Straight Talk


General Information


Here you will find a range of helpful topics for  choosing the right trailer configuration,  rollers or bunks, advantages and disadvantages.  

Plastic materials rollers and bunks are made of, common problems and some safety advice.

Browse through and enjoy. 

I just bought my first boat… any tips for me.

Make yourself a "Best Mate”.

This is a piece of rope spliced permanently to the bow of the boat.

When you get a new boat, the first thing you should do is go and buy a piece of rope that will go from the bow to the stern of your boat.

Most boats have a crucifix or cleat on the bow to tie off your anchor rope.

Splice a loop in one end tight around this, as this will be a permanent feature.

If you don't know how to splice, have a go,  it is rewarding and helpful.

Cut the rope to a length that if it falls in the water it can not entangle the prop.

Then splice a loop in the stern end . You can use the back loop to make a lasso or  a number of other useful uses.

Lay the rope alongside the gunwale past the windscreen or cabin and then hitch it around your starboard transom crucifix or cleat  to keep it out of the way.

It is a permanent feature of your boat and will be your Best Mate when you are on your own.

What will I use this rope for ?

Many things.

It is great and handy if you have to operate your boat on your own.

You will find many practical uses, you can drive up to a jetty and throw it to somebody to secure your boat, you can often flick it yourself around a pile, helpful if people fall over board, and it is particularly useful if you have to  launch and retrieve your trailer boat alone.

It does not matter if your boat is a 10 foot dinghy or a 40 foot game boat… if you are the sole person on board it will become your Best Mate.

Any tips on launching my trailer boat alone?

Yes … remember to put the bungs in first.

At one time or another for various reasons we may need to launch our boat or put it back on the trailer without help... on their own.

Size does not matter and in fact a the bigger the trailer boat the easier it often is.

For a dinghy, no contest, just back your trailer down the ramp…..undo the safety chain and winch and push it off and with  your “Best Mate Rope” …  drag it aside up the beach or to the jetty and secure it  while you park your car and trailer.

It is not much different with larger heavier boats, like  20’ or 26’ etc, and the technique depends on your trailer configuration.

Rollers, skids or bunks?

Most boat ramps are around 7 to 8 degrees of angle and the advantage of bigger boats is the stern can get some buoyancy due to the ratio of length, water depth and ramp angle.

Importantly the leg cooling intake must be in the water before starting the engine  and you need some upward tilt on the leg to avoid contact with the concrete.

If your boat trailer is bunk or skid then back it down until the leg is able to suck cooling water.

Take your Best Mate rope and drop the spliced stern end over the winch post.

Undo the safety chain and remove the winch strap and climb aboard.

Tilt the motor at about 30 degrees up, start it up and apply reverse power.

The prop will drag your boat off the trailer and slight angle of the motor will provide lift on the transom  and also force water forward under the stern and depending on engine size and power can lift the stern ….and so boat will slide into the water with your Best Mate rope securing it to the trailer.

Switch off, jump off and with your Best Mate, pull your boat to a beach or jetty adjacent, secure it and go remover your car from the ramp to the car park.

With roller trailers, a heavy boat won’t usually roll off a trailer on a 7 or 8 Degree angle, however if you back down to the water and stop short... about a metre from where you would normally place the rig for launching, then undo the safety chained winch strap  and place your Best Mate over the winch post.

Jump back in the vehicle and reverse that last metre and stop with a sudden and hard braking action… the boat will usually just roll off and be secured to the trailer by your Best Mate.

You can use your best mate to pull your boat to a safe site, then  remove your car to the car park.

Loading your boat on the trailer is again helped by your Best Mate.

Idle into the ramp area … find a spot to secure your boat while you get your car and trailer, back it to the water and with your motor leg tilted slightly up so as not to hit concrete, drive your boat on to the trailer.

Spitfire Trailers, offer as an extra accessory,  a set of  simple and inexpensive Easy Load Guides. With these guides fitted,  you can drive the boat between the outer bunks or rollers without the boat hitting the metal of  the trailer when loading.

