Rik van Hemmen's blog

Last year I was contacted by the Philadelphia Section papers chairman of the American Society of Mechanical Engineers, who asked if I could make a presentation at a joint ASME, SNAME, SAME section meeting in Philadelphia on January 24, 2017.


I told him that, in principle, I would love to do that, but wondered what subject he was interested in. He thought that a presentation on cruise ship power plants might be of interest to the membership of the various societies that might be attending.


In our quick discussion I mentioned that this subject is a book size subject and what part of it would be of interest, and he indicated that a more general discussion would be fun. Without thinking about it much further I agreed, but after putting down the phone I became a little worried. read more »

Rik van Hemmen's picture
Wednesday, January 18th, 2017

TBT, County of Edinburgh Stranding


Point Pleasant Beach is a few miles south along the New Jersey shore from our office, which is where, on February 12, 1900, the County of Edinburgh ran aground.


The vessel had very little damage, but then, as now, the stranding quickly became a tourist attraction.

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Last year I started this list with lots of space flight issues, but when I made my list this year I started with aircraft technology, and then immediately shifted to maritime in item 2. It has been a strange year and that is why I ended my list with a repeat and enlargement of item 8 on my 2015 list; devastating ignorance.


I wonder why I ended up having 13 items this year.





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Holiday presents are always difficult to choose. I suppose a present is a two way street; it should delight the gift giver and the gift receiver equally. To find something that fits that bill is always a challenge.


Then to choose a Holiday present that suits everybody and that can be delivered over the internet is even more difficult. 


In thinking about that I am giving all our friends and clients all over the world at land and sea a copy of David JC McKay's book "Sustainable Energy, without the Hot Air".


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Halloween is quite an important commercial event in the United States (Annual US Halloween sales amount to US$8.4B, about the entire NASA manned space budget), but the maritime community has had a hard time breaking into this industry (The pirate costume licensing fee thing never worked out). Still, that does not mean there are no opportunities. 


Possibly the best business opportunity is pumpkin boat building. Pumpkin boat building has been taking place since at least 1996, but the level of technical improvement has been disappointing to say the least. It is obvious that naval architects have not been involved in the development of this type of vessel. It probably makes sense for the Naval Architectural community to have ignored pumpkin boats for the last two decades, but now it appears the moment has come where we should start to look at these vessels as a potential business opportunity since the construction material appears to have matured.

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When we talk about efficiencies it often becomes difficult to figure out who benefits from the efficiency. Airlines may be as efficient as they can be (spend the least amount on wages and fuel per passenger moved) but that does not mean that airline travel is efficient for the passengers. They may stand in long lines, be shunted through airports they do not want to visit and fly at times they do not want to fly. In other words, from the passenger’s point of view, each airline flight is often very inefficient.


Efficiency needs to be evaluated at a system level and the point of view needs to be defined. In 2009 David JC MacKay (1967-2016) wrote a wonderful book called “Sustainable Energy - without the Hot Air” and in that book he very carefully describes present day energy efficiencies and provides guidance on what efficiencies can be achieved. The book received very high praise and he was appointed Chief Scientific Advisor to the UK Department of Energy and Climate Change. However, he made a very interesting error in his analysis.

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It is always important to ask “why” about every detail in every design, since bad design imposes a penalty on every user for the life of the bad design. 


Bad design can hang around forever even if good design exists. I often ask “why?” when I am forced to use a badly designed cleat on a boat when we have a near perfect design in the 100 year old Herreshoff cleat.


We don't come across enough of these "why's", but I came across a nice one a few days ago.

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This is a Guest Blog by our U. Mich summer intern Sam Edwards.


I was handed off progress on Project 114 by a previous intern in the office. He had added in a feature to plot the sections of files that were input to the “Hydro2A” calc engine as well as started the design of a “Marine High School Research Vessel”, or MHSRV. My goal was to continue tinkering with Project 114 as well as to continue design on the MHSRV.


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In March of 2015 Solar Impulse started its around the world adventure and today it brought the adventure to completion; an around the world flight entirely on solar power. As I noted in an earlier blog this is a first order achievement that has only occurred a few times in human history.



Still it is difficult to make real sense of this achievement at this stage.

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The Maxi Taxi concept describes the advantages of convoying in saving fuel during highway travel. Cars that closely follow each other can achieve impressive reductions in total air drag. Air drag is the leading overall drag component at higher speeds and therefore represents the lion’s share of a car’s fuel consumption at speed.



Air drag is a complex subject, and the original maxi taxi concept aimed to reduce overall air drag by fitting a number of cars as close together as possible and thereby to create a drag profile that is similar to a railroad train, which is basically a flexible tube that is being dragged through the air. We can achieve a similar effect with car convoys and the cars do not have to be the same, but equal width would be real a benefit.

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