Guide to New Ribs

Introduction

In very simple terms, ribs sold and used in the UK can be broadly grouped into approximately four different size categories.

Whilst these are very approximate size categories – which could be subject to endless debate by purists and enthusiasts - we hope that these descriptions of the rib sizes will give those new to the water a good starting point for thinking about a new rib.
 

  • Small - 2.5m to 4m
  • Medium - 4m to 5m
  • Large - 5m to 7m
  • Very large - 7m upwards

Small Ribs – up to 4m long

A number of manufacturers make the smaller ribs. These small ribs are normally considered to be from 2.5m long to 4m.

These are inevitably used close inshore on the sea, or inland on lakes, reservoirs and lochs. These small ribs are simply not suitable for coastal or ocean work.

When used inshore and in sheltered sea conditions, these smaller ribs are quick and fast for short journeys in calmer sea conditions. When used on calmer inland lakes and lochs, these small ribs are easily capable of longer-ranging expeditions.

Good examples of these smaller ribs are the Zodiac Cadet Rib range, the smaller models in the more luxurious Zodiac Yachtline DL range and the Ribeye “TL” series.

These very small ribs will have a shallow V-hull, a low freeboard and may or may not have internal seating. The seating types (if fitted) are almost invariably either a single or twin jockey seat, or a small bench and low steering console. This is simply because there is not space for a larger console.

Where the small rib has no seating and console, the outboard engine choices on these small ribs will be a simple tiller steering outboard engine. However a small rib fitted with a mini console will have simple remote-controlled engine, which is controlled from the console mounted steering wheel.

Typically outboard engine sizes on these smallest ribs will be 15hp to 25hp, up to around 30 to 40 hp maximum.

Small ribs - especially when fitted with the seating and davit lifting points - are very popular as tenders on motor cruisers and larger yachts. These small ribs allow big boat owners the freedom to independently explore shallower areas, whilst still acting as a comfortable tender when in harbour or lying on a swinging mooring.

These smaller ribs are often left on a pontoon or mooring and thus permanently in the water.

Alternatively a boater can use a simple small road trailer, which allows these small ribs to be towed behind any small car. Launching of a small rib from a road trailer can be by one or two persons - often launching and recovery can be done by one person unaided (after a bit of practice).

Small ribs are not generally accessorised with electronic and navigation equipment, simply due to space constraints and the fact that the trips these smaller ribs will undertake will be “by line of sight” navigation boats. However simple VHF radios, chartplotters and fish-finders can all be fitted to small rib consoles.

These smaller ribs are often overlooked in internet and magazine reviews. However for simple family friendly boating and as yacht tenders these small ribs remain incredibly popular, very simple to use and are also great value.

Medium  Ribs - 4m to 5m

A number of manufacturers make these medium sized ribs, which are normally considered to be from 4m long to 5m. There is a good choice of sizes and shapes, all of which allow sea going capability.

Medium sized ribs can be used for all serious ribbing, club support, and general family friendly boating. They are especially good for all types of watersports.

It is in this medium rib size sector that the rib revolution started in the 1990’s, simply because ribs of this size offer a user a great deal of capability and capacity at a relatively economical cost. These medium ribs are therefore extremely common in the UK and ever- popular with a wide range of users.

These medium ribs will have a V-hull, quite a high freeboard and some internal seating. The seating types specified for medium ribs are almost invariably either a single/ twin jockey seat with an integrated console, or a small family friendly bench and separate console. Occasionally a stand up console and bolster seat are specified.

In inshore and coastal sea conditions these medium sized ribs are extremely capable, easily capable of tackling quite rough sea conditions, including higher waves and winds of up to force 6.

On calmer estuaries, sheltered sea areas, larger lakes and lochs these small ribs are capable of very long ranging expeditions.

The typical capacity of a medium rib is up to six persons, which makes them popular and very versatile either as family leisure boat, a typical “club type” support/ rescue ribs and as workboats for harbour and patrol use.

Engine choices on these medium ribs will always be a remote-controlled engine, steered from the helmsman’s console. Typical engine sizes will be from 30hp up to about 60 to 70hp maximum.

These medium ribs are either left on the water in a marina, or a boater can use a roller bed road trailer for launching and recovery.

The medium sized ribs are always popular trailer ribs, as their size and weight makes them easy to tow, launch and recover. The road trailer will to allow these medium sized ribs to be towed behind a larger saloon car, estate car or any 4x4. They can be trailer launched from any suitable slipway. This flexibility has made these ribs very popular to trail.

Most ribs under 5m can be stored in the average domestic garage.

Medium sized ribs are extremely versatile for allowing electronics fitments. These ribs can either be used “bare”, or accessorised with quite a large quantity of electronic and navigation equipment.

However just fitting simple VHF/DSC radios, smaller chart-plotters, depth sounders and fish-finders are a very popular choice.

During the boom years of the “noughies” these medium sized ribs were often overlooked in rib magazine reviews. However the medium sized rib in the 4m to 5m sector remains a classic design - incredibly popular, easy and simple to use and strong value for money.

Larger Ribs - 5m to 7m

A number of manufacturers make these larger ribs, which are normally considered to be from 5m long up to 7m.

Ribs of this size are often a broadly similar design to the medium sized ribs described above, often being the larger and more sophisticated models in the same manufacturers product and model ranges. 

Good examples of these larger ribs are the top end models in the Zodiac Pro rib range, the Zodiac Pro Open range larger, and the luxurious Zodiac Medline range, smaller models of the Zodiac N-Zo range and many of the Ribeyes.
However - when compared with the superficially similar medium sized ribs - the increased size of these large ribs offers a rib owner significantly more capability and capacity.