What is the best trailer for my boat… Bunks, Rollers, Skids or a combination of each.

Selecting the type of trailer to suit you depends on a few things including hull material, tide variation at your location and your experience... and price.

Let's look back a little at the evolution of the boat trailer.

The first record of boat use was found carved in sandstone and dated 10,000 BC.

The first trailer, was a chariot and it’s first use it’s is dated to about 3,000 BC.

However it was not until after WW ll that the development and availability of both aluminium sheet and GRP Fibreglass provided a range of light boats that were ideally suited for towing.

Around 1955, the smell of wood shavings in boat sheds changed to resin fumes and the noise of riveted aluminium could be heard.

Trailer boats were born, the boat and trailer came together and the industry boomed to be the common site we take for granted today.

Ironically, it has gone the full circle and it is not much different today from the early trailers. 

The first trailers were called skid trailers because the boats we’re winched up onto skids. Typically these early skids were made of a soft wood like pine and evolution saw various covers from rubber to carpet to plastics.

As metal came into skid fabrication it had a downward bend at the back.

Then with the development of plastics rollers came into use on boat trailers.

As with many things, Americans were the first to embrace boat trailers with rollers and the industry saw a massive move away from skids.

Australians were slower to turn to rollers as they were initially very, very  expensive and often they were only the prize of the rich for larger boats.

Some in the trade who wanted to keep their boat, motor, trailer package prices low, spread the rumour that rollers were not suitable for an aluminium boat as they dented the hull.

Not true on a properly set up trailer, as little weight should be on the side supports,  but it stuck and rollers became predominantly the choice for fibreglass boats and boats were winched up onto the rollers.

This has remained almost until today where the trend has turned a full circle and gone the other way back to skids… except they don't call them skids any more... rather bunks.

Why the name bunk and not skid…. 

People once respected their machinery more than they do today and never put the wheel bearings or hubs in the water when launching their boat or retrieving it… so the boat had to be winched up the skids onto the trailer.

Today the trend, again first from America, is to back the trailer into the water as far as you can until the towing vehicle's wheels are touching the water … or worse ….and the boat almost floats of the trailer… and on return the same process and as you drive out of the water, the boat settles on the ‘Bunks”.

Hence the name Bunks.

Today is is almost impossible to see or buy a new roller trailer in the US… and the trend toward Bunks is now happening world wide... and for some good reasons as well.

So what are the advantages and disadvantages of rollers or bunks.

To answer that we must first look at the function of a boat trailer.

In an ideal situation, the boat should be fitted and adjusted so that;

1. 70% to 90% of the boats weight is supported by the keel.

2. The Centre of Gravity is over the axles.

3. 10% of the total boat and trailer weight is on the tow ball.

4. The bunks or side rollers keep the boat upright.

This configuration gives the safest and most stable towing and braking balance and in this configuration.

The keel is the strongest part of any boat and it supports the majority of the weight and the side rollers, bunks or skids keep the hull upright.

Large boats have the added advantage of long boat trailers and can place your transom further into the water so this makes them ideal for no rollers…  just bunks.

Shorter boats / trailers, may work better with side bunks and keel rollers.

The tide height and ramp degree can also come into play as some Australian cities have less than 1 metre difference between high and low tide,  while other areas might have a massive 12 metres difference.

Roller Trailers;

For light dinghy trailer size, which is usually too short to offer buoyancy to your hull when launching, you use skids, and can push the boat off by hand.

There is no doubt that for any larger boat trailer, rollers may have some advantage especially if your ramp has low water.

May be not a full roller trailer but a combination of keel rollers and bunks is often ideal for most boats.

But there are considerations as cost and maintenance are more so with rollers although today rollers are only slightly more expensive than a bunk configuration, so  it is sometimes very economical to combine both.

Cost is associated with choice;

Replacing a steel trailer.

The problem with steel trailers is they rust…. They either die through rust, or the transport officials surprise you at the boat ramp and find your trailer to be unroadworthy or under sized for your boat...….. usually at a time when you are cash starved.

The obvious advantage of an aluminium trailer is they don’t rust and are lighter which gives you more payload and lower running tow costs in fuel.

