DOCSLIB.ORG

Peters on (Fast) Powerboats

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Peters on (Fast) Powerboats Peters On (Fast) Powerboats The author’s eponymous Florida-based yacht design firm has developed some of the most successful high-performance production and custom powerboats in the world, across a broad range of categories: flats skiffs, sportfishermen, motoryachts, and offshore raceboats. Here, in Part 1, he presents his office’s consistent approach to the design process. by Michael Peters In the 18 years that Professional BoatBuilder has been producing, or Artwork courtesy of MPYD co-producing, the IBEX trade show, we have rarely repeated a seminar topic, even though the seminar program has offered upward of five dozen sessions per show. One notable exception was Michael Peters’s IBEX ’02 presentation titled “High-Speed Boat Design.” Audience response was so enthusiastic, we asked Peters to present it again, which he finally agreed to do…at IBEX ’08. But he refused to simply reprise his ’02 talk, because technology had evolved, and so had Peters. Having designed several of the fastest powerboats on the planet, he decided to back off from that scary end of the spectrum. What follows is Peters’s IBEX presentation in Miami Beach in 2008, adapted for print publication—Ed. hat exactly is high speed ? The reason I’m showing you this W In 1973, I spent the day wet- comparison is because I think our sanding the bottom of a sloop, get- idea of high speed is ill-defined. Take, ting the boat ready for a race the for example, a 34' [10.4m] Contender next day with a builder I was then outboard-powered center-console that working with. I came home and told does 50 knots. We’d probably all agree my dad what I’d been doing, and he 50 knots is a fast boat; note how the just laughed at me. “That’s absolutely Contender compares to the Reynolds ridiculous—wet-sanding the bottom Number of an F-16 fighter jet. Now, of a boat to make it go faster. You take our firm’s fastest design—a know, Michael, in aeronautics we Tencara raceboat fitted with turbine don’t even start worrying about rivets engines—and it has essentially the until about 250 knots.” same Reynolds Number as the U.S. My dad, being a mechanical engi- government’s SR-71 high-altitude, neer and having worked in the high-speed [2,000+ knots], long-range wind tunnel for NACA—the National reconnaissance plane. Advisory Committee for Aeronautics— So my question is: What is a high- during World War II, calculated the speed boat? Where do you think Reynolds Number for the sailboat to the line is when people start talking see if it made any sense to wet-sand about high speed ? Fifty miles per hour it [Figure 1]. The first thing he found [80.5 kmh]? Well, at my office—which was that the Reynolds Number of a I know is different from the way sailboat at racing speed of 8 knots some other design offices work—we compared favorably with a P-51 compare speed to the length of the Mustang single-seat fighter, one of boat. We take the waterline length, the war’s fastest prop-driven planes. as you would for a conventional sail- He also discovered that the surface boat, and view the waterline in terms smoothness of the bottom made a dif- of percentages. With that, we can ference almost as soon as the sailboat judge all boats, from large to small, in started moving. some sort of nondimensional way. 38 Professional BoatBuilder Slide 2 Figure 1. Reynolds Number 3 ρ x V x L Re = µ This equation non-dimensionalizes vessel speed and length by accounting for fluid properties: density (ρ) and dynamic viscosity (µ) Slide 2 Slide 6 Reynolds Number Figure 2. Speed/Length Ratio ρ x V x L V (knots) Re= S/L = µ L (ft) 4 High speed: S/L > 5.0 Non-dimensionalizes vessel speed and length by accounting for fluid properties: density (ρ) and dynamic viscosity (µ) If you accept Renato “Sonny” Levi’s definition of high speed, it would be a speed/length ratio of 5 and greater [2]. For the purposes of today’s talk, I’m using 5—though six years ago, at that IBEX, I said 4. Since then, I Two highly successful, and influential, large yachts—not designed by Peters—that ran across someone else’s definition meet the marine industry’s generally accepted definition of fast: the Mulder-designed of high speed, which loosely agreed 120'/36.6m Moonraker (top), and the Blount-designed 220'/67m Destriero. with mine, and