A 5-meter RIB weighs between 315 and 350 kg from the factory. This seems light, but that figure is deceiving: with the engine, fuel, equipment, and the trailer itself, the actual combined weight is around or exceeds the 750 kg legal limit between a light trailer and a trailer with its own registration plate. Choosing the correct Gross Vehicle Weight Rating (GVWR) is the key decision, and it can be calculated in five minutes. Here’s the method and recommendations by boat type.
- Actual combined weight: factory hull + 30-50% for engine, fuel, and equipment. A 5m "350 kg" RIB weighs 550-650 kg ready to travel.
- Recommended trailer for 4-5 meters: single axle, GVWR of 750 to 1,300 kg depending on boat and engine.
- Up to 750 kg GVWR: no separate registration plate, no separate insurance, and no periodic vehicle inspection (ITV). Can be towed with a B license.
- Above 750 kg: requires an overrun brake, a red registration plate, its own insurance, and an ITV. This is worthwhile when the boat is very close to the limit.
- For marine use, demand a hot-dip galvanized chassis: each launch submerges the trailer in saltwater.
Direct answer: single axle and between 750 and 1,300 kg GVWR
For a 4 to 5-meter boat, the standard trailer is a single axle with a GVWR of 750 to 1,300 kg. The 750 kg unbraked version covers dinghies, light RIBs, and small fishing boats with moderate engines. The braked version of 1,000-1,300 kg covers boats with large engines, heavy fiberglass hulls, or a lot of equipment.
The choice between the two is decided by the scales, not by preference or budget. The typical mistake is to calculate using the hull's catalog weight and then discover, on the road or during a Civil Guard check, that the combined weight exceeds the trailer's legal GVWR. Let’s go through the correct calculation step-by-step.
How to calculate your boat's real weight (the catalog lies)
The weight published by the shipyard is for the bare hull: without engine, without battery, without fuel, and without equipment. The real navigable weight is 30-50% higher than the catalog weight. This is what you need to add up:
- Catalog hull: 250-350 kg for 4.5-5.2 m RIBs; 350-500 kg for open fiberglass boats.
- Outboard engine: a 60 HP weighs about 100 kg; a 100-115 HP, between 160 and 180 kg.
- Fuel: 70-100 liter tank full, 55-80 kg.
- Battery, anchoring, and equipment: anchor, chain, life jackets, cooler, and awning easily add 40-80 kg.
- The trailer itself: 150-250 kg unladen weight in this size.
Real example: 5m RIB (330 kg) + 100 HP outboard (165 kg) + fuel (60 kg) + equipment (50 kg) = 605 kg for the boat. With a trailer unladen weight of 180 kg, the combined weight is 785 kg. A trailer with a 750 kg GVWR would already be overloaded. The complete calculation mechanics are explained in GVWR and payload: how to calculate it without exceeding limits and without fines.
Table: recommended trailer for your 4-5 meter boat
| Boat Type | Typical Navigable Weight | Recommended Trailer | Brake |
|---|---|---|---|
| Inflatable boat 4-4.5 m with 25-40 HP | 300-450 kg | Single axle, GVWR 750 kg | Not necessary |
| RIB 4.5-5 m with 60 HP | 450-600 kg | Single axle, GVWR 750 kg | Not necessary |
| RIB 5-5.2 m with 100-115 HP | 600-750 kg | Single axle, GVWR 1,000-1,300 kg | Yes, overrun |
| Fiberglass open boat 4.5-5 m | 550-750 kg | Single axle, GVWR 1,000-1,300 kg | Yes, overrun |
| Fishing-pleasure boat 5 m with cabin | 650-850 kg | Single axle, GVWR 1,300 kg | Yes, overrun |
The safety rule: allow a 15-20% margin between actual weight and GVWR. A trailer at its limit suffers more during braking, bumps, and ramps, and doesn't accommodate the extra equipment that always ends up on board.
Less than 750 kg or more: what changes in paperwork and cost
A trailer up to 750 kg GVWR is the frictionless option: it uses the car's license plate, is covered by the vehicle's insurance, doesn't require periodic ITV, and can be towed with a standard B license. It only requires its technical inspection card and a legally approved tow hitch on the car.
Above 750 kg, the trailer becomes an independent vehicle: it needs its own red license plate, circulation permit, separate insurance, and an annual ITV after 10 years of the vehicle. This sounds like a bureaucratic burden, but for many 5-meter boats with large engines, it is the only legal and safe configuration, as it includes an overrun brake and enhanced stability.
With a B license, you can tow trailers weighing over 750 kg as long as the combined GVWR of the car and trailer does not exceed 3,500 kg. For a 5-meter boat with a mid-size SUV, a B license is more than sufficient in almost all cases.
Rollers or bunks: the detail that facilitates every launch
At this length, the support system is as important as the GVWR. Multi-roller trailers distribute the hull over dozens of pivoting rollers: the boat goes up and down with almost no effort and no travelift, ideal if you launch alone or change ramps frequently. Bunk trailers (bunk) support the boat on carpeted guides, which are simpler and more economical, perfect for boats that are launched infrequently.
For light RIBs and inflatables, tilting bunks work well. For fiberglass boats that are launched every week, a multi-roller system pays for itself in convenience. How to position the boat correctly is explained in how to correctly position the boat on the trailer.
And a non-negotiable requirement for marine use: a hot-dip galvanized, not painted, chassis. Every launch submerges the trailer in saltwater. 2mm galvanized steel lasts decades; painted 1.5mm steel starts to corrode in two or three seasons.
What 4-5 meter boat are you buying (and what suits you)
If you are still choosing a boat, the trailer should be part of the equation from the beginning. A trailerable boat eliminates mooring costs and its 150-350 euros per month, and at this length, all boats are trailerable with a normal car. A comparison of models can be found in best trailerable RIBs from 5 to 7 meters.
