Net Dynamic Menu by v4.3.0


190 Amp Yanmar kits

240 Amp kit for Yanmar

330 Amp kit for Yanmar

190 Amp Yanmar belt kit

Fast Flow emergency bilge pump- Amazing flow

Inexpencive three step regulator

Marine books by
Scott Fratcher

Fast Flow emergency bilge pumps

ElectroMaax battery chargers

Fast charge rates

Inexpencive universial regulators


Choose the right hull material for your skills

Before purchasing a boat consider if you’re willing to take on the type of work needed to maintain and repair the hull.


Repairing the hull considerations

The ability to repair different hull materials is often a matter of the type of work one is willing to tackle. For some grinding a fiberglass hull is pure agony, while, For others cutting steel with a hot torch can be a torturous experience. In this article were going to discuss the basics owning and repairing three of the major hull types-
• Fiberglass
• Steel
• Aluminum
Let’s start by considering some repair advantages and disadvantages of each hull material.



• Resin and fiberglass are available the world over
• It’s a very basic technology known in the most outback locations
• Repairs are relatively cheap
• Very few power tools are needed
• Often the DIY can make his own repairs



• Repairs available in the most remote locations
• Needs only the most basic of welding machines
• The constant paint maintenance can overwhelm a yachting vacation
• Steel boats have about a 30 year life span due to interior rust
• Steel produces high “sweat equity” return on effort invested due to the low cost of materials



• Difficult to find repair facilities in remote locations
• Specialized welding equipment is needed
• Low, low maintenance. No rust. No paint above the waterline or in the bilge.
• Highly susceptible to electrical corrosion
• The “right” aluminum must be used in each repair.
• The hulls are loud and easily transmit engine and equipment noise along with waterline noise
• Difficult of effectively insulate
• Reacts poorly with wood

Let’s consider an overview of repairing each type of hull material from an owner’s perspective.



Fiberglass is a strong, and almost inert material. It’s possible to own a boat for years without ever having to repair the hull except for a hull polish.

The four most common reasons for needed hull repair are-
• Impact
• Blisters
• Poor workmanship
• Fastener failure



Impact from striking a reef, another boat, or even cosmetic damage from normal wear and tear are all repairs within the scope of most DIY boaties.

The repair typically starts with the use of a grinder, followed by-
• Gelcoat removal till fresh, clean fiberglass is reached
• New glass cloth is laid over the damaged area
• Resin is painted over and into the cloth
• The repair is left to cure and then ground smooth
• Paint or gelcoat is applied to provide a finished look

This type repair is not typically considered difficult, but the grinding of fiberglass can be an itchy, uncomfortable job. The trick is to start the work by gearing up with proper protective gear such as-
• A Tyvex suit
• Gloves
• Respirator
• Safety glasses

Tip-Too often we see the DIY grinding fiberglass in shorts, tee-shirt, thongs. If you find you started a job in this manner and now are paying the price late in the day by itching and scratching try a cold shower and vinegar rinse. The cold shower prevents your pours from opening allowing the ground glass to rinse away without further penetrating your skin while the vinegar can break the bond of the polyester or epoxy resin allowing the sticky remains to be rinsed off without the use of harsh chemicals.



Often fiberglass boat owners will comment on how they can maintain much of their boat with a few simple tools. The list often starts with a small 100mm angle grinder coupled to a 36-40 grit grinding disk with a hard rubber back. This inexpensive grinder and interchangeable heads is available at hardware stores the world over and allow basic repairs to the hull.



When making a repair the DIY will have a choice between polyester or epoxy resin. Polyester is less expensive and often what the boat was originally built from. Epoxy has a higher price tag and can only be over coated with more epoxy, but its adhesion properties are much higher. Short of other knowledge to make a decision on it’s often best to make a repair with epoxy.



Osmosis, or the “pox” is considered a major downfall of fiberglass boats. Blisters often show up on haul out and can mean a high priced repair. The long, challenging fix often revolves around stripping the complete gelcoat from the bottom of the hull using an electric planer like device. The boat is left to dry while the moisture content of the remaining hull is checked. Once the hull is considered dry enough a new layer of epoxy and glass is laid over the complete bottom followed by gelcoat.

Repairing the “pox” can tax the DIY. One method to make the job easier is to hire out the initial stripping of the bottom. This gives the DIY a starting point to start the labor intensive repairs.


Hull flex

Oil-caning, or the hull skin flexing between the ribs often happens in thin production glass boats. The owner might first notice gelcoat cracks running parallel and near to the ribs. Left to their own devices the hull will eventually begin to form a crack.