I decided to change to Moonraker’s top speed is 67 knots; Destriero’s, 60. For a detailed account of the the higher number. latter’s design development, see Professional BoatBuilder No. 109, page 100. Okay: Take the waterline length, take the square root of it, and you can calculate the speed/length ratio. bottom the way Moonraker is up on For a 100' [30.5m] waterline, the hers. This observed phenomenon is square root is 10; if you’re doing 30 purely indicative of relative size. knots, the S/L ratio is 3. In theory, speed varies as the cube Let’s look at a boat most people of horsepower divided by weight. If would consider fast: the Mulder- all factors are equal, eight times the designed 120' [36.6m] Moonraker [3], power is needed to double the speed. capable of 67 knots. Her S/L ratio In reality, things don’t stay the same; is almost 7. Or consider the Blount- we can do much better. As we’ll see designed 220' [67m] transatlantic in Part 2, a modern racing catama- record-holder Destriero [4]; her S/L ran can achieve a speed equal to the ratio is 4. Destriero does 60 knots; square of horsepower divided by I think we’d all agree that’s pretty weight. fast. But if you put Destriero on a There are several ways to calculate graph and actually chart out what S/L the speed of a planing boat. Crouch’s ratio you’re sitting in, you find that formula is commonly used by many Destriero does not fit our definition of in the industry as a shorthand method high speed [8]. for predicting speed [5]. Sonny Levi’s Also, notice the way Destriero is formula is what I started with, in the running compared to Moonraker. 1970s [6]. But the formula that we Moonraker has much more boat employ in our office today is one out of the water than Destriero has. taught to me by Eduardo Reyes, a Remember, there are different speed Cuban who escaped the island when zones: an S/L ratio of 5 is something Fidel Castro took over [7]. of an arbitrary line, and if you lower Actually, what we find in our practice the ratio to 4, Destriero is clearly is that any one of these formulas will inside it. My point is, because of her work; it’s a matter of becoming fully size, because of her length, relative to familiar with the one you’re using. that length, Destriero is planing, even They’re all fairly simple. But in all though she’s not really up on her three formulas, understanding what august/sePtemBer 2010 39 Slide 2 Slide 10 Reynolds Number Figure 5. Performance Prediction Figure 8. ρ x V x L Crouch’s Formula: Re= 75 µ C 70 mph = Moonraker 65 S/L = 5.0 Non-dimensionalizes vessel ∆ HP 60 speed and length by accounting High Speed Destriero 55 for fluid properties: density (ρ) Where: and dynamic viscosity (µ) ∆ = Displacement of vessel (lbs) 50 Full Planing C = Constant based on 45 S/L = 3.0 40 Slide 2 boat type (180–200) Slide 11 35 30 Reynolds Number Figure 6. Performance Prediction Transition Region 25 S/L = 1.4 Sonny Levi’s Formula: 20 ρ x V x L Speed (knots) Vessel Re= µ 15 mph = K x SHP 10 Displacement Non-dimensionalizes vessel ∆ 5 speed and length by accounting Where: 0 for fluid properties: density (ρ) ∆ = Displacement of vessel (LT) 25 50 75 100 125 150 175 200 225 250 and dynamic viscosity (µ) K = 3.9–4 for single shaft 3.5–3.6 for twin shaft Waterline Length (feet) 3.2–3.3 for three shafts Slide 2 3.0–3.1 for four shafts A graphic representation of performance designations based on vessel speed-to- Slide 12 length ratio. Note the relative positions of Moonraker and Destriero in this context. Reynolds Number Figure 7. Performance Prediction where you want and you’ve got your around, Where do you think this boat ρ x V x L engines where you want and all the ought to balance? One guy will say, I Re= Eduardo Reyes’s Formula: µ rest. You end up with a longitudi- think it ought to balance around 6.2. HP x 46.4 nal center of gravity, and you say, And another one says, I think our V (knots) = K Okay, now I’m gonna design my boat drawing puts it at 6.5. Non-dimensionalizes vessel ∆ around this. Well, what if that LCG It doesn’t matter what length boat speed and length by accounting Where: is just plain wrong to begin with? we’re talking about. What matters is C for fluid properties: density (ρ) Because the center of gravity varies the speed-to-length ratio. The physics and dynamic viscosity (µ) ∆ = Displacement of vessel (LT) ∆ K = Constant based on with the speed.