The improved capability and performance on these larger ribs for three technical reasons;
 

  • The greatly increased engine power.
  • Much improved sea-keeping capabilities.
  • The significant increase in deck space.

These larger ribs are therefore extremely common and popular with two types of rib users. Firstly they are used by the groups who need more space and power. dly or those who are trading up to allow them to undertake more serious expeditions and also to give an all weather capability.

These larger ribs will have a deep V-hull, high freeboards and generous internal seating. The seating types are extremely flexible, jockey seats behind a console, or bench seats and bolster seat.

The consoles on larger ribs are often the stand-up consoles.

Inshore these larger ribs are extremely capable, easily capable of tackling rough sea conditions. Most large ribs are rated for class “B” coastal waters (sometimes with operating restrictions) and therefore these larger ribs are capable of very much longer ranging expeditions in far more extreme weather conditions than medium sized ribs.

The typical load carrying capacity of a medium rib is up to 10 or 12 persons.  This makes them popular and very versatile with large family groups, expedition cruises and diving clubs.

Engine choices on these larger ribs will always be remote -controlled engines, steered from the helmsman’s console. Typical engine sizes will be over 100hp, often with engines up to the 250hp. Hydraulic steering is essential on almost all larger ribs.

The road trailer option will allow these larger ribs to be towed behind a larger estate car or, more commonly a 4x4.  They can be launched from any suitable large slipway. This flexibility has made them popular to trail.

However the size of these ribs of between 5m and 7m means that more people are needed for launching and recovery, which often means they are launched and then moored, rather than recovered after every short trip. 

Large ribs normally have large consoles with screens and this feature allows the rib owner to specify from a wide range of electronics and navigation equipment. Large ribs of this size are rarely used “bare”, as the ribs performance and range capability means that for an owner to fully utilise the ribs performance and range out of sight of land the rib needs to be accessorised with a variety of  electronic and navigation equipment, for both navigational and safety functions.

The longer range VHF/DSC radios, more sophisticated chart-plotters with integrated depth sounders and fish-finders are all very popular, almost necessary, choice on larger ribs.

Radars, AIS and EPRIBS are common on the top-end larger ribs, especially those used in all weathers.

Very Large Ribs – above 7m

Relatively few manufacturers make these larger ribs, which are normally considered to be above 7m. These larger ribs all feature have deep V-hulls, massive outboards, very high freeboards and generous deck areas. Many ribs of over 7m long have a commercial or military heritage.

 Good examples of these smaller ribs are the top end models in the Zodiac N-Zo rib range - both cabin ribs and dayboats - the luxury Zodiac Sea Hawk ribs and Medline and the larger Ribeyes.

At this size of rib there is considerable crossover between the leisure rib models with the rib manufacturers professional, commercial and even military rib ranges. The largest leisure ribs are often based on, or the designs developed from, commercial all-weather rib hulls. The use of the commercial hulls give better sea-keeping and wave riding, these ribs simply cut through all but the largest waves.

Ribs of this size are considerably larger and more sophisticated models, which will often be distinguished and highlighted as “flagships” in the manufacturer’s product and model ranges.

Relatively few very large ribs are sold in the UK, however these very large ribs feature prominently both at boat shows and in magazine reviews. Therefore large ribs have a profile in the rib market well above the relatively small numbers that are actually used in the UK.

The size and power of these very larger ribs gives the boater a performance and capability which is often beyond the capability and requirements of most leisure rib owners.

The significant increase in deck space - by both the rib length and the wider beam - gives the very large rib owner a vast amount of deck area to use.

These very larger ribs are therefore extremely popular with three types of rib users;
 

  • Smaller groups needing serious expedition capability and in particular all-weather capability
  • Commercial touring rib and rib wildlife safari operators
  • Larger rib dive boats

Given the large space on deck, the seating arrangements can be extremely flexible. Multiple jockey seats behind a wide console, or luxurious bench seats remain popular. The consoles on larger ribs are often the stand-up type.

Used inshore these larger ribs are extremely capable, easily capable of tackling all sea conditions. Almost all very large ribs are rated for class “B” coastal waters (occasionally with operating restrictions) and many are classified as suitable for commercial use.

Therefore these very large ribs are capable of very much longer ranging expeditions and in far more extreme sea and weather conditions. The typical capacity of a very large rib in inshore areas is up to twenty. This size makes them popular and very versatile with large family groups, expedition cruises rib tours and diving clubs.

Engine choices on these largest rib will be remote-controlled engine, steered from the helmsman’s console. Typical engine sizes will either be twin installations of a pair of outboards each of over 100hp, or single outboard over 200hp (often seen with up to the 350hp maximum). Hydraulic steering is essential.

These larger ribs can be used with a double-axle braked road trailer. However the large size and weight of the towing load demands a larger 4x4 to tow them. There are often driver’s license restrictions (or the vehicles insurance company’s requirements) that may well require the towing vehicles driver to have additional qualifications. 

These very large ribs can be launched only from the larger slipways. This requirement is often simply because of the large turning space that is needed for the vehicle and trailer to turn on the landward side of the slipway. The size of these all these ribs of over 7m means that a group of people is needed for safe launching and recovery.

The flexibility of the largest ribs still makes them popular to trail to a destination, however once launched normal practice is to then leave on a pontoon (or mooring) for the duration of the holiday or longer period of use.
The large ribs are inevitably fitted with longer range VHF/DSC radios, more sophisticated chart-plotters, integrated depth sounders and fish-finders. These electronics are simply essential on these larger ribs.

Radars, AIS, life-rafts and EPRIBS are also extremely common on these top end larger ribs, especially those used in all- weathers (and these items of safety equipment are often mandatory on vessels used for commercial purposes).