The standard repair is to add longitudinal stiffeners to the inside of the hull. The project can be as simple as ripping a piece of PVC pipe lengthwise to lay against the hull and use as a mold to add a few layers of fiberglass cloth. The difficult part of this job is removing the interior of the yacht to reach the hull inside of the hull.

Note-Boats built pre 1970’s did not tend to oilcan as the hulls were made thicker.


Clean lines

Fiberglass hull tend to have nice clean edges, radiused curves, and fast water drains. This is because one of the big advantages of building a boat in a mold is these delicacies can be thought out and built into the mold ahead of time so each successive boat has some elegant features.



Glass boats, especially older production boats can be a great bargain costing much less than a “one off” version. Production boats also tend to have a known history and value. A quick Internet search will show the basic selling price and the boats reputation such as typical speed, best point of sail and even know design flaws.


Daily maintenance

Glass boats are often thought of as a low maintenance boat owning experience. A simple polish and waxing is often all that is need. Use a buffing machine with rubbing compound followed by an application of wax during the yearly maintenance can keep an old boat looking new.



Glass boat pitfalls

Deck leaks, fitting maintenance and lightening strikes are often considered the big three pitfalls of a fiberglass hull.

While not really a hull repair, fiberglass boats are notorious for deck leaks and dealing with them is part of living on a fiberglass boat. Water finds it way into one of the many bolt holes securing a hatch, sailing track, or deck fitting only to migrate through the overhead to drip in some inconvenient place.

Some tricks used to find the source of deck leaks are-
• On a hot sunny day blast water at individual deck fittings. The idea is to limit the places water could have entered the boat while testing.
• Try to get to the underside of the leaking fittings. Dry the areas as much as possible then use toilet paper laid over the fittings to identify the “wetspot” showing the individual leaking bolt.



Fiberglass boats are held together by fittings. These are the nuts and bolts that secure the chain plates to the hull, the bolts that secure sailing track to the deck etc. Each bolt is a source of corrosion and possible leak. Metal boats don’t have this problem and it’s often one of the prime advantages of a metal boat over glass.


Lightening strikes

Fiberglass boats are susceptible to lightening strikes. While New Zealand in itself is not often thought of as a lightening prone area, if the boat is taken cruising lightening zones will be encountered. Metal boats are almost completely immune from lightening strikes. A glass boat can suffer thousands of dollars in damage after a severe strike.



Aluminum hull repair

Repairing an aluminum hull is relatively simple. The work is clean and the welding easily learned. The challenge revolves around finding the right equipment. Let’s look at a few basics of aluminum repair.




Cutting aluminum is most often done with a powerful circular saw and a carbide tip blade. Amazingly a good carbide blade will cut right through a sheet of aluminum leaving a near perfect cut. Be sure to wear hearing and eye protection. The flying aluminum chips are notorious for their sharpness.

Tip-Blade noise can be reduced by first cutting into a block of beeswax followed by the aluminum cut.




Welding aluminum is fast and easy, but it takes a lot of power to maintain the molten welding “puddle”. The power source must be clean and consistent thus a large generator or good shore power is needed.



The welding kit

Let’s look at a typical aluminum welding kit. In the welders hand is a spool gun. A spool gun is a welding lead that can be held in one hand with a small spool of aluminum contained in the handle. The spool gun is powered by a power source, most often a DC inverter welder powered by a 6KW or larger power lead. The welding arc itself must be covered with an inert gas, most often Argon. This means a metal cylinder of gas and a regulator must be included in the welding package.

While all this gear has dramatically shrunk in size over the last few years the welding kit bulk is still outside what most boats would carry aboard. This means when a repair is needed the first step is the yacht must find a competent shop. Inside New Zealand this is relatively easy. On the cruising circuit finding a good welder willing to come to the boat can be a challenge.



Aluminum boat factoides

• The welding process for aluminum is faster than steel. This means it costs less labor time to lay the same amount of weld in aluminum.
• Aluminum is less expensive to work than steel since the cuts are made with a circular saw rather than a “gas ax”. This means no buying expensive gasses and less fire hazard from flying cutting sparks.
• Aluminum does not need to be treated when the weld is complete. This translates to considerable cost savings when compared to a steel weld. Steel requires cleaning (sandblasting) and five coats of paint to prevent rust.
• Aluminum has no life span. A steel boat lasts about 30 years till the cost of maintenance begins to overwhelm the budget. An aluminum boat that has been taken care of will still be “good as new” in the same time period.
• Copper and mercury are big killers of aluminum. One drop of mercury (from a broken bilge pump float switch or thermometer) will eat through the hull in just weeks. Copper dust from bottom paint tracked onto shoes from walking through boatyards can leave a groove in an aluminum deck.