Most medium to large Spitfire Trailers compete in price with a quality brand galvanised steel trailer and the pure bunk model is often cheaper.

Spitfire trailers are designed to be modular and can be configurered to suit your needs and budget.


Nothing to damage your boat

The pure bunk trailer is the cheapest version and  will get you out of trouble at the most efficient cost… and after you use it a few times... you might wonder why do people use rollers at all.

There is very little chance to damage your boat on a pure bunk trailer because there is nothing to bump into … even if you come on in tide run with wind blowing across you ….and if you have enough water to use it then it is a good, simple and practical trailer.

However trailers are like everything in life... a compromise.

Spitfire trailers offer one of the lowest   height entries of a boat trailers on the market,  which is ideal for launching in shallow water or beach launching.

However because the entry height is so low, on some shallow V hulls the mudguards and boat may contact.

To avoid this the mudguard height is adjustable on Spitfire’s  Latest Model range… and for very shallow hull Vs  Spitfire offer inexpensive keel rollers which can raise the height of the hull to clear the mudguards for shallow bottom boats 


What are the best materials for for rollers.

For side rollers,  Spitfire Rollers are made from three different materials…. almost like a wheel as in hub, rim and tyre.

The hard inner of the roller, similar to the hub of a wheel,  is made of PA which is a very hard and performs well against spindle / mini axle.

The main body, like the rim of a wheel  is made from PP which is also a hard and robust material.

The outer surface is made from EVA which is a soft material and won’t damage the finest fibreglass finish


Keel Rollers

Keel rollers can be either PA which is very hard strong material and ideal for rough aluminium keels, or they can be made of PU which is a slightly softer material and ideal for fibre glass keels.

Which is the better contact surface for Bunks… Carpet or Plastic ?

Carpet is a No … No.. No...and a left over from the 1970s.

Never ever use carpet bunks on fibre glass or aluminium hulls.

A very wise man once said;

Never believe anything you hear or read and only half of what you see.

Use your brain, to think for yourself and you will be a very wise man.

Carpet is very much in use today... but not on Spitfire trailers.

Carpet has three major problems.

1. On fibreglass boats, carpet causes osmosis.

2.Carpet collects sand and becomes sandpaper.

3. On aluminium boats Carpet accelerates corrosion through electrolysis. 

Let's look at these statements and think for your self, as to if you would want carpet bunks on your hull.


1. On fibreglass boats, carpet causes osmosis.

Osmosis it the cancer of fibre glass.

There are many technical descriptions of osmosis in relation to fibreglass.


A simple explanation is osmosis is the transfer of moisture through an almost waterproof material.

Fibreglass boats have a Gel Coat outer finish.

Gelcoat is water proof if you wash your boat, but with long term exposure to moisture, the  moisture will penetrate the Gel coat surface and cause a breakdown and chemical reaction to the resin holding the glass fibre.

At first it appears as blisters on the surface and seems an unsightly pity, however as it grows like a cancer it destroys the resin that holds the glass, blisters will ooze an oily like brown fluid and the once steel hard hull becomes soft and spongey with no integral strength.

It can be cut out and repaired but usually, like cancer, is not always successful.

Osmosis caused by carpet bunks.

Osmosis caused by carpet bunks.

Why do carpet bunks cause osmosis.

This is where you need to, not believe anything you hear or read and think for your self.

The reality of a carpet bunk is it comes out of  the water wet.... usually wet with salt water.

That would be good if it dried out… which it might the next day… but night fall comes and your boat gets covered in dew and the dew runs down the side of your boat and where does it stop… ?

On the carpet bunk.

Absorbed like water to a sponge.

Adding to this, if not thoroughly washed,  after use in salt water, and that is pretty impossible to do that with a boat sitting on it, the water dries and the salt remains and on any humid day, even without rain or dew the salt collects moisture from the air.

It would be OK if you lived at Alice Springs and there was dry air with no dew… but you have a boat and so you live near the coast and all costal areas enjoy dew…. Or in the case of Fibreglass boats and carpet bunks, suffer from dew.

