Dezincification

Dezincification can be recognized by the metal colour, shine and texture. In the image below, for example, the section of a bronze propeller blade with distinctly dezincified areas, recognizable by their pinkish colour, can be noticed. Black areas are rests of antifouling paint. White residues are housings of tubular worms and barnacles.

Dezincification can be limited to the surface or may well extend into the metal body.

The marks on one of the dezincified areas on this prop blade have been inflicted by the surveyor’s pocket knife tip. Blows by the pocket knife in the sound areas, in contrast,  have left no marks whatsoever! Dezincification compromises the bronze metal’s mechanical properties significantly and will lead to failure of submerged metals and, if left undetected, to heavy, subsequent damages. Usually, dezincification will slowly develop over time, but this is not a firm rule: A short circuit somewhere on board may lead to a quick failure of one fitting over short time, say few days.

For example, a short in a recently replaced deck light on one spreader may lead to power the mast, which, over the forestay may put the bowsprit’s waterstay under voltage. As a result the waterstay fitting starts to dezincify. This example is a real case and it required a lot of effort and wit to narrow down and eventually find the shortened deck light.

If one dezincified metal appurtenance is identified in the submerged hull, one should inspect the vessel for further damages, including damages to metal bonding and undesired galvanic shorts to one or the other metal fitting. A galvanic corrosion survey with a reference electrode may be required.

The author of these lines distinctly remembers the failed skin fitting on his own boat, which he plugged with his finger until somebody around heard him shouting for help….

Fair winds.

The Shackle Revisited

During our yacht surveys we rarely see shackles that have been moused. We remark that regularly in our reports, but I am not sure whether our clients all appreciate the importance of this.

Mousing is a simple and good practice to secure the bolt of a shackle to prevent it from getting unscrewed unintentionally. I was reminded of this in a marina in Croatia where the pontoons had been shackled to the quay and all shackles had been moused.

Galvanized shackles tend to unscrew when they are under a pulsating load. Even if you tighten them carefully they eventually get unscrewed because the micro-stalactites of the zinc coating eventually get faired under the strain. Stainless steel shackles are also prone to unscrewing as the bolt’s thread usually is seated and rather slippery in comparison to galvanized hardware.

Using rope or galvanized wire is good for mousing, monel wire is even better, but even a cable tie will do as long as it is inspected regularly.

And by the way, the safe working load of shackles is determined by the diameter of the thread root, which is often smaller than the diameter of the shackle body.

Inspect your hardware, in particular the shackles, regularly. This way you can avoid losing your ground tackle. Losing ground tackle happens – usually at a time when it is least expected and most inconvenient, thus maximizing damages.

Yacht Ownership

As marine surveyors we are offered a myriad of “stamped papers” which are served as a proof of yacht registration, or documentation or flag certificates – basically as proof of yacht ownership, or support thereof. Often a quick but careful initial assessment of documents received is required in order to decide whether they are legitimate. Sometimes we deal with poor scans, photostats, or whatever happens to be at hand. …

My Family and other Animals

“Dear Naci, further to our conversation, please could you contact our client to assist him in arranging to get his vessel fumigated to eradicate some scorpions that have been found on board.” The instruction by the insurers’ claim handler was brief and somewhat frightening. My first thought was “Is there an infant on board?”, as, albeit very rarely, the local scorpions have been known to poison kids to death. …

Sogged Rudderblade

Surveyor’s Opinion to Strapped Full Rudderblade on a Taiwan built Force 50 Ketch: “At my inspection the GRP rudder blade had been dismantled for a while and was placed under the vessel. About 10 bores of about 40 mm diameter had been drilled into the blades sides/ cheeks with a punch drill. Most of the bores had reached the foamcore of the rudder blade, some had reached the opposite laminate. At the time of my inspection I could confirm the uniform and very high moisture readings reported before. The foam core was partially darkened (as it happens with moisture ingress) but looked mostly in honey colour. From the one core sample I could inspect, I concluded that the adhesion between the core and the GRP cheeks of the rudder was not bad. …

Surveyor’s Comments – Fatigue Crack on a Shaft

“Surveyor’s Comments: According to my analysis of the fracture surface and observations on board, the shaft is broken due to fatigue and not by striking a submerged object or catching a rope etc.

The fatigue fracture surface is characterized by its smooth appearance with almost no plastic strain. Beach marks[1], indicating the position of the crack front at various stages during propagation, have a typical semi-elliptical shape. The final rupture (low in the image of the fracture surfaces) is ductile[2]. The final fracture surface is very small in comparison to the area of fatigue cracking. …

Surveyors’ Experience with Crafts of the Ferretti Group

The senior surveyors of the marineSOLUTIONS team, Capt. Naci Arıcı and Dr. Yusuf Civelekoğlu, have been at some stage part of a Ferretti Master Service. Formed on 31.3.2009, this was, at that time, the first and only Ferretti Master Service outside Italy. The Ferretti Group used to appoint only few of their service points as Master Service, and only if a service point had proven to be able to carry out complex repairs consistently to a good standard.

As the Ferretti Service and later the Master Service, we have experienced thousands of issues with the group yachts, thus covering almost all aspects of the vessels. One incident, namely, the grounding of an 88 foot Ferretti, we remember very well.

That 88 foot motoryacht had run aground at full cruising speed. She survived, came off and was fortunate to be quickly towed to and drydocked at a marina nearby.

As can be imagined, the vessel’s aft had suffered severely. All propulsion elements of both sides – from props to gearboxes, were heavily damaged. Both brackets were stowed in, causing heavy structural damage to the aft sections of the vessel. There was significant flooding damage.

Our staff inspected the vessel and prepared a quote, which was eventually approved. In that process, we patiently dealt, next to the captain, with the owner, the insurance surveyor and the insurers. Then we arranged for the spare part logistics, the repairs, the sea trials and the vessel’s delivery.

In the interim, additional requests from the owner started to come in due to our good performance. In the end, we completed a list of more than 300 work orders in addition to the grounding damages.

Before the incident, the vessel had been neglected for a long time until the crew took her over. This deferred maintenance had created issues in addition to the grounding and flooding damages. We replaced the generators, sanitized the fuel tank, and dealt with a serious termite invasion inside the wall panels and the floorboard frames. We managed to resolve the severe Naviop irregularities.

The project lasted only 12 weeks, and the budget exceeded 300.000 Euros.

The delivery of the vessel was a complete success for both parties.

The vessel left the marina at the onset of winter and sailed to Italy.

About three months later, we received an unsolicited and sincere letter of recognition from the captain. He thanked us for providing “high-quality work and great service” according to European standards.

It is much desired that a surveyor has a background with hands-on experience in the subjects he deals with.

Dr. Yusuf Civelekoğlu, CMI

Some Images from the Project

Propellers after the incident

Hull structure around the p-brackets

Re-laminated hull

Re-laminated interior

Re-bonded shaft logs – interior and exterior views

Fuel tank before – after photos

Left: Condition of the interior walls and floorboard panels. Right: Capillary roads of the termites.

Condition at the launching