Insulating an aluminum hull

Aluminum hulls are difficult to heat and cool. Often we hear “just insulate it”, but this is not really an appropriate answer. Our personal sailing yacht for over twenty years has a steel hull and aluminum cabins. This means I live in a world comprised of half aluminum and half steel. The steel has one inch of laid in insulation while the aluminum has two inches of blown in insulation with a half inch of wood over the top.

Standing inside the boat on a cold day it is readily apparent the cabin tops are “sucking” the heat from my body. In cold climates the effect is even more dramatic. Screws into aluminum with exposed heads form icicles inside the boat while exposed steel simply condensates.

In Alaska areas of exposed aluminum built up ice over a half inch thick with the diesel heater is set to maximum. Meanwhile the steel may be chilly, but it has yet to form ice on the inside of the cabin. This might explain why aluminum makes such good cookware.



Repairing steel

Steel is often considered “easy” to repair, but it should also be considered “dirty” to repair. Every aspect of the job leaves a mess. Weather its grinding dust left on the deck, burned ash in your lungs, or steel dust in the air that covers surrounding boats with rust streaks, steel messy to work with.

Most often steel hull repairs are needed after an impact, or a rust hole has opened up under the water line. Typically the repair steps are-
• Decide on the amount of plate to be changed by use of ultrasound or visual inspection
• Mark the edges of the cut
• Cut the straight sections with a cutting disk or plasma cutter
• Cut the curved corners with a hole saw, gas ax, or plasma cutter
• Cut a new piece of plate and hold it into location
• Tack the plate to hold its position.
• Weld the outside of the plate back-stepping to prevent warping
• Grind the weld from the inside and re-weld. Finish with another weld from the outside.
• Wire brush or sandblast and paint on five coats of epoxy.



Some tricks to making steel repairs-

• Use high quality electrodes. Low quality electrodes produce low quality welds that tend to crack on cooling or worse during subsequent impacts.
• Pay particular attention to the grinding out of bad spots on a weld. Much time is saved by grinding deeper to clean out the impurity and thus produce a good second weld.
• Don’t rush the welds. Be sure to take time to let the weld cool. Distortion, weld cracks, and rusting welds often come from overheated welds.



Look at a piece of raw steel and you’ll notice the surface will either shiny, lightly rusted, or black. Black is the left over mill scale remaining from the production process. Mill scale MUST be removed prior to welding or painting. This is because mill scale is not really bonded to the steel so it will eventually lift off ruining the best paint job.

Worse, mill scale is located on the galvanic action chart slightly higher than steel, thus the mill scale will cause the steel to rust in a marine environment. Ever see steel repair that has simply rotted away in a matter of years, or in some cases months? This is most often caused by the thin layer of mil scale that was not removed during the repair process.



Removing mill scale

Mill scale is difficult to remove. It is harder than steel and thus difficult to grind. To remove mill scale before a repair try-
• Buying steel plate that specifically had the mill scale removed
• Leave the plate exposed to the elements for a short time to allow the surface rust to form thus weakening the mill scale
• Grind or sandblast the surface of the plate
• Acid soak the steel plate to lift the mill scale

Steel welding gear needed




Welding gear for steel is cheap and getting cheaper. Modern welding machines are solid state, weighing about three kilos and can be fit under a single arm. The basic machine can be purchased as stick welder, or for a few hundred extra dollars the tig option can be added allowing welding of special metals such as stainless steel, bronze, brass etc. A modern welder can easily be carried on the smallest of vessels for repairs in remote locations. Steel does not require the high current of aluminum to weld, thus a much smaller generator can be used.



Plasma cutter

A plasma cutter is a special machine that cuts metal by using compressed air and electricity. This makes them specially suited for boats where tanks of special gas can be difficult to come by. The compressed air can be supplied by a small onboard compressor, or even the low pressure side of a SCUBA regulator. Expect to use at least a 4KW genset to power the newer smaller machines.

Note-In New Zealand machines can be purchased that are a four in one. Stick welder/Tig/Mig (power source)/plasma cutter. While a little larger than a single welder these new welding machines give almost any boat complete shop facilities in one package.




While there is no perfect hull material choosing “your” material is often a matter of forethought and what “devil” your willing to live with. By taking the time now to decide on the work you’re willing to perform you can narrow you search in purchasing a new boat.

