Marine Cafe Blog.....

Might want to check out a way cool blog at http://www.marine-cafe.com/

Bertram Fuel Tanks

Tests of fiberglass fuel tanks from a 1967 and 1970 Bertram:

Testing Summary:

To date, the testing done by IMS, LLC indicates that the two fuel tank samples have undergone some aggressive degradation (40% of their strength) from gas - ethanol fuel blends. The bottoms of both tanks have lost more strength than the tops. The older tank (1967) was laminated to a much higher level of quality in terms of entrapped air and fiber roll out. The mode of property reduction in the newer tank (1970) appears to be both resin softening and loss of adhesion between fiber and resin. This is evidenced by a moderate loss in both strength and stiffness. The older tank has lost nearly a similar amount of strength but has retained all its original stiffness. This indicates some resin degradation has occurred but no loss of the fiber/resin interface’s integrity has occurred.

Should check for presence of ethanol using the following methods -

To check for ethanol in gasoline - use two bottles, with calibrations in ounces.
In one bottle put ten ounces of gas from the suspect tank, in the second bottle - put two ounces of tap water.

Pour the water in to the bottle with the gas, cap off and shake.

Let set and the water will settle to the bottom and if ethanol is present it will absorb the water and the fill line will change from twelve ounces to something else. If this is the case - then the tank should be viewed as suspect - replacing tanks can be a trick.

Poultice Corrosion

This entire corrosion thing is one of the many dark arts of boat maintenance faced by mariners today. Nothing really happens overnight – and in the case of corrosion related wastage of metals – the deterioration process is usually slow with ample but subtle tell tales along the way to give the alert mariner time to take corrective actions. One of the most insidious forms of corrosion is found as small patches or blooms of white powder-like deposits on aluminum. Poultice corrosion can happen on unprotected aluminum or under bubbling paint. In either case – the amount of wastage can be severe if not discovered and properly treated. Before looking at the cure – let’s discuss the cause.

Here’s a classic example of poultice corrosion – a bare aluminum window frame on a Hatteras which has been damaged by corrosion. Over a period of time, water trapped by debris and dirt against the aluminum frame formed an acidity material call aluminum hydroxide which has perforated the frame leaving white deposits scattered across the sill. Poultice or under deposit attack corrosion may occur when bare, unprotected aluminum surfaces are covered by absorbent materials, dirt, and debris trapping moisture against the unprotected metal surface. In this instance, corrosion attack can continue even when the other surfaces are dry due to the retention of moisture in the poultice. The corrosion mechanism is similar to crevice corrosion in that the covering materials or deposits act to limit the migration of oxygen to the covered area. This leads to acidic shifts in pH, concentration of Clˉ ions in the shielded area, and a more active corrosion potential under the deposit. Negatively charged chloride ions tend to migrate under the deposit to balance the positively charged aluminum ions produced there. The high concentration of chloride ions causes the area under the deposit to become more acidic compared to the bulk solution, further enhancing the corrosion under the deposit with a white, poultice-like material produced (aluminum hydroxide).

Corrosion attack on aluminum surfaces is usually quite obvious, since the products of corrosion are white and generally more voluminous than the original base metal. Even in its early stage, aluminum corrosion is evident as general etching, pitting, or roughness of the surface. Aluminum alloys commonly form a layer of smooth surface oxidation (0.001” to 0.025 thick). This is not considered detrimental as it provides a barrier against corrosion. But when this protective layer is removed – damage can and will happen.

Another real site for problematic poultice corrosion is aluminum fuel tanks. Don’t store cardboard boxes, equipment, or other items on top of tanks. Don’t use moisture wicking materials to cushion tanks against framing structures. ABYC recommends tankage to be installed in accordance with H-24 (gasoline fuel systems) which states that all non-integral tank supports, chocks, or hangers shall be separated from metallic tank surfaces by a non-metallic, non-moisture absorbent and non-abrasive material suitable for the purpose (e.g., neoprene, Teflon, and high density plastics) permanently bonded to the tank surface with impermeable, non-hydroscopic adhesive. Self-wicking material, such as carpet pile, shall not be in contact with a metallic tank.

