Speed and safety

Finding the right balance

 

Finding the right balance between speed and safety is something not even the most experienced driver should ever become complacent about. So how can you be confident you’re getting it right?  Rachel Andrews, RYA Chief Instructor, Motor Cruising and Power shares some sound advice on finding the balance.  

Back to Basics

Cast your mind back to your Powerboat Level 2 (PB2).  

Everyone with PB2 should know that ‘safe speed’ is one of the fundamental rules of the road under the International Rules for the Prevention of Collisions at Sea (IRPCS) or Collision Regulations (COLREGS) as they are more commonly known.

Yet ‘safe speed’ does not always mean slow, but driving to the conditions.

Meanwhile, the importance of wearing your kill cord was highlighted by the tragic events that unfolded on board the RIB Milly in the Camel Estuary in 2013.

Basic balance and trimming your boat are key components of PB2 with the critical concepts of fore and aft trim (raising and lowering the bow) and side-to-side trim (levelling the boat if it’s leaning to one side) introduced.

Where passengers and kit in the boat should be positioned for trimming and safety purposes is also addressed, along with reinforcing the understanding that trim needs constant adjustment to remain safe and to maximise the boat’s performance.

Checking the trim if crew or passengers move around the boat, there is a change in sea conditions or water comes aboard is just common sense right?

Yet you might be surprised that common sense stops being so common if, for example, someone has not driven for a while, is driving an unfamiliar boat or is experiencing conditions or circumstances new to them.

Understanding the theory is one thing, being able to apply the principles in all situations is another in making higher speed driving safe and fun.

Turning the tables

Have you heard of ‘hooking’? Although the term has been familiar to powerboat racers for many years, hooking is still something of an unknown amongst recreational boaters.

The consequences of hooking, however, can be catastrophic.

Put simply, hooking is when a boat is travelling at speed and, sometimes for no obvious reason, the nose digs in to the water and grips, causing a sudden deceleration, the back end loses grip and slides, and, as a result, the boat violently pulls round to port or starboard, possibly throwing everyone out of the boat.

The ‘hook’ is the uncontrollable spin, and although most typically it will occur during high-speed turns, it can happen when travelling in a straight line too.

Hooking is something powerboat racers will try to avoid at all costs. The nature of racing means boats are likely to be fairly well matched, racing closely together in the same direction around a circuit.

However, when boats are racing on the edge, most commonly trying to gain an advantage going around a mark, it’s inevitable a hook may occur at some time. The skill is minimising the likelihood and its effect.

In leisure boating, hooking is much rarer. Yet what happened in Padstow brought to attention that it is a risk and recreational boaters do need to be aware of the dangers of suddenly changing direction at high speeds.

Part of the MAIB report into the Padstow incident noted:   “When executing the turns, the craft initially would take up a high-heel angle. It would proceed to turn, but if the speed was slightly higher than a particular threshold and the turn tighter than a certain degree, the heel angle would increase during the turn, and the aft end would lose grip and slide – thus initiating a ‘partial spin’ or ‘hook’ since the bow did not slide by the same amount.

 “This rapidly took the craft to a position, which was appreciably diverted from its original course. The craft would execute a sideways slide and grip suddenly when it landed. Thus the hull’s sideways motion was suddenly stopped.”

Hooking is not demonstrated during an RYA training course due to the extreme forces exerted on the crew, and the possibility of sustaining injuries.

The RYA Powerboat Scheme courses are about teaching people to drive boats sensibly and with respectful confidence. Drivers are taught to trim down before commencing a high-speed turn for greater grip and control during the turn and to consider boat load plus the importance of communication and holding on.

Yet it’s naïve to think recreational boaters won’t, at some point, push their vessels to the extreme. That is why powerboat instructors are highlighting the differences in helming a more powerful boat while also talking a little more about loss of grip during tight turns, reiterating why you should always wear your kill cord.

Hull of a ride

The shape of your hull will have an impact of the top end speed of your boat.

Some hulls, such as a displacement or semi-displacement hull, will never be able to plane on top of the water. Traditional ‘V’ shaped hulls are good in waves and rougher conditions as the deeper the ‘V’ the better it is at cutting through waves.

One of the most popular hull shapes now being found on leisure craft are stepped hulls. These were originally developed for racing but have been adapted for recreational boats because there is less contact with the water and less resistance, enabling the thrill of planing and a more exciting ride. They use less fuel too.  

However, because they ride higher in the water with less grip, in turns stepped hull designs can behave less predictably than other hull types.  

Getting the trim right in a stepped hull, understanding care should be taken not to trim too far nor to reduce power suddenly in the turn, plus knowing where to put the boat in the waves and wash, are all important in avoiding hooking or swamping.  

Balancing act

The relationship between balance and speed is clear - the better trimmed your boat, the greater performance and fuel conservation you will get from it, while an unbalanced boat can pose a risk to safety especially when travelling at high speed.  

The basic rule is put any kit and equipment, whether that is a cool-box or spare fuel tank, where you want it before you set off, and tie it down, as if it moves when the boat is unstable the shift of weight could exacerbate an incident considerably.  

The placement of people is just as important.    

When the boat is being driven at higher speeds, skippers should be mindful of having passengers ‘loose’ at the front where forces are more exaggerated. This will also impact on the boat’s centre of gravity and balance.  

Anyone who transports families or groups of people around, for example superyacht crews transferring families on tenders, need to be aware of this, and will need to helm accordingly, which may mean more slowly.  

Another factor effecting balance is water coming on to the boat. It’s easy to underestimate how the smallest amounts of water pooling on deck or in the foot-well or cockpit can quickly escalate into a bigger problem.  

There are two things to consider here:

  1. Preventing water coming aboard in the first place
  2. How to react effectively should it start building up  

If, for example, you are travelling in a following sea with the waves behind you, you should have the boat trimmed front up, while adjusting your speed accordingly, so you don’t slide down the wave and swamp the boat over the bow. Going too slowly may also upset the ‘side-to-side’ balance of the boat as waves come over the back.  

Remember water will move to the lowest point, which can cause extreme instability, possibly contributing to a capsize, if it keeps building up. Don’t use passengers to balance the boat in this situation as the water will follow them to the lowest side with potentially the same outcome.  

You should know the water freeing arrangements on the boat you are driving as it can be different on all boats.  

Some will be fitted with automatic electric bilge pumps astern, others will have an ‘elephant’s trunk’ hose running out of a hole on the transom. This is generally pulled up when stationary but remember to let the string out when the boat is going along so any water coming aboard can run straight out the back.   

If a small amount of water has built up make sure the drain plug in the transom is open and clear and accelerate forwards to force the water out of the back.  

You can’t have safe speed without balance and vice versa. Understanding the relationship between the two and identifying potential risks will provide a much more enjoyable, comfortable and safe ride for everyone aboard.  

Find out more about RYA Powerboat Training