Load more

Recommended publications
  • On the Calculation of Propulsive Characteristics of a Bulk-Carrier Moving in Head Seas
    Journal of Marine Science and Engineering Article On the Calculation of Propulsive Characteristics of a Bulk-Carrier Moving in Head Seas S. Polyzos and G. Tzabiras * School of Naval Architecture & Marine Engineering, National Technical University of Athens, 15780 Athens, Greece; [email protected] * Correspondence: tzab@fluid.mech.ntua.gr; Tel.: +30-210-772-1107 Received: 14 September 2020; Accepted: 8 October 2020; Published: 9 October 2020 Abstract: The present work describes a simplified Computational Fluid Dynamics (CFD) approach in order to calculate the propulsive performance of a ship moving at steady forward speed in head seas. The proposed method combines experimental data concerning the added resistance at model scale with full scale Reynolds Averages Navier–Stokes (RANS) computations, using an in-house solver. In order to simulate the propeller performance, the actuator disk concept is employed. The propeller thrust is calculated in the time domain, assuming that the total resistance of the ship is the sum of the still water resistance and the added component derived by the towing tank data. The unsteady RANS equations are solved until self-propulsion is achieved at a given time step. Then, the computed values of both the flow rate through the propeller and the thrust are stored and, after the end of the examined time period, they are processed for calculating the variation of Shaft Horsepower (SHP) and RPM of the ship’s engine. The method is applied for a bulk carrier which has been tested in model scale at the towing tank of the Laboratory for Ship and Marine Hydrodynamics (LSMH) of the National Technical University of Athens (NTUA).
    [Show full text]
  • Load Line Length - Policy Clarification - Hullform Cut- Outs, Extensions and Steps
    Maritime and Coastguard Agency LogMARINE GUIDANCE NOTE MGN 645 (M) Load Line Length - Policy Clarification - Hullform Cut- Outs, Extensions and Steps Notice to all Owners and builders of Small Commercial Vessels, Shipowners, Designers, Masters, Assigning Authorities and Surveyors This notice should be read with.. The Merchant Shipping (Load Line) Regulations 1998 - SI 1998 No.2241, as amended The Safety of Small Commercial Motor Vessels - A Code of Practice (Yellow Code) The Safety of Small Commercial Sailing Vessels - A Code of Practice (Blue Code) The Safety of Small Workboats and Pilot Boats - A Code of Practice (Brown Code) The Code of Practice for the Safety of Small Vessels in Commercial Use for Sport or Pleasure Operating from a Nominated Departure Point (Red Code) MGN280: Small Vessels in Commercial Use for Sport or Pleasure, Workboats and Pilot Boats - Alternative Construction Standards Summary This Note clarifies the UK policy when determining Load Line Length on vessel hullforms featuring cut-outs, removable end sections, or bathing platforms. 1. Foreword 1.1 This MGN relates to vessels with under 24m in Load Line Length, where the keel of which was laid on or after the date these regulations were implemented and were measured in accordance with the regulations in force at that time. 2. Introduction 2.1 Load Line Length (L) is used as a breakpoint for determining whether a vessel should comply with the requirements for either small vessels or large vessels. Identifying this size breakpoint is particularly important when the determination of the length of the vessel on the 85% waterline or identification of the point of least moulded depth is not straight forward due to particular design arrangements.