Another common refuse for poultice corrosion attack is in the deck boxes of aluminum sport boats where stowed fishing gear, nets, towels, and life jacket can trap moisture against bare aluminum.

Poultice corrosion can also occur under chipped paint – the mechanism is the same – trapped moisture against unprotected aluminum. Look at paint bubbles – such as around beauty rings on portholes (don’t be confused by galvanic corrosion). Chipped paint or coatings will promote poultice corrosion – allowing moisture to be trapped against bare metal. The best form of prevention is to properly coat all bare metal surfaces. If not possible, bare aluminum must be kept clean and dry – free of wicking materials. Think about inside airplane wings – aluminium is always coated to prevent corrosion. Maintain regular cleaning and proper coating of all exposed surfaces to prevent corrosion.

Unprotected aluminium should be maintained within a pH range of 6 to 8 where the alloy is stable. In the event of poultice attack, a base solution should be applied to control acidic corrosion. Protective steps would include, but not limited to the use of Alodine®. This material is one step in a multi-stage protection scheme and does not provide sacrificial protection to aluminum alloys. Instead, it acts as a passivating inorganic thin coating over which a primer can be applied. In the same manner, a zinc chromate primer does not provide sacrificial protection but its corrosion inhibiting properties retard but does not prevent corrosion.

Corrosion....

Galvanic Corrosion Thoughts…To avoid or reduce wastage -

• Thoroughly and carefully coat or paint metals especially in galvanic cells.

• If a coating is used, then use it on the cathode (the metal which is not going to corrode) because coating the zinc anodes will reduce their surface area. Reduce the area of the cathode not the anode.

• If dissimilar metals are causing unwanted corrosion – then one or more of the following should be done –

• Electrically isolate dissimilar metals.

• Select metals that are close to each other on the galvanic series.

• Change the potential between metals (anodes – impressed current systems).

• Properly wire vessels to ABYC standards – no ground and neutral lines connected.

• Use galvanic isolator – transformer.

Anode Selection

• Zinc – Salt Water (make sure to use Military Spec M 18001J zinc anodes).

• Activated Aluminum – an alternative to zinc in sea or brackish waters. Both zinc and activated aluminum do not work well in fresh water unless cleaned monthly.

• Magnesium – Freshwater, potential excessive protection in seawater (short life).

Port Orchard Yacht Sales

It's a cold, dark, rainy day here in Western Washington - so there's no better place to hang out than Robert Heay's Port Orchard Yacht Sales. Robert has owned POYS for the past 27-years - combined with his 30+ years of sailing experience - makes this yacht brokerage one of the best on the west coast. Stop by and say hi to Rob, Trish (the Fab) and Ken. 360.876.4584.

Sail Rig Inspection....

Sail Rig inspection guidance from the USCG Sector Honolulu Inspection Note Number 13

- Weekly - all rigging hardware at deck level be thorough cleaned and rinsed.

- Monthly - a thorough inspection of all rigging equipment.

- Annual – a comprehensive (mast standing) inspection of mast and rigging system with rigging slacked off, turnbuckles opened and lubricated with rigging properly tension and re-tuned.

- Every six (6) years - mast removal and disassembly of all components for comprehensive inspection.

- Replacement of stainless fittings every five (5) to ten (10) years for vessels operating in the tropics.

- The USCG Sector Honolulu Inspection Note Number 13 refers to a six (6) year “cycle” – Replace wire every 6 years, terminal fittings every twelve (12) years, and chain plates every eighteen (18) years. This may be as a result of the “tropics” and the beating it gives to stainless steel rigging. Mariners have all seen rigs that are well over ten (10) years old that appear to be in serviceable condition. A conservative estimate may be to use the “six year cycle” for those vessels operating in the tropics. Then move to possibly an “eight year cycle for those operating on the “coasts”. With a “ten year cycle” for those vessels that are used in the northern climates.

-

Happy New Year....

Are You A Marine Surveyor ?

