Design failure
The Haarlemmermeer class drew a lot of criticism in the 1862 investigation of the navy by the Dutch house of representatives. Captain-lieutenant A.R. Blommendaal thought the Haarlemmermeer a vessel for so many goals that it missed all. Captain-lieutenant J.A.H. Schreuder probably referred to both the Hector class and the Haarlemmermeer class when he stated that "the flotilla vessels are failures for their purpose, and of no use. They have too much rigging, are too tight, and draw too much water for coastal defense." Lieutenant 1st class P. van Lelyveldt stated: "The flotilla vessels are bad sea ships. They are too small, not suitable for service in the colonies, and lack proper lodgings for the crew." By giving a very positive comment about the class Captain-lieutenant J. Andrea was an exception. He stated that for certain purposes he thought the Haarlemmermeer class the best type of ship to send to the East Indies. He also stated that he thought them very useful there because they could sail up the many rivers, the Haarlemmermeer having sailed 80 miles up the Siak River on Sumatra. [16]
The summary of the 1862 investigation accidentally mentions the worst consequence of the design failure that the Haarlemmermeer class would later prove to be. Due to the attempt to combine too much functions on a small surface, the heat of the engines could not properly escape the ship. It points to insufficient ventilation, a major cause of dry rot.
By constructing the screw steamships 4th class, also designated as steam flotilla vessels, the designers tried to satisfy three demands. One wanted the vessels to be able to assist in the national defense by serving on our rivers, to be able to cross the ocean, and to serve in the East Indies. The consequence, in the opinion of almost all, is that these ships are not satisfactory in any respect. They have too much draught, are hindered by too heavy sails and rigging, and do not have enough space to lodge the crew. The lodgings of the crew are way too hot, and in the Indies the heat is almost unbearable. There were reports of the temperatures in the engine room reaching 150-180 degrees Fahrenheit (65-82 degrees Celsius) and of stokers fainting on the job. Misplaced economy seems to have had the usual consequences in this respect. [17]
Susceptibility to dry rot
The 1862 investigation of the navy was held when the class had been in the water for only 1–2 years. At that moment the most serious problem of the class was not yet known. By 1866 five of the nine ships in the class were no longer in service, all of them unfit after only a few years in the Dutch East Indies. A sixth ship, the Stavoren followed in 1868. That year she became a hydrographic vessel after less than four years of regular service in the Dutch East Indies. A seventh ship, the Dommel was probably already rotten in 1867, after service in the West Indies. Only two ships seemed an exception: The Amstel would become an old ship, even after serving a few years in the West Indies. The Haarlemmermeer would see extensive service in the East Indies, it was still short, but she survived significantly longer than the others.
The problem that brought these ships to an early end was dry rot, now called brown rot, a fungus that causes wood to decay. If found in oak wood the Dutch called it 'Vuur' and contaminated wood 'vervuurd'. In 1865 accidental repairs found the Apeldoorn to be so contaminated by dry rot that she could not be repaired. [18] The Linge was sold on account of dry rot in 1867. [19] The same was true for the Dommel in 1871. [20] In general all steam vessels generated heat on the inside of the ship, and were therefore more susceptible to dry rot than sailing ships, especially in the tropics. At the time it was well known that seasoning the wood before use and ventilation of the ship were the only effective means to prevent dry rot. As stated above, the design of the Haarlemmermeer did not allow sufficient ventilation.
The other known cause of dry rot was using unseasoned wood. Wood could be seasoned by storing it for some time before use, or by lengthening the construction time of ships, causing the wood to season while the ship was on the slipway. Already in 1860 the minister of the navy was warned that the class had been built too quickly. During the discussion about the law for the 1861 navy budget on 8 December 1860, the famous liberal M.P. Pieter Blussé van Oud-Alblas, a major shipping line owner from Dordrecht, made the following remarks:
I read on the bottom of page 2: Especially for steamships, which are exposed to varying degrees of temperatures, dampness and drought, and of which the timber is exposed to dry rot far more than that of sailing ships, it is important not to hasten construction more than necessary. They are to remain on the slipway for some time in order to prevent untimely decay. In order to do this without delaying construction more than necessary, one had to utilize all available slipways. On the slipway the frame of the ship would first be built. Later the ship would be rounded off and finished... Then at the bottom of page 3 I read: The advantage gained by leaving these (small) ships on the slipway for some time, while using the amount of wood only suitable for small vessels, prompted a decision to slowly built three more steam flotilla vessels at the Rijkswerf in Amsterdam, and two at the Rijkswerf Vlissingen.
(Blussé van Oud-Alblas summarizes): If this is useful for ships built at a Rijkswerf, it is also useful for ships built at a commercial shipyard. In the plans (for the ships built at commercial shipyards) this principle has been neglected, because these plans all order a very speedy delivery of these ships, so they cannot spend much time on the slipway. Therefore it's likely that these ships will speedily get affected by dry rot.
A few days later Blussé van Oud-Alblas continued: With respect to what I said about building the steam flotilla vessels the minister noted the moment when the vessels were tendered. He therefore admits that the time allowed for construction deviated from what he himself gave as a guideline for constructing ships on state shipyards. I have to note that while the tender was made, there might have been international tensions that caused hastened construction. However, since the tender these have disappeared, and yet construction has proceeded at the same hastened pace. Even in this year (1860) one has continued to finish the ships in a way too short timeframe. I fear that the consequence will be that these will not be as durable as others. Above all I fear that this will again be used as a reason not to build state ships on commercial shipyards. Therefore I want to annul this reason just now.
The minister of the navy Lotsy replied as follows: The remark that a too short time frame was allowed for the construction of the steam flotilla vessels, I can only answer in one way. It happened in the summer of last year (1859). At that moment even those that did not appreciate the international situation as very threatening were convinced of the necessity to improve the national defense as soon as possible.
Royal Netherlands Navy 