Souther States like Tasmania, Victoria are bad because the cold winters keep the carpet wet longer

Tropical States like Queensland are worse because you have in addition to the dew, you have humidity, afternoon thunderstorms, and heat.

Southern Queensland gets most of it’s rainfall from December to February and in the far north you have the Monsoon Seasons from which can run from October to March.

This continual wet carpet either from dew,  rain,  salt crystal absorption keeping the carpet wet  is the cause of osmosis and will destroy a fibreglass hull.

The end result is very expensive.

Never ever use carpet bunks on fibreglass hulls.

2.Carpet collects sand and becomes sandpaper.

Again, do not believe anything you read on the web...Think about this and form your own opinion.

Boat ramps are usually very busy places on good boating days.

The water is shallow and with many boats using the ramp and the sand is churned up… or even if you are the only boat on that day, if you have bunks, then chances are you drive your boat off the trailer.

Think about what happens when you put your motor in reverse and back it off.

The prop is close to the ramp and stirs up sand off the ramp floor and swirls  it forward all over your bunks.

Drive your trailer to the car park and the water runs off and while you are boating and  the carpet dries… but the sand is caught in the fibres.

Do this 5 or 6 times and you have made the perfect carpet sandpaper to buff  the beautiful gel coat surface on your fibreglass hull.

Worse than that you have removed the glass finish surface and made it easier for water permeation to cause osmosis.

3. On aluminium boats Carpet accelerates corrosion through electrolysis. 

True carpet on aluminium is not as bad as carpet on glass, but it is still a No... No..

Todays aluminium boats come in two finishes.

Raw mill finish aluminium hulls…. or painted hulls on many smaller to mid size boats.

On the painted hull… simple… carpet bunks will just blister your paint from the continual moisture of dew, rain or humidity attracted by residue sale crystals.

The raw mill finish hulls will suffer a little more as most carpet bunks are on wood which is secured to different metals supports and this  might mean anything from or a combination of steel, galvanised, aluminium, stainless steel supports,  galvanised bolts or stainless steel staples and when your aluminium hull is in continual contact with different metals of different nobility and there is a conductive connection  fluid, as in a wet carpet bunk … then you are creating a battery which is called electrolysis.

Carpet bunks on an aluminium hull will cause corrosion and pitting as a result of electrolysis.

In simple terms, while many trailer manufactures see carpet bunks as a cheap alternative…Carpet  will wreck your boat,  be it fibreglass or aluminium.

Osmosis caused by carpet bunks.

Osmosis caused by carpet bunks.

Examples of plastic bunk

What is the best bunk material?

Any material that does not retain moisture.

Any form of solid plastic of various composition.

Trailer makers use a range of designs as can be seen above

At Spitfire Trailers we have had a long association with practical boating, much longer than half a century and we have seen and enjoyed and also suffered the evolution of boat trailers.

So we have designed what we think is the perfect bunk.

Somebody tomorrow will come up with a better idea, that is the evolution of life and progress, but we think at the moment, our bunk offers the best of technology and design at this time.

Spitfire Grooved PE Boat Trailer Bunks

Spitfire Trailer Bunks

Our bunks are a PE Grooved Cap…hard and shiny…..set on an angle... this helps protect the hull if hit side on in unfavourable loading conditions.

We have designed  it to allow it to dry and any dew or rain will run off.

Also the angled ridges and groves prevent sandpapering your hull as it is extremely unlikely that sand particles will rest on top of the rounded high contact spots.

If you have ever towed an empty boat trailer you will know they tend to bounce and any sand resting on the rounded high angled contact ridges  should fall into the groves when backing down to the boat ramp.

Will PE bunks damage my fibreglass hull ?

Generally speaking no.

Having said that, any two materials making contact under movement will wear to some degree.

A new shiny glass hull on new PA bunks on a correctly fitted trailer will show little, if any, wear.

Older fibreglass hulls oxidise and a white powder is present on most old hulls. 

This powder will show up on the bunks,  but this same powder would  rub off into a carpet bunk, but not be so noticeable.