March 2011 Marine Survey Class

Introduction to the Art of Marine Survey -Yachts and Small Craft

7 to 11 March 2011 – 0830 to 1700

Nordby Conference Center – Fishermen’s Terminal

Seattle, Washington

Monday

- Welcome and course introduction

- Marine survey and the role of the marine surveyor

- Accreditation societies (SAMS, NAMS)

- Request for services

- Vessel types and descriptions

- Nature of observations and findings

- Use of USCG Navigation - Vessel Inspections Circulars (NVIC) as guidance in

marine survey work.

- Lunch (1200 – 1300)

- Tools used in marine survey work

- Galvanic Corrosion

- Wooden vessel construction, deficiencies, and inspection techniques –

Tuesday

- Recap of previous day

- Wooden vessel construction, deficiencies, and inspection techniques

- Wooden vessel fastenings and inspection techniques

- Observation and recommendations regarding refastening

- Fiberglass vessel construction, deficiencies, and inspection techniques

- Use of electronic moisture meters

- Lunch (1200 – 1300)

- Steel and aluminum vessel construction, deficiencies, and NDT inspection

- Electrical Systems

Wednesday

- Recap of previous day

- Vessel safety systems, lifesaving devices, and regulations

(USCG Auxiliary, Zenith Maritime).

- Sail rig inspection

- Lunch (1200 – 1300)

- Overview of damage surveys

- Marine machinery inspection

- Review of ABYC, NFPA, and CFR standards and recommended practices

- Commercial vessel inspection – passenger and fishing (flag administration

classification and certification schemes – regulations - USCG, DNV)

Thursday

- Recap of previous day

- Vessel stability observations – Capt. David Yell

- Survey reports – content and use of work product by clients, marine lenders,

insurance underwriters, and marine trade professional

- Lunch (1200 – 1300)

- Review of survey reports – nature of minimum content

- Value surveys (Fair Market Value – Best and Highest Use – Comparative Sales)

Friday

- Recap of previous day

- Boat yard – marina inspections

- Lunch (1200 – 1300)

- Preparation of group reports on findings

- Presentation of group reports

- Presentation of Certificates of Completion

Materials (supplied) –

- Student study guide – Zenith Maritime and guest speakers

- Surveying Fiberglass Sail Boats, Henry Mustin

- Federal Requirements for Recreational and Fishing Vessels - USCG

Recommended Reading –

- Surveying Small Craft, Ian Nicolson – Sheridan House

- Metal Corrosion in Boats, Nigel Warren – International Marine Publishing

- The Nature of Boats, David Gerr - International Marine Publishing

- Details of Classic Boat Construction, The Hull – Larry Pardey – Waterline Books

- ABYC – Standards and Recommended Practices for Yachts and Small Craft – American

Yacht and Boat Council

- National Fire Protection Association 10/302 – NFPA

- 33 CFR Subchapter S – Boating Safety (Parts 173 – 199), 46 CFR Subchapter C –

Uninspected Vessels (Parts 24 to 28), 46 CFR Subchapter T – Inspected Small Passenger

Vessels (Parts 175 to 185).

Classroom Location -

Nordby Conference Center, Fishermen’s Terminal – Seattle, Washington.

The Nordby Building (just east of the main terminal building – towards net sheds) – conference room is on north side of building (facing boat basin).

3919 18^th Ave West

Seattle, Washington 98119

Fuel Hoses.....

- Flexible fuel hose used in marine applications must meet the requirements of SAE J1527 and must be marked as such (ABYC H-24 and H-33). Flexible fuel hose for marine use is rated for specific applications using a letter – number combination. The United States Coast Guard (USCG) has designated four types of marine fuel hoses – viz., A1, A2, B1, and B2. The USCG requires fuel hose approved for marine applications to be marked “USCG Approved Type __” every twelve (12) inches – along with the date of manufacture (see photograph below of a section of USCG Approved A1 marine fuel hose which is marked fire and alcohol resistant). ABYC Sections H-24 and H-33 specifies fuel hose types and usage for gasoline and diesel fuel systems. Newer alcohol based fuels will cause older approved hoses to deteriorate and leak. Each flexible fuel hose end must be secured by a swaged sleeve, and sleeve – threaded insert, or a corrosion resistant hose clamp. Note – not all Type A hose is designed to be clamped.

