If water is allowed to build up behind the wall, this increases lateral pressure acting on the wall and unless properly considered in the design, this could lead to failure. Weep holes can alleviate this problem by ensuring that water drains from the retained soil. The effectiveness of weep holes can be improved by incorporating a zone of drainage aggregate behind the wall, continuous between weep holes. The advantages of weep holes Sharpe’s London Journal of Entertainment and Instruction (1850) The little hero of Haarlem. Volume 12. A. Hall, Virtue & Co., London, pp 8–9 Weep holes can be formed in a retaining wall during construction very simply and at little cost. The method of forming the weep hole will depend to some extent on the type of retaining wall. Open joint method Is there any musty/moldy smell inside? This could indicate leakage, prior water damage or simply neglect.

Who will use the boat? Just family or will you invite friends? This may have a bearing on the size. Principal Water Authority of Rijnland (2017) https://www.rijnland.net/over-rijnland/erfgoed/artikelen-uitgelicht/hans-brinker-en-rijnland. Consulted July 2017 Gehrts M, Gehrts G, Jacobi J (1890) Hans Brinker oder Die silbernen Schlittschuhe. Verlag Thienemann, Stuttgart (in German)

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Sargent’s school monthly, for home and school use (1858) In: Sargent E (ed) The boy at the Dike. Volume 1, Nos. I–XII. Philips, Sampson & Co., Boston, p 222 Figure 4 - Clay pipe was used to form weep holes, with stone cut to fit around the pipe, in this Victorian era retaining wall Drill method The two most widely-used sayings about boats are that they are “holes in the water, into which you throw money” and “the happiest day of a boat owner’s life is the day they buy the boat and the day they sell it.” Although many people believe these axioms are true, they don’t necessarily have to be if you approach boat ownership with an understanding of what is involved. Look Before You Leap Hartmann I, Radig J (2013) Documentary on the Hero of Haarlem. Duration 10:36 minutes. Youtube: uploaded at 27 March 2013. Hogeshool INHOLLAND, Haarlem (in Dutch)

Over time, weep holes can become clogged with vegetation or algae growth, reducing their effectiveness. If the weep holes outfall above ground level, they can be unsightly, particularly after many years of water staining or algae growth on the wall face. The effectiveness of weep holes is limited when the retained soil is a clay, particularly if no drainage zone is incorporated behind the wall face. What are the different types of weep holes?Wikipedia English version (2017) https://en.wikipedia.org/wiki/Hans_Brinker,_or_The_Silver_Skates. Consulted July 2017