    [Show full text]
  • 2. Bulbous Bow Design and Construction Historical Origin
    2. Bulbous Bow Design and Construction Ship Design I Manuel Ventura MSc in Marine Engineering and Naval Architecture Historical Origin • The bulbous bow was originated in the bow ram (esporão), a structure of military nature utilized in war ships on the end of the XIXth century, beginning of the XXth century. Bulbous Bow 2 1 Bulbous Bow • The bulbous bow was allegedly invented in the David Taylor Model Basin (DTMB) in the EUA Bulbous Bow 3 Introduction of the Bulbous Bows • The first bulbous bows appeared in the 1920s with the “Bremen” and the “Europa”, two German passenger ships built to operate in the North Atlantic. The “Bremen”, built in 1929, won the Blue Riband of the crossing of the Atlantic with the speed of 27.9 knots. • Other smaller passenger ships, such as the American “President Hoover” and “President Coolidge” of 1931, started to appear with bulbous bows although they were still considered as experimental, by ship owners and shipyards. • In 1935, the “Normandie”, built with a bulbous bow, attained the 30 knots. Bulbous Bow 4 2 Bulbous Bow in Japan • Some navy ships from WWII such as the cruiser “Yamato” (1940) used already bulbous bows • The systematic research started on the late 1950s • The “Yamashiro Maru”, built on 1963 at the Mitsubishi shipyard in Japan, was the first ship equipped with a bulbous bow. • The ship attained the speed of 20’ with 13.500 hp while similar ships needed 17.500 hp to reach the same speed. Bulbous Bow 5 Evolution of the Bulb • Diagram that relates the evolution of the application of bulbs as
    [Show full text]
  • Ship Design Decision Support for a Carbon Dioxide Constrained Future
    Ship Design Decision Support for a Carbon Dioxide Constrained Future John Nicholas Calleya A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy of University College London. Department of Mechanical Engineering University College London 2014 2 I, John Calleya confirm that that the work submitted in this Thesis is my own. Where information has been derived from other sources I confirm that this has been indicated in the Thesis. Abstract The future may herald higher energy prices and greater regulation of shipping’s greenhouse gas emissions. Especially with the introduction of the Energy Efficiency Design Index (EEDI), tools are needed to assist engineers in selecting the best solutions to meet evolving requirements for reducing fuel consumption and associated carbon dioxide (CO2) emissions. To that end, a concept design tool, the Ship Impact Model (SIM), for quickly calculating the technical performance of a ship with different CO2 reducing technologies at an early design stage has been developed. The basis for this model is the calculation of changes from a known baseline ship and the consideration of profitability as the main incentive for ship owners or operators to invest in technologies that reduce CO2 emissions. The model and its interface with different technologies (including different energy sources) is flexible to different technology options; having been developed alongside technology reviews and design studies carried out by the partners in two different projects, “Low Carbon Shipping - A Systems Approach” majority funded by the RCUK energy programme and “Energy Technology Institute Heavy Duty Vehicle Efficiency - Marine” led by Rolls-Royce.
