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   A Guide to Hull Blisters There is one phrase that causes a lot of anxiety during a haul-out: "Blisters have been observed on the hull" It’s often treated like a terminal diagnosis for a fiberglass hull, conjuring up images of a boat slowly dissolving from the inside out. But anyone gets too excited and assumes the boat is destined for the scrap heap— take a deep breath. While hull blisters are certainly a nuisance and can be expensive to fix, they are rarely fatal. Let's peel back the layers on what causes these bumps, why the "O-word" (osmosis) gets thrown around too much, and what it actually takes to fix them. What Exactly is a Hull Blister? In simple terms, a hull blister is a fluid-filled bubble that forms underneath or within the fiberglass laminate and the outermost protective layer of your boat, known as the gelcoat . When we pop them during a survey, they usually expel a pressurized fluid. If that fluid smells like strong vinegar, it’s a classic sig...

Mastering the Art and Science of Moisture Meters

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  In the world of marine surveying, few tools are as misunderstood—or as controversial—as the moisture meter. To the uninitiated, it looks like a "magic wand" that can instantly tell you if a boat is a lemon. To the seasoned surveyor, it is a sophisticated instrument that requires a blend of scientific understanding and artistic interpretation. If you’ve ever watched a surveyor press a small device against a hull and wait for a beep, you’ve seen the process. But what is actually happening behind that digital display? Drawing on the standards set by the International Institute of Marine Surveying (IIMS) in their informative guide, The Use of Moisture Meters on Small Craft , let’s pull back the curtain on the art and science of moisture detection. The Science: It’s Not Actually Measuring Water The first thing every boat owner should know is that a moisture meter doesn't "see" water in the way we see it in a glass. Most marine meters (like the Tramex or Sovereign ...

Seeing the Unseen: The Integration of Infrared Thermography in Marine Surveying

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In the world of marine surveying, we often say that a surveyor is only as good as their eyes. But even the most seasoned professional can’t see through a fiberglass hull or detect a loose wire buried deep inside a main distribution panel. That’s where Infrared Thermography (IRT) comes in. Over the last few years, thermal imaging has transitioned from a high-end luxury to an essential tool in my kit. It allows us to perform Non-Destructive Testing (NDT) by capturing the heat signatures emitted by an object. If there’s a problem, there’s usually a heat signature associated with it. Here is how we are using thermography today to keep vessels safe, efficient, and seaworthy. 1. Identifying Moisture and Delamination in Hulls For FRP (fiberglass) boats, moisture is the silent enemy. Traditional moisture meters are great, but they are one data point.  Surveys are most effective when multiple data points can be assembled to make a fulsome assessment of the vessel.  A thermal camera a...

Directional Control Under Sail: What Type of Rudder Does My Boat Have?

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In the world of sailing, the rudder is more than a steering mechanism; it is a primary control surface that dictates the vessel’s "feel," its ability to track upwind, and its safety in heavy weather. Designing a sail boat's rudder requires a specialized understanding of how heeling forces and hydrodynamic lift interact with various construction materials. The Dynamics of Helm and Balance Unlike motor vessels, which generally remain upright, a sailing vessel operates at varying angles of heel. This change in geometry shifts the center of effort and affects the rudder’s efficiency. The "balance" of a sailing rudder—the percentage of surface area forward of the stock—is a critical design choice. A balanced spade rudder (20–30% area forward) reduces the physical effort required by the helm, providing a light touch even when the boat is powered up. Conversely, a less balanced or unbalanced rudder provides more "feedback," allowing the sailor to feel the p...

Do you know your keel? A thrilling discussion of keels!

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A vessel's keel is not merely a counterweight; it is a critical structural appendage that defines the vessel’s hydrodynamic efficiency and ultimate stability. Understanding the nuances of keel design and the rigors of its maintenance is essential for ensuring both the longevity of the hull and the safety of the crew. The following guide outlines the primary keel configurations, material considerations, and the technical protocols for maintaining structural attachment. Primary Keel Configurations Keel selection is a balance of lateral resistance, center of gravity (CG), and wetted surface area. Full-Length Keels: Common in traditional blue-water cruisers. The keel integrates directly into the hull's lines, providing superior directional tracking and protecting the rudder and propeller from debris. Fin Keels: Characterized by a high aspect ratio, fin keels offer reduced drag and improved maneuverability. However, they exert higher concentrated loads on the keel-to-hull joint ,...

Measure Once, Race As Much as You Can! Your ORCi Pre- Measurement Guide

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  Having additional measurements add to your ORC club certificate or obtaining an ORC International certificate can in many cases improve your outcome on the race course. The first step is to visit the ORC – Canada website and submit your application. Once this is done a measurer will confirm with you the date and time to conduct all your measurements.   You will require a crew of at least 3-4 depending on vessel size in order to support the measurer.   An ORCi certificate isn't just a piece of paper; it makes our local racing as fair as possible.   ORC Canada has dedicated and well qualified staff to support competition in BC and across Canada. To get the most accurate rating possible, the boat must be in its "purest" form. If the measurer arrives up and your boat is still full of half-eaten sandwiches and soggy dock lines, it will be a long day. 1. The "Light Ship" Standard The most common mistake owners make is failing to reach Measurement Tri...

The Critical Interface: A discussion of Composite and Alloy Thru-Hull Fittings

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Hull inspections frequently center on the integrity of underwater penetrations. The choice between traditional alloys and modern fiber-reinforced composites is a decision that impacts not only the vessel's maintenance schedule but its long-term structural security. The marine industry has seen a shift from the historical dominance of bronze to high-performance polymers. Below is a comparison to assist owners in making an informed decision when replacing their boats thru-hulls. Fiber-Reinforced Composite (Nylon/Polymer) Modern composite fittings, such as those manufactured from glass-reinforced nylon (e.g., Marelon or TruDesign), have gained widespread acceptance in both recreational and commercial sectors. Key Advantages: Electrolytic Neutrality: Being non-metallic, these fittings are immune to galvanic corrosion and electrolysis. This eliminates the need for bonding to the vessel's sacrificial anode system. Weight Efficiency: Composite assemblies are significantly lighter th...