Note-Much of the background information for this article was taken from Scott’s new book, “Metal Boat Maintenance and Repair” available at


Yachtwork Question-

The answer to last month’s question about the two types of load a breaker is designed to protect against is- A breaker must protect against long slow overload and a direct short. The long slow overload is often regulated by temperature build up through a bimetal strip. During a direct short the load must be released immediately or the wires will burst into flames. The breaker does not have time to heat up and release, therefore a second “bullet” breaker is built into a breaker. A bullet breaker looks like a bullet and has a few wraps of wire around it producing enough magnetic force to “shoot” the bullet from its seat instantly disconnecting the load incase of a direct short.

Q-We all know if you want to cool a piece of hot steel you put it into a bucket of water, but what is the ratio of heat holding ability of water to steel. In other words if a kilo of steel at 100C were dropped into a bucket containing a kilo of water at 0C what will the approximate final temperature of the water and steel be? (Ignore heat lost due to outside forces such as air temperature)


Choose the right hull material for your skills

Glassing the bow of a fiberglass cat

Laying the glass on in layers.

No matter what type of work you perform take the time to protect yourself.

Mystery crack in the bow of this cat.

Repairs to fiberglass

Aluminum hulls needs special welding gear. Mig machines and Argon gas

Deep pitting in aluminum can mean changing plate.

This pitting was caused by poor radio grounds.

Repairs to most hulls can be made in the water

Look at the lack of material inside the hull

Just a gaping hole in the glass. No wonder it cracked.

A plasma cutter can make cutting metal plate a breeze.

Steel welds need to be protected. Spray is an easy way to apply a good thick paint covering.

Removing mill scale from steel before a boat repair.

Steel plate being changed. View from the inside.

Steel plate change. This simple work can double the life of a steel boat.

The old plate does not come out easy. See the parts that had to be cut to bits.

Welded and repaired steel hull waiting for paint.

A fiberglass cat still needs welding on the metal bits.


The following photos are from the article on corrosion that can be seen here

Basic Fast Flow Emergency Bilge Pump Kit

$599USD plus shipping


Fast flow pump installed.

Always ready - Always pumping

Pump arrives in parts for easy install. No need to remove the prop shaft

Prop shaft bilge pump installed and ready for use

Impeller blades split in two for easy install and come in various sized to meet every boat's needs

Pump is ready for installation.

This is a safe boat with the Fast Flow propeller driven bilge pump

Example of a propeller driven Fast Flow bilge pump in operation

Fast Flow emergency bilge pump in position ready to save the day


Basic Fast Flow Emergency Bilge Pump Kit

$599USD plus shipping


Order your books by Scott Fratcher here


Metal boat repair and maintenance. A must read for any steel boat owner.

Print: $31.10

Download: $12.00


How to repair a steel boat without sandblasting. Special report.

Download: $4.00


In order to get a good job as a marine engineer we need a marine engineer licence, commonly called a Certificate of Competency

Print: $39.49

Download: $29.50

How to get a job on a mega yacht as a marine engineer? It can be done without a licence.

Download: $4.00


50 money making ideas run from a boat

Print: $39.90

Download: $39.90

Make money with boats? You bet! It's done every day, but most people won't tell us how they did it. This book is a tell all to give the layman the tools needed to start their own onboard cruising business.

How to make money with boats has become an instant classic selling around the world making dreams come true. If your planning a cruise, or your know someone who is this is the perfect book.

Print: $39.90

Download: $39.90


Print: $21.37

Download: $9.00


How to buy boats cheap? Dozens of tricks used by adventurers around the world every day. This book is a must read for anybody ready to purchase a boat.


Print: $29.96

Download: $9.00

The race was a heartbreaker, but eventually Earthrace took the round the world speedboat record. This book is the log and blog of the 2007 race where Earthrace set dozens of fastest ocean record crossings.


Download: $12.00

Earthrace in color. The same book as above, but in vivid color to bring all the race moments right to the reader.


Print: $14.97

Download: $9.00

Anchor King is a narrative book of short stories of the Sausalito California waterfront in the late 1980's. Anchor King contains the award winning short story "Sex Toys?"

Print: $115.47

Download: $5.00

Tjalk Operator's Manual is an example of how to build a yacht manual. Over 300 pages showing how to drive a twin engine, single rudder vessel and much more.


Click here to purchase

"Earthrace-First time around"
by Scott Fratcher

Download Now for just $9.00





   © Team Yachtwork 2007