    [Show full text]
  • Nautical Terms English Translated to Creole
    Nautical Terms Translated English to Creole A Abaft Aryè Abeam Atraver Aboard Abò Adrift En derive Advection fog Bouya advection Aft Arrière Aground A tè Ahead De van Aids to navigation (ATON) Ed pou navigasyon Air draft Vent en lè a Air intake Rale lè a Air exhaust Sorti lè a Allision Abodaj Aloft Altitid Alternator Altènatè Amidship Mitan bato an Anchor Lank Anchorage area Zòn ancrage nan Anchor’s aweigh Derape lank nan Anchor bend (fisherman’s bend) Un tour mort et deux demi-cle (mare cord pecher poisson utilize) Anchor light Limyè lank Anchor rode Lank wouj Anchor well Lank byen Aneroid barometer Bawomèt aneroid Apparent wind Van aparan Astern Aryèr Athwartship A travè bato Attitude Atitid Automatic pilot Pilot otomatik Auxiliary engine Motè oksilyè B Back and drill Utilize pousse lateral helice lan pou manevrer bato an Backing plate Kontre plak Backing spring (line) Line pou remorkage Backstay Pataras Ballast Lèst Bar Barre Barge Peniche Barograph Barograf Barometer Baromèt Bathing ladder Echèl pou bin yin Batten Latte Batten down! Koinsez pano yo Batten pocket Poche ou gousset pou metez latte yo ladan Battery Batri Battery charger Chag batri Beacon Balis Beam Poto Beam reach Laje poto Bearing Relevman Bear off Pati lot bo Beating Remonte vent Beaufort wind scale Echel vent Beaufort Before the wind Avan vent Bell buoy Bouye ak kloche Below Anba Berth Plas a kouche Belt Kouroi Bilge Cale (kote tout dlo/liqid ranmase en ba bato an) Bilge alarm system System alarm pou cale Bilge drain Evakuation pou cale Bilge pump Pomp pou cale Bimini
    [Show full text]
  • With Addendum) St
    Annex A Inspection report (with addendum) St. Mary’s House Commercial Road Penryn, Falmouth Cornwall, TR10 8AG Marine Surveyors and Consulting Engineers Tel: +44 (0) 1326 375500 Fax: +44 (0) 1326 374777 http://www.rpearce.co.uk 23rd March 2012 THIS IS TO CERTIFY that at the request of the Marine Accident Investigation Branch (MAIB), Mountbatten House Grosvenor Square, Southampton, SO15 2JU, a survey was held on the wooden single screw fishing vessel “HEATHER ANNE” of the port of Fowey, FY126, GT 11.67, whilst shored up on the Queens Wharf in Falmouth Docks, Cornwall, for the purpose of assisting with an investigation following the vessels sinking on the 20th December 2011. BACKGROUND The vessel had been fishing for pilchards and was returning to port when at about 2213 hours on the 20th December 2011 she capsized and sank in Gerrans Bay. The incident was seen by the crew of the fishing vessel LAUREN KATE who raised the alarm and recovered the two man crew from the water. Sadly one of the crewmen died. VISITS TO VESSEL The undersigned visited the vessel on the following dates:- 27th February 2012 – Meet with representatives of the MAIB to discuss the survey of the vessel. 7th March 2012 – Attend the vessel in the company of a representative of the MAIB to conduct a survey in accordance with the instructions below. 8th March 2012 – Attend the vessel to obtain additional data for this report. 14th March 2012 – Attend the vessel in the company of the Salver to discuss sealing the hull in order to re- launch the vessel for a stability test.
    [Show full text]
  • 1 Seagoing Ships 8 Fishing Vessels Edition 2007
    Rules for Classification and Construction I Ship Technology 1 Seagoing Ships 8 Fishing Vessels Edition 2007 The following Rules come into force on October 1st , 2007 Germanischer Lloyd Aktiengesellschaft Head Office Vorsetzen 35, 20459 Hamburg Phone: +49 40 36149-0 Fax: +49 40 36149-200 [email protected] www.gl-group.com "General Terms and Conditions" of the respective latest edition will be applicable (see Rules for Classification and Construction, I - Ship Technology, Part 0 - Classification and Surveys). Reproduction by printing or photostatic means is only permissible with the consent of Germanischer Lloyd Aktiengesellschaft. Published by: Germanischer Lloyd Aktiengesellschaft, Hamburg Printed by: Gebrüder Braasch GmbH, Hamburg I - Part 1 Table of Contents Chapter 8 GL 2007 Page 3 Table of Contents Section 1 General A. Application ................................................................................................................................. 1- 1 B. Class Notations ........................................................................................................................... 1- 1 C. Ambient Conditions ................................................................................................................... 1- 2 D. Definitions .................................................................................................................................. 1- 2 E. Documents for Approval ...........................................................................................................