Type A1 hose is for critical fuel delivery applications for both gasoline and diesel fuel products due to its good fire resistance and low permeation characteristics. 33 CFR 183 requires that A1 or A1-15 hose be used for inboard gasoline machinery fuel systems. ABYC H-33 recommends either A1 or A2 for diesel fuel applications within engine compartments. Type A1, A1-15, and A2 hose is required and or recommended for vent and fill applications. Type B1 and B2 fuel hose is also recommended for use as vent and fill hose outside the engine compartment where a break in fuel systems will not result in the discharge of not more than five (5) ounces of fuel in 2-1/2 minutes. All fuel delivery, fill, and vent hoses must be of proper specifications. The use of non-marine grade hoses, such as used in automobiles, is not recommended. Gasoline and diesel fuels have a profound effect on hoses. Fuel hoses should routinely wiped with a clean, dry cloth to check for excessive fuel order which could indicate leakage.

Strait of Megellan Blogspot

I like to welcome Capt Robert Reeder to cyberspace - please visit his new blog at http://wwwstraitofmagellan.blogspot.com. Robert is a well trained practitioner of marginal maritime advice and I encourage all of you to follow his exploits.

Zenith Maritime Services

What do we do (Seattle and Nation wide)?

· Yachts and Commercial Vessels Marine Surveys
· SAMS & ABYC
· Hull and Machinery
· Steel, Aluminum, Wood, Fiberglass
· Fastener Inspection
· UT Gauging – Coating Thickness Measurements
· Vessel Stability
· Consulting
· USCG and DNV Classed Vessels
· Marine Survey Classes and Training
· USCG Approved License Training AB to Master 200
survey@zenithmaritime.com – 360.471.6148

METAL BOAT SOCIETY FESTIVAL SPONSOR

PORT TOWNSEND WOODEN BOAT FESTIVAL SPONSOR

Metal Boat Society - August 21th - Port Angeles, Washington

I am speaking on Saturday, 21 August at the Metal Boat Society gathering at Port Angeles - here's my notes for my talk on surveying metal boats -

Metal Boat Survey Notes

aka

Preventive Metallurgy

Deficiencies –

• Wastage – Erosion - Corrosion (physical - chemical – electrical) – stray current and galvanic.

• Hull – Framing Damage (dents, buckling between frames, notches)

• Weld Seams – decay and faying surface corrosion (between hull shell and frame) from incomplete welds (usually a concern in recreational vessels).

• Non-marine metal alloys

Inspection –

• Visual and tactile observations

• Percussion testing

• Gauging – UT or Borings

• Probing

• Hull Potential

Steel Vessels -

• NVIC 7-86 Inspection and Repair of Steel Vessels

• Relative Inexpensive – good build strength – doesn’t fatigue easily

• Iron and Mild Steel (carbon steel) – rusts, wastes away in submerged in seawater at about the same rate. In still seawater, unprotected steel wastes at a rate of about 7 mils per year – so 1/8” (0.125”) hull plate will last about 24 years. In the splash zone wastes away at about 15 mils per year. An additional 2-knot current will increase wastage to 2X to 3X.

• Subject to galvanic corrosion, impingement (erosion), and weld decay.

• Protection Schemes – Coating (paints, epoxy, fiberglass), galvanizing, dry, Cor-Ten alloys, cathodic or impressed current protection. Remove all rust – don’t paint over flaking rust (galvanic cell – rust oxide is about 0.3 volts more noble).

Stainless Steel –

• Expensive

• Stainless – is just stainless not stain-proof. The addition of chromium (> 10%) increases resistance to corrosion due to the tight layer of surface oxidation (passive state). Marine grade stainless is austenitic (non-magnetic iron).

• Subject to corrosion in active state (no O2 acts like iron “crevice” - and w/o zincs in saltwater “pitting”), weld corrosion, stress and corrosion fatigue.

