Picking up where we left off in my last posting, if you take too much of an angle to the waves and/or find yourself perpendicular to them, then you are operating in a "Beam Sea".

In a beam sea, you can actually operate at a pretty fast speed. Just be absolutely certain to keep an eye out for breaking waves and either increasing or decreasing your speed accordingly steering for clearer water behind the breaking wave. Breaking waves can be very dangerous and can easily capsize a boat if the operator is not paying attention.

If you find yourself unable to escape a breaking wave you have a couple options. You can turn into and ride it much as I described for a "Head Sea" or turn away from it and run in front of it. Doing this seems to make sense, but it could also be much more dangerous unless you can be sure you can out run the amazing speed these waves can reach.

Going with the waves brings us to the next type of sea condition, the Following Sea or heading down wind (going in the direction of the wind/ waves). Traveling in a following sea can be quite deceiving and seem very comfortable as you will be traveling the same direction as the wind and waves which results in a very calm feeling. However, it can be extremely dangerous should a breaking wave catch the RIB from behind. If it does, there's potential the wave can turn the boat sideways to the waves which could set the boat up for a capsize at the next one.

Waves can move surprisingly fast, up to almost 30 knots, which means that your speed through the water could be very low. For example, if you're moving at 20 knots and the waves are traveling at 18 knots, your actual speed through the water is only 2 knots. If you add this low speed to the prop having problems getting any clean water to bight into in the churned and confused water from breaking waves, steering can be rendered virtually useless. This is one reason why it's important to insure your RIB has adequate power before venturing out in rough conditions so that you have the needed power to outrun the waves.

The way to operate in a following sea, is to ride the wave by staying behind the crest or break. As it begins to break, power up so that you sit on the back of the next wave. Whenever running in a following sea, it is essential that you keep a vigilant look out behind so that a wave doesn't catch up and surprise you. Be careful, because you're not always going to feel like you're moving very fast in a following sea, but you potentially will be, so you want to be careful not to power through the breaking wave too early as it's easy to launch off the crest of the wave into the giant hole on the other side and dive into the back of the next wave – stuffing the bow.

When this happens, a dramatic loss of speed results which leaves the boat exposed to the waves from behind again. Also, if the boat stuffs, there's a good chance those on board will be tossed forward and the boat will be filled with water.

Portions of the above advice were excerpted from RIB International (Dec/Jan 06/07)

Posted by ribcraftusa at 07:30 PM | Permalink | Comments (5)

When driving in rough water, the most important thing to do is to match your speed and direction to the water conditions through adjusting your throttle and steering accordingly. Though it may be a blast to keep the throttle on and wave jump, eventually you and the boat will get tired of it. Just as important however, if the prop is continuously leaving and re-entering the water the efficiency of the boat to make quick headway is greatly reduced.

There are several conditions that operators need to know how to handle. The first is driving upwind to weather or in a "Head Sea".

To do this it's important to first be sure your trim is adjusted all the way down in order to keep the bow down. This will minimize the amount of lift off the wave but also promote the best entry through the water which promotes optimal performance of the V hull to cut through the water.

Long Wavelengths

Now, if you're driving in very large waves with some distance between them (distance between waves = wavelength) I've outlined some helpful tips. Once your trim is adjusted, you want to approach each wave so that you are driving up the face of it carefully easing off on the throttle as you approach to the top so as to not launch off the crest or top. Then, drive down the wave speeding up so that the bow will raise as the next wave approaches.

As you do this, you'll find the ride to be pretty fast and amazingly smooth. Driving into a head sea is actually all about throttling ON and OFF as you make your way through the waves.

Short Wavelengths

With shorter wavelengths or short sharper chop the above method can prove almost impossible to accomplish so try using what I call the "Sailing Method" where you literally "Tack" upwind by driving the RIB at 30º to 45º to the waves. What this does is increase the perceived wavelength which allows the operator to adjust the throttle as described above. Though this will add distance to your trip the improved comfort and safety will be well worth it.

Posted by ribcraftusa at 10:49 AM | Permalink | Comments (5)

The combination of the deep V hull and the inflatable tube give a RIB its outstanding sea-keeping abilities. The tube acts like a giant shock absorber absorbing most of the impact forces thus reducing the stress on the boat and crew. Additionally, the tube contributes to a far more stable ride than other types of boats by significantly reducing any lateral movement. This allows a RIB to carry a deeper V hull than hardsided boats which contributes to a smoother ride in rough conditions. Not only does a RIB handle seas way beyond what other types of boats of its length could handle, it's far less likely to take on water. And, if it does, a RIB doesn't trap it and has the ability to get rid of the water quickly if necessary through a low transom and high capacity deck drains. What's more, with the incredible buoyancy provided by the tube a RIB is far more capable of supporting large amounts of water on deck without sacrificing stability.

All of these qualities describe a Really Incredible Boat (RIB)!

Posted by ribcraftusa at 04:51 PM | Permalink | Comments (0)