    [Show full text]
  • (CWP) Handbook of Fishery Statistical Standards Annex LIII
    Coordinating Working Party on Fishery Statistics (CWP) Handbook of Fishery Statistical Standards Annex LIII: Length of Fishery Vessels (Approved at the 11th Session of the CWP, 1982) Length overall (o/l): The most frequently used and preferred measure of the length of a fishing vessel is the length overall. This refers to the maximum length of a vessel from the two points on the hull most distant from each other, measured perpendicular to the waterline Other measures of the length of vessels are: Waterline length (w/l) refers to the length of the designed waterline of the vessel from the stern to the stern. This measure is used in determining certain properties of a vessel for example, the water displacement; Length between perpendiculars (p/p) refers to the length of a vessel along the waterline from the forward surface of the stern, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. This is believed to give a reasonable idea of the vessel’s carrying capacity, as it excludes the small, often unusable volume contained in her overhanging ends. On some types of vessels this is, for all practical purposes, a waterline measurement. In a vessel with raked stern, naturally this length <change as the draught of the ship changes, therefore it is measured from the defined loaded condition. p/p Length between perpendiculars w/l Waterline length o/a Length overall b Breadth f Freeboard d Draught Coordinating Working Party on Fishery Statistics (CWP) Handbook of Fishery Statistical Standards Vessel size (length overall in Code meters) Lower limit Upper limit 210 0 5.9 221 6 11.9 222 12 17.9 223 18 23.9 224 24 29.9 225 30 35.9 230 36 44.9 240 45 59.9 250 60 74.9 260 75 99.9 270 100 and over Annex LVII: Vessel size (Approved by CWP-11, 1982) .
    [Show full text]
  • Impact of Hard Fouling on the Ship Performance of Different Ship Forms
    Journal of Marine Science and Engineering Article Impact of Hard Fouling on the Ship Performance of Different Ship Forms Andrea Farkas 1, Nastia Degiuli 1,*, Ivana Marti´c 1 and Roko Dejhalla 2 1 Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Luˇci´ca5, 10000 Zagreb, Croatia; [email protected] (A.F.); [email protected] (I.M.) 2 Faculty of Engineering, University of Rijeka, Vukovarska ulica 58, 51000 Rijeka, Croatia; [email protected] * Correspondence: [email protected]; Tel.: +38-516-168-269 Received: 3 September 2020; Accepted: 24 September 2020; Published: 26 September 2020 Abstract: The successful optimization of a maintenance schedule, which represents one of the most important operational measures for the reduction of fuel consumption and greenhouse gas emission, relies on accurate prediction of the impact of cleaning on the ship performance. The impact of cleaning can be considered through the impact of biofouling on ship performance, which is defined with delivered power and propeller rotation rate. In this study, the impact of hard fouling on the ship performance is investigated for three ship types, keeping in mind that ship performance can significantly vary amongst different ship types. Computational fluid dynamics (CFD) simulations are carried out for several fouling conditions by employing the roughness function for hard fouling into the wall function of CFD solver. Firstly, the verification study is performed, and the numerical uncertainty is quantified. The validation study is performed for smooth surface condition and, thereafter, the impact of hard fouling on resistance, open water and propulsion characteristics is assessed.
    [Show full text]
  • Waterline Length: 32’-0” Warmer Weather
    POSSIBLE USERS TOUR OPERATORS – Capable of speeds up to 55 mph, hotels, cruise lines, resorts, and tour companies can offer unique trips to enhance the experience of their guests. PUBLIC TRANSPORTATION – With its capacity to carry 47 passengers at 40 mph cruising speeds, in water as shallow as 12 inches, along with its low maintenance aluminum hull and Hamilton jet pumps, it offers an attractive alternative to buses and trains along inland waterways. MINING AND EXPLORATION – in severe climate conditions, this rugged vessel can deliver people and supplies in an enclosed, heated environment. “Happy Hour” is the second tour boat Killgore Adventures has purchased and together with “Moonshine”, Killgore’s 28’ boat, passengers will have the opportunity to safely see Hell’s Canyon, the deepest gorge in North America and its spectacular whitewater. The U.S.C.G. certified boat has a combination of booth and Type of vessel: Passenger and Freight bus style seating with the center bus seating being removable to Owner: Killgore Adventures allow for raft party jet backs. Driven aft, the boat’s captain can Operator: Kurt Killgore not only navigate the river but also view passengers reducing Home Port: White Bird, Idaho the total amount of required deckhands. Designer: Darell Bentz Passengers can be boarded over the bow using the fold down bow ladder or through the aft gates to either side. Freight Builder: Bentz Boats, LLC and gear can also be loaded through the larger center door Construction Material: Aluminum opening forward or through the expansive side openings. Side Length: 36’-0” curtains are available for cooler days but are removed during Waterline Length: 32’-0” warmer weather.