Given the choice,  any material except carpet,  puts you ahead of very expensive damage.


What is the most common problem with boat trailers ?

Wheel Bearings....

Wheel bearings are far the most troubling issue.

The problem with wheel bearings on any brand of trailer is physics.

The problem is not the bearings or seals or the brand of them but  the expectations of the owner.

Spitfire trailers have a stainless steel bearing cap / buddy which allows the owner to easily inspect and re grease the bearings without removing the hub caps or bearings.

These stainless steel hub caps have a neoprene cap which when removed gives you a visual reference to the amount of grease in your hub and also allows you to top it up.


There is a  a spring loaded sight gauge that gives you  a visual check if the hub is full of grease or not so full.

It also has an external grease nipple, to easily keep the grease topped up without the need to remove the bearings.

The idea is to keep the indicator showing full.... that means the spring is compressed.

If the spring is compressed your hubs are full.... but full of what ?

SpitfireTtrailer outlets check this in pre delivery to make sure it is full of grease and not full of grease and air.

Axles and hubs are made by axle makers and sometimes there is a situation where they can get an air lock in the hub and it is not 100% full of grease.

In this case you drive your trailer and the hubs get hot... very hot... you back into cold seawater and the hubs rapidly cool and the result is the hot air inside the hub reduces in volume and creates a vacuum which sucks in water.

You enjoy your days boating and drive home the hubs get hot again and the grease and air seperate when you park your trailer, with the hot grease falling to the bottom of the hub and the air at the top.

The sudden cooling has sucked in water also and you would need a NASSA budget to pay for a wheel bearing seal kit that could resit the pressure change caused by  temperature drop from boiling hot to cold,  without the internal pressure reduction sucking water past the seal into the hub internal area.

Spitfire trailers also use marine seals... 

What is a marine seal ?

Well,  today almost all seals qualify as a marine seal.

Originally seals had one sealing ring.

Marine seals came out with two sealing rings, and others come as seperate concoctions of stainless and a form of rubber that rotate inside each other.

Almost all seals today have multiple sealing surfaces and could be called marine seals.

But the problem is not the seals.. it is physics.

Normal friction between spindles and hubs create heat and when you tow your trailer to the boat ramp the hubs get hot.

Braked axles get extremely hot.

The problem arises when you plunge a hot hub into cold water and no matter what seals you use they will fail.

We say to physically check your bearings every 6 months, and this is fine if you use your boat trailer regularly.

Water in grease is not ideal, but you can run hubs with water saturated grease for a very long time without major damage to the bearings.... if you use it regularly and if oxygen is not present.

The problem worsens if you have little grease, and it is contaminated with salt water and you don't use your trailer for several months.

Often we hear people say my bearings are gone, my trailer is only 6 months old and I have only put it in the water 3 times.

Lack of use allows the rust to form.

Another problem is people sometimes kill their seals with kindness and over grease.

A normal grease gun can create pressures of 7,000Psi.

Over pumping a grease gun can blow out the back seal which might not be noticed.

Several hundred Ks down the road the wheel falls off, or wobbles badly,  the seals and bearings are destroyed beyond recognition and the owner does not realise he destroyed the back seal with over pressure which allowed the grease to run out when hot.

Most seals and  hubs are designed to prevent this blow out,  but it is not a perfect world and  7,000 Psi is a lot of pressure.

There are a number of different wheel bearing / seal systems.

One is an oil filled hub.

 These work fine but are not popular as if they fail, that is the end of the journey. 

 The oil runs out instantly and you can not travel without bearings seizing.

The good thing about a conventional grease filled hub, which is the most popular in Australia because of our long distances,  is if it leaks there are  usually many warning signs over time.

An inspection inside the wheel rim will show if there is a spattering of grease and even if there is you can probably travel a few hundred Ks before it completely fails.


What is the most dangerous mistake trailer owners make ?

There is no doubt,  the most dangerous mistake boat trailer owners make, is incorrect fitting of the boat to the trailer which results in incorrect weight on the tow ball.