• Marine Grades 304 and 316 for deck fittings but suffer from pitting corrosion when submerged in still sea water.

• Questionable alloy content in foreign made fittings, stainless plated brass/bronze castings.

• Protection Schemes – expose to flowing water, air, cathodic protection.

• Unprotected Galvanic Potential – 316 (active) 570 to 680 mv DC, 930 to 1030 (passive) - (zinc reference cell).

Aluminum Alloys –

• ABYC Project T-1 and NVIC 11-80 deals with aluminum vessels.

• Marine grades are 5000 and 6000 series – hull plate is from the 5000 (magnesium) and extrusions are 6000 (magnesium and silicon).

• Hull plating - 5083 (higher weld strength) or 5086 H-116 (highest corrosion resistance) – for structural members 6061 T-6 (most common) or 6063 T-6.

• High strength to weight/thickness ratio.

• Fatigues easier than steel – prone to stress corrosion cracking (notches – sharp bends). Alkaline will cause aluminum corrosion – so better to protected using zinc anodes rather than magnesium (more electrically active).

• Prone to poultice corrosion.

• Aluminum is low on the galvanic scale – all other marine metals are a concern.

• Protection Schemes – coating (barrier coat), cathodic protection, avoid direct contact with dissimilar metals.

Copper Alloys -

• Brasses (Cu/Zn) – yellow, Admiralty (70/30), Naval Brass or Tobin Bronze (60/40) – all subject to alloy breakdown (dezincification – addition of tin/arsenic, helps to reduce galvanic protection), stress cracking.

• Manganese bronze commonly used in propellers, shafts, deck fittings is a high Zn brass (40%) with the addition of manganese to increase strength. Bronze and Cu/Ni Alloys (Zn free Cu alloys containing tin) – aluminum (90% Cu – 10% Al), silicon (3% silicon) – not subject to dezincification, Cu/Ni alloys (strong and resists corrosion).

• Present day bronzes can have questionable alloy content.

• Protection Schemes – selective use, cathodic protection.

Protection Strategies -

• Coat - paint metals especially in galvanic cells. Thoroughly coat weld seams.

• Good housekeeping – remove debris, tools, fasteners, etc - especially in bilges – spaces – voids – framing members.

• If dissimilar metals are causing unwanted corrosion – then one or more of the following should be done –

• Electrically isolate dissimilar metals.

• Select metals that are close to each other on the galvanic chart. If a coating is used, then use it on the cathode (the metal which is not going to corrode) because coating the zinc anode will reduce its surface area. Reduce the area of the cathode not the anode.

• Change the potential between metals (anodes – impressed current systems).

• Properly wire vessels to ABYC standards – no ground and neutral lines connected.

• Watch for stray current issues. Use galvanic isolator (double diode bridge) – transformer.

Cathodic Protection -

• Every boat is a battery – some larger, some smaller.

• In marine environments – we struggle everyday with galvanic corrosion and cathodic protection.

• The problem - the corrosion (and resultant damage) that occurs at the anode of a galvanic cell is caused by the flow of electronics (galvanic current) from the anode to the cathode through an electrolyte. Usually – the damaging galvanic potential is less than 1 volt DC.

• In 1824, Sir Humphrey Davy mounted iron anodes on the copper hull sheathing of the HMS Samarang to prevent the copper from corroding.

• The plan – reduction or prevention of corrosion of a metal by either coating and or making it cathodic by the use of sacrificial anodes or impressed current to change the protected metal’s potential voltage by at least 200mv DC.

ABYC Project E2, Table II
Recommended Range of Cathodic Protection
(AG/AGCL reference cell in sea water flowing at 8 to 13 ft/sec, temperature range 50 to 80˚F)

Fiberglass Hulls	-550 to -1100mv
Wood Hulls	-550 to -600mv
Aluminum Hulls	-950 to -1100mv
Steel Hulls	-850 to -1100mv
Non-metallic Hulls with Aluminum Drives	-950 to – 1100mv