    [Show full text]
  • Knowing Your Boat Means Knowing Its Wake
    Knowing your boat means knowing its wake This is an illustrated guide to wave wake that expands upon the basics outlined in the low wake guide “Wake up? Slow Down”, which is available at: http://dpipwe.tas.gov.au/Documents/Guide-to-Low-Wave-Wake-Boating.pdf We all know ‘stow it – don’t throw it’ but what about what Bryce Courtenay’s Yowie said to the Dirty Rotten Rubbish Grumpkin: “not thinking is the same as not caring”? Here are 18 illustrations to help boaters think about their wake and its potential erosive impacts in sheltered, restricted or shallow waters. Environmental effects of wave wake In the open sea wave wake is likely to have little environmental effect since the waves are small compared to those that might occur naturally. It’s a very different matter in sheltered waters like riverine estuaries. The soft banks and beds of many Tasmanian waterways are vulnerable to damage from boat wake and prop wash. Typical easily-affected landforms include estuaries, inlets, lakes and lagoons; places where natural wave energy tends to be low. Banks of peat or mud, shallow lagoons or lakes with muddy beds and sandy deposits in upper estuaries are all areas of risk. Wake striking the banks can cause rapid and severe erosion, exposing the roots of vegetation and causing the banks to collapse. Wake impact and prop wash can also churn up fine bed sediments – the impact on bed and banks degrades the aquatic environment for plants and animals. In some popular boating and cruising areas, the effects of wake damage have been severe – for example, on the lower Gordon River, long stretches of bank have been washed away, with mature Huon pines and myrtles toppling into the river.
    [Show full text]
  • Wetted Surface Area of Recreational Boats
    National Institute forPublic Health and the Environment Ministryof Health, Welfare and Sport Wetted surface area of recreational boats RIVM Report 2017-0116 J. Bakker | P.L.A. van Vlaardingen Wetted surface area of recreational boats RIVM Report 2017-0116 RIVM Report 2017-0116 Colophon © RIVM 2017 Parts of this publication may be reproduced, provided acknowledgement is given to: National Institute for Public Health and the Environment, along with the title and year of publication. DOI 10.21945/RIVM-2017-0116 J. Bakker (author), RIVM P.L.A. van Vlaardingen (author), RIVM Contact: Joost Bakker Centrum voor Veiligheid van Stoffen en Producten Centre for Safety of Substances and Products [email protected] This investigation was conducted by order and for the account of Ministry of Infrastructure and Water Management, within the framework of the project Policy Advice and Methodology for Biocides and Plant Protection Products This is a publication of: National Institute for Public Health and the Environment P.O. Box 1 | 3720 BA Bilthoven The Netherlands www.rivm.nl/en Page 2 of 64 RIVM Report 2017-0116 Synopsis Wetted surface area of recreational craft The wetted surface area of recreational craft is often treated with special paint that prevents growth of algae and other organisms. The active substances in this paint (antifouling) are also emitted into the water. The extent of this emission is among others determined by the treated surface area. The RIVM has developed a method to calculate the wetted surface area of recreational craft based on boat length. This is essential to assess the environmental effects associated with these emissions.
    [Show full text]