What Is A Transom On A Boat?

A transom on a boat (or boat transom) is the vertical area at the back of the boat.

The back of the boat is also known as the rear, at least in nautical terms, and can be thought of as the palace where the hard work happens.

Typically a transom will be home to the outboard motor.

There may even be more than one motor in the transom. 

If you happen to have a new center console or offshore boat then you may find that your transom also has a rear door.

This often leads to a swim platform which you can jump off into the sea.

There may also be a set back bracket that is molded or bolted on.

On some boats, the transom may also be there as a means of supporting the rudder. 

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The shape, height, and overall appearance of the transom depend on the particular boat.

You may find that some boats display the name of the craft on the transom as well as on the sides. 

The purpose of a transom was originally to strengthen the stern of the boat.

Typically it is a flat termination and rests on the stern above the waterline.

The name of it ‘transom’ is thought to have originated from the Latin word for transverse.

This was transversus.

Transversus was, in turn, thought to have originated from an Old French word for the phrase ‘set crosswise’.

This was ‘Traversain’. 

Of course, given what we know the transom to be, it makes sense that these are the origins given the shape and structure it has.

It is thought to have been a word that has been in use since the 1300s! 

One thing is for sure and that is that the transom is an integral part of the boat, whether it is used for the rudder, the outboard motor, or even as a simple swimming platform or access area. 

What is a transom on a boat

How do I know if my boat transom is bad?

The best way of telling whether your transom is bad is by looking for physical signs that it has deteriorated.

As it is a piece of hardware that is visible whilst you are on or sound the boat, you can easily see if there are any visible signs of damage by investigating it for cracks.

You can also inspect it for any other damage such as signs of wear, and bumps and scratches, and anything else that looks as though it may be causing an issue. 

Typically a transom is made from plywood and features outer layers made from the likes of fiberglass, plastic, and other durable coatings.

However, plywood does not last forever and is not known to be the most sturdy material out there.

As such, it is not uncommon to find that the plywood has weakened, becoming flexible and even rotten over time.

This can then, in turn, affect the outer coatings.

Likewise, the opposite can happen where the sturdy outer layers made from plastic and fiberglass get damaged, thus causing the plywood to wear down quickly.

When this happens it is a sure sign that the transom has gone bad (or is at risk of it) and you should deal with it accordingly. 

Can a boat transom be repaired?

You can repair a boat transom, especially if there are just some surface cracks.

Provided the cracks are only on the outside layers and cannot let masses of water into the plywood, then these can be fixed easily by applying a substance that will adequately seal the crack or hole.

The sealant should be durable enough to keep water out of the hole so that it cannot reach the core. 

However, if the issue is inside the transom, in the plywood, then this can be far trickier.

The likelihood is that if there is damage that goes through the plywood then the plywood has already been in contact with water and so it may have weakened already.

In this case, it is often best to just replace the transom as it will be easier and may even be cheaper. 

How long does a boat transom last?

A good quality boat ransom can last around 20 years or so, provided it is looked after properly and checked regularly for cracks.

Any surface cracks that you notice should be dealt with swiftly and properly.

Apply a durable, waterproof sealant to ensure that water cannot seep in and potentially reach the plywood core.

Provided you follow these instructions, you should be able to get 20 years at a maximum from your boat transom. 

Of course, if the transom is used often for a swimming board or access route then it may not last this long as it will be in constant use by people.

This may mean that you need to undertake even more upkeep and may mean it needs to be replaced a little quicker. 

That being said, you may find that the transom is used only as a place for the outboard motor or rudder.

As such, the transom does not get any human interaction for things such as swimming where it holds weight for some time.

If this is the case then you can expect it to last a little longer, as long as you take care of it. 

How do you stop transom rot?

Transom rot is simply wood rot.

The best (and indeed only) way to get rid of wood rot is to take out the rotten pieces of wood and any other pieces that are in contact with it.

Fixing a rotten transom can be a tricky business since the plywood is in the core of the transom rather than an easy-to-reach outer surface.

That being said, it can happen, and so if you do decide to tackle the wood rot head-on by taking it out and replacing it with fresh wood, you should ensure you get every last bit, as well as making sure any cracks are sealed up to prevent it from happening again.

You may feel that it would be easier to just replace the transom completely.