To get the complete package right (boat, car, hitch, and trailer), the guide to choosing the perfect trailer for your boat covers all decisions in order. The summary: first weigh, then measure the total beam and length, and only then choose a model.
The car and the hitch: the other half of the equation
Before signing for the trailer, open your car's technical data sheet and look for the maximum towing capacity. A mid-size compact car can tow between 1,200 and 1,500 kg with a braked trailer and about 600-750 kg unbraked. An SUV or diesel family car can go up to 1,800-2,500 kg. For an 800 kg combined weight, almost any car with a hitch will work; for 1,200 kg, check the data first.
A tow hitch is a legally recognized modification: it must be installed by a workshop and noted on the car's technical data sheet at the next inspection. It costs between 300 and 700 euros installed depending on the model and type (fixed, removable, or retractable). Add the 13-pin electrical connection, which is most recommended for marine use because it powers the trailer lights with a watertight connection.
A driving detail: with a trailer, the speed limit on highways drops to 90 km/h, and braking distance increases. At this length, the combination is barely noticeable behind the car, but the first wet ramp demands respect: four-wheel drive or a smooth start in first gear.
The three most expensive mistakes at this length
The first is buying a trailer with a GVWR that is just enough. The boat gains weight over the years: auxiliary engine, awning, cooler, second battery. That 15-20% margin that seems exaggerated today is what prevents you from having to change trailers in three seasons.
The second is saving on chassis treatment. In marine environments, the trailer is submerged with each launch, and a painted chassis corrodes from inside the profiles, where it's not visible. When external rust appears, the structural damage is already done. Hot-dip galvanizing costs little more and lasts for decades.
The third is forgetting the beam. A 4-5 meter boat usually measures 1.9-2.3 meters in beam, which is within the legal width without special signaling. But some models with floatation tubes or wide fenders exceed this: measure before buying, because the beam is as important as the weight in choosing the model.
Where to find the exact trailer for 4-5 meters
The range of boat trailers covers this length with single-axle models starting from 750 kg GVWR, hot-dip galvanized chassis, and 2mm steel compared to the standard 1.5mm. These are among the lightest trailers in their class on the market, which leaves more payload margin for your boat with the same GVWR.
If your vessel is a speed boat or a RIB with a large engine, check the trailers for speed boats, with braked versions of 1,000-1,300 kg. And if the boat grows in the future, the range of nautical trailers extends up to 12 meters in length.
All are delivered with European homologation, complete documentation, and a 2-year warranty, purchased directly without intermediaries. Arnaud will confirm over a call which GVWR and roller configuration fits your exact boat: consult without obligation. If you are unsure about the next length step, the 6-meter boat trailer is the best-selling reference.
Frequently Asked Questions
What kind of trailer do I need for a 5-meter RIB?
A single-axle trailer. With an engine up to 60 HP and moderate equipment, a 750 kg GVWR is usually sufficient. With a 100-115 HP engine, the actual combined boat weight is around 600-750 kg, and a braked trailer with a 1,000-1,300 kg GVWR and a safety margin is advisable.
Can I tow a 5-meter boat with a B license?
Yes. With a trailer up to 750 kg GVWR, there are no added restrictions. With a larger trailer, a B license is sufficient as long as the combined GVWR of the car plus trailer does not exceed 3,500 kg, which covers almost any combination of a 5-meter boat and a mid-size SUV.
Does my boat trailer need its own registration plate and insurance?
It depends on the trailer's GVWR. Up to 750 kg, it uses the car's plate and insurance. Above that, it requires its own red registration plate, circulation permit, separate insurance, and periodic technical inspection. In both cases, it must have its own technical inspection card.
Braked or unbraked trailer for a 4-5 meter boat?
Unbraked up to 750 kg GVWR, which covers inflatables and RIBs with small engines. With an overrun brake from that point onwards. If your actual combined weight is around 700 kg, consider upgrading to the braked version: it brakes better and suffers less wear, and gives you margin for the equipment you will gradually add.
How much does a 5-meter boat really weigh when ready to tow?
Between 550 and 800 kg in most cases: hull (300-500 kg), engine (100-180 kg), fuel (50-80 kg), and equipment (40-80 kg). Add the trailer's unladen weight (150-250 kg) to find the combined weight your car will tow and compare it to its maximum towing capacity.
What maintenance does a nautical trailer of this size need?
Little but constant: washing with fresh water after each launch, greasing the hub, and annual inspection of lights and tie-downs. The decisive factor is from the factory: a hot-dip galvanized chassis resists saltwater for decades, while a painted one corrodes in a few seasons.
How much does a trailer for a 4-5 meter boat cost?
A new single-axle nautical trailer with a 750 kg GVWR starts at about 1,000-1,500 euros with a galvanized chassis; braked versions of 1,000-1,300 kg go up to 1,500-2,500 euros. By buying directly from the distributor without intermediaries, the same equipment costs 15-50% less than at a multi-brand store.
Does the same trailer work for an inflatable and a RIB?
Yes, if the weight and beam fit and the support system is adjusted. Tilting supports and rollers are adjustable in height and width to adapt to different hulls. Verify the position of the bow support and weight distribution: the tongue should carry between 5 and 10% of the total weight.
How fast can I drive with the boat on the trailer?
With a trailer, the general speed limit is 90 km/h on motorways and dual carriageways and 80 km/h on conventional roads. In addition to the legal limit, the practical rule in boating is not to exceed the speed at which the combination remains stable: if swaying occurs, progressively reduce speed without harsh braking and at the next stop, check the weight distribution on the tongue, because a boat positioned too far back on the trailer is the most common cause of such swaying.
