Self-rescue ladder D4S

UNDER CONSTRUCTION

Design & Engineering: Design 4 Sea.

Figure 1. Self-rescue ladder D4S (model DE4H).

A life-saving device for single-handed and short-handed crew.

Against intuition, in most of the cases, you cannot climb aboard alone after falling overboard even if you wear harness and tether.

In addition, without adequate equipment and training, it is very difficult for a single person to lift you aboard. People die along their hull every year. See study by the Seattle Sailing Foundation, 1999 (pdf).

We have lived this experience, two of us hanging overboard by our tethers and unable to climb (breaking waves, wet clothes, broken lifelines, broken aft ladder...). So we designed this self-rescue ladder.

Solution: a portable ladder and hanging ropes to climb aboard

If the boat is underway, no way to detach yourself, so you have to climb aboard wherever you are. Forget about emergency ladders at the stern!

If the hull is high, the boat is provided with clipping points reachable from the water.

Clip the ladder as high as you can, unfold it and climb. If this is too acrobatic, use a self-rescue tether.

Figure 2. Self-rescue ladder deployed (model DE4H)

In more details

The ladder is packed in a tubular sleeve. Pull the sleeve to deploy the ladder.

Figure 3. Pulling out the ladder. Right: detail of the snaphook (model DE4H).

The ladder has several steps (or stirrups) that look like inverted "T"s (Fig.4). The stirrups are closed by means of elastic strap, in order to prevent tangling.

Pull on the stirrup to open it wide, then place the foot in it.

a

Figure 4. Opening the stirrups (model DE3H).

The stirrups are independent, their ropes are just braided together to avoid tangling. Independent stirrups are easier to manipulate and less unstable than a classical rope ladder.

The ladder normally fits in your pocket (weight ~100g, dimension ~23cm x 2cm) , fixed on the harness (scratch) and/or form part of the tether (see self-rescue tether).

Figure 5. Wearing a self-rescue ladder (model DE3H).

Miscellaneous. There is a safety rope (otherwise the ladder could be lost in the water). The sleeve is attached to the last step. It is weighted in order to prevent tangling.

Clipping points

On low boats, the ladder can be clipped to lifelines. It can also be clipped to the upper fixation point of your tether.

For high boats, leave some ropes hanging along the hull, reachable from the water.

In Fig.6, you see a 4mm dyneema rope knotted to form loops and with halyard balls (to widen the loops for a snaphook). Place several ropes hanging from the stanchions.

Figure 6. Clipping point. Knotted 4mm dyneema rope with halyard balls. hanging from stanchion.

Materials and Resistance

The laddder is made of independent spliced loops of dyneema rope 2mm with steps of compact polycarbonate. The sleeve is made of coated nylon. The snaphook is 8mm thick, made of polished aluminium (Kong).

The overall rupture load is above 500kg (each step > 500kg, snaphook > 500kg)

Other features

Visibility. Reflective and photo-luminescent marks on the sleeve, reflective material on the steps for day/night visibility.

Maintenance. Sleeve made of coated nylon, easy to rinse and wash.

Reusability: The ladder can be reused many times inasmuch as it is not damaged.

Environment. No disposable part, no waist in in water in case of use.

Configurations and dimensions

VIDEO

Comments and explanations

The boat is about 1.5 miles offshore, adrift. 50cm swell, wind force 1 to 3. The boat is equipped with 4mm dyneema knotted ropes hanging from stanchions (without halyard balls). I am overboard, equipped with tether and harness, I have a prototype of self-rescue ladder in the pocket.

Note. the problems detected during this video (and other user tests) were fixed in the final design.

I first grasp the knotted rope and try to clip the ladder's snaphook. FAILURE! the loops of rope are tightly closed by my own pull. Second attempt: I grasp the tether with one hand and clip the snaphook on the rope with the other hand. OK

I pull out the ladder, and start to climb. Not easy, most of the ladder is underwater, out of sight, I must use the hands to place my feet on the steps. The ladder tends to go below the hull.

Arriving at the deck level, I crawl below the lifelines and struggle for a while to roll inside.

Problems detected (and presumably solved): the ladder tends to tangle, it is difficult to place the feet in the stirrups, the upper step is too far from the deck, the knotted rope without halyard balls is difficult to use.

Design 4 Sea is a registered trademark. Disclaimer, Terms of use, Credits and Copyrights