. A custom builder will complete his boats at the rate of 1-2 lbs. per manhour. So, for average labor costs to build the boat, divide the boat's weight by one of these rates to see how many manhours of labor are required. Multiply that answer by the builder's chargeable hourly rate and you get the cost of labor for that boat.

When I retired at the end of 2015, I had accumulated 14 years of active membership on this forum. It was good fun, and it helped promote my design business. But as I was busy enough getting Corroboree ready for our circumnavigation, and with a sense of "been there, done that," I did not feel compelled to contribute as much as I had before. I also sensed that the same old arguments and requests were coming in, stuff that I had already answered before, so I did not have a compunction to keep going on with it. I did not suspend my membership at BoatDesign.net, however, and I do check in from time to time to see what's going on. I still get plenty of requests for help on all sorts of subjects from people chiming in through my website, and so I am pretty free with my advice, and that keeps my hand in. I do not miss designing boats and masts, or writing up complicated boat repair specifications. I have plenty to look forward to just getting this boat to sail around the world.

Cheers,

Eric