When you are hurtling along the highway at 100  Ks per hour with a ton or more of vehicle and 2 or 3n Ton of boat and trailer on the back, many forces come into play.

The wind from an oncoming semi... road surface undulation, braking, cornering all have effect on the dynamics of your combination of vehicle and trailer.

The tow ball weight is critical, in fact it is life threatening to both the driver, passengers and other road traffic, if not set correctly.

Centre of gravity is what controls ball weight.

Too much weight on the tow ball will raise the front wheels.

This might go unnoticed for years until one day you drive down a hill and the road is damp and on a bend you have no steering.

Not enough weight on the front wheels to control the steering of the towing vehicle.

Over the side of the mountain... or into an oncoming Semi... either is not healthy.

That is the effect of too much weight.

Far more dangerous is too little weight on the tow ball.

Too little weight for any number of outside forces such as passing an oncoming semi, braking, cross wind, can start your trailer fish tailing.

This is  a very  frightening experience as the trailer starts to control the towing vehicle and if not corrected immediately can result in fatal consequences to you the driver, passengers  and other road users.

The  accepted general rule is to have 10% of your total trailer and payload weight on the tow ball.


A trailer with a 2  Ton ATM ( trailer and payload including ball weight) should have 200 kg on the tow ball.

A 1,500 kg ATM should have 150kg on the ball.

We have a whole page dedicated to fitting and balancing your boat on your trailer.. check it out under The title on the menu  above "Correct fitting"


Check your tow bar plate... make sure your vehicle has the approved equipment to tow your trailer's capacity.


 An early 2000 Toyota Hi Lux 4WD 1 ton ute, with a factory fitted tow bar only has a capacity to tow 1,850kg and a ball weight of 185kg... it can not legally tow a trailer with an ATM load of 2 ton.

Later model cars have increased tow bar and ball capacity, some up to 4 tons... so check your vehicle.


What is the most common complaint Spitfire dealers get ?

Jockey Wheels.

Without any doubt..... Jockey Wheels.

Our Spitfire Jockey Wheels are the worst in the trailer industry... so we are told by some.

All Spitfire,  products and accessories are always under constant review to seek out the best quality we can source.

This does create some problems for us  sometimes, as  people do call up and say your website says Bla Bla... but my trailer does not have this.

Our website states, to the effect that  "Design is always changing and striving for perfection and buyers should check the product  before purchase to ensure that the product they are buying is what they think  it is."

But when it comes to Jockey wheels we get most complaints.

I mean our current jockey wheels are Hot Dipped Galvanised, they have a nice big red handle to "Fold them up before driving"  and an even nicer handle to "wind them up before driving."

But we still get complaints that the customer was just pushing his trailer by hand the the yoke bent.

The Yoke is 6mm galvanised steel and the wheel axle is a 16mm bolt holding the hot dip galvanised rim.... but they still bend.


Our Cleaning lady the other day said;

 "It is none of my business, but it seems strange that the people who complain about the Jockey wheels bending or breaking when they push the trailer by hand,  all seem to have no tread on the tyre... do you think may be they forgot to lift it up before driving to the boat ramp and it hit a few gutters, bounced along the road and hit the odd speed bump?"

We told her that customers would not make up stories ..... and it is better that she stick to cleaning and leave the management decisions to us.

Our policy is simple... first time you destroy it,  we will replace it for free and recommend you lift it up before travel... second time you buy a new one.



What is the second most common complaint about spitfire Trailers ?

Bloody Hell.... 

Our winch roller brackets.

We get the odd customer that  comes back with a bent winch roller bracket... 

He says... " Look Mate.. this bloody winch bracket bent!"

We ask him if he drove the boat onto the trailer at 100 Miles per hour and smashed into the winch post... ?  

" No.. No.... No way way mate...No Way...

"I was washing the boat down and noticed it was bent... ... I do recall I stopped a bit quick at the traffic lights... but no way I smashed into it at the ramp.... No way mate"

Our policy here is a bit like Jockey Wheels ... we understand life is a learning curve... First time a new winch roller bracket free..