Boarding platform

A transom boarding and swim platform for Camomile

Boarding platform and swim ladder

When we were in the later stages of planning our blue water trip it became clear to me that, once we were outside Europe, we would be spending most of our time, when not at sea on passage, at anchor or sometimes on moorings but rarely alongside a wharf and hardly ever in a marina. Camomile has a plain transom which makes it easy to fit davits, steering gear and so on but only had a small boarding ladder and lacks the arguable benefit of a “sugarscoop” for access onto the boat. This meant that we needed a good system for getting on and off the boat from our dinghy and also to have access to swim as well as providing, if possible, improved handling of the davits, wind steering rudder etc. I decided that an aft boarding and bathing platform would be the best answer for most of our needs with a back-up of mid-ship access when it was too choppy to get onto a dangerously pitching transom. I identified what I wanted the system to do and it’s important properties:

1. Needs to be low to make for very easy access from the dinghy and the water. In the early days this was really important to Sue as she used to be nervous about her stability in the dinghy. This is no longer an issue however we still often have guests who get off our boat with a lot less personal stability than when they arrived!

2. It should be able to flip up so that in choppy conditions the dinghy can be held alongside it without risk of its tubes being trapped underneath the platform. I have seen a number of dinghies completely ruined in this way and the opportunities for hurting yourself in the process would be obvious to anyone who has ever got any part of themselves trapped between moving boats.

3. It must have a ladder to board a swimmer/MOB from the water

4. The Hydrovane wind steering rudder must be made accessible without dropping the dinghy or getting into the water so that it can be removed after passages to prevent weed growth and to “rest” it from constant use, flopping back and forth at anchor and jiggling in the propwash while motoring.

Retracted

5. It should be big enough to accommodate 2 people or 1 person and gear being loaded.

6. It should have an easy grab rail to hold onto when alongside in the dinghy or when getting out of the water. When I had started to get a reasonable idea of what I wanted to build, I got some simple drawings together to gather a rough idea of the cost. Even though I have had many stainless parts made before I still got a shock when the costs came in. This meant a re-think but I really wanted to find a way to drive the costs down rather than remove features from the design. Eventually I came across Baseline Marine, a UK company, who stocked a superb range of all the stainless components I needed but provided them as off the shelf series parts rather than as bespoke items. I felt, since we were going to spend years, full time living aboard on anchor that this project was worth spending some time getting right as I was sure I would get good mileage out of it. Designing in the ability to flip up or retract, while adding a complexity, also had the benefit of being able to keep the platform low and wide because, in the retracted position, it would not become immersed underway as the wake and heel moved the waterline up the transom.

Lanyard

Also, when lifted, it is difficult to access the aft boarding area from the water which discourages random swimmers or unwelcome guests from getting onboard without an invite (it happens). The lanyard which hoists and holds the platform up has however been fitted with a “ripcord” (made from a series of cable ties and a plastic knob on the end the line) to make it accessible from the water such that, when it is dangling, it can be tugged to release the platform into its down position. The noise of the platform falling freely would alert anyone on board that it had been deployed and all that is needed then to prevent this access from being abused is to lift the knob up and away from arms reach at the waterline. Recent experience with using a stern anchor to hold us bow into a swell or restrict our swing (as required by some harbour authorities) has also revealed that the retracted position also helps avoid the rode chafing or becoming entangled with the platform. The platform is supported by four telescopic shafts which are simply one stainless tube sliding within another and fitted with a standard end from

Ripcord

the Baseline catalogue. The lower part is coupled to a rigging screw end which is bolted through the transom and glassed over inside. The pivot point is made with through bolted teak blocks onto the transom, sized to align the pivot axis along its curved surface and fitted with the same end bracket which comes with the Baseline standard transom platform framework As it turned out the only tricky parts to making the platform rotate were about preventing a pinch point between the inner slats and providing access for the Hydrovane steering gear to pass through the slats. The pinch point was eliminated by articulating one of the slats to allow it to slide during rotation driven by a small strap. I was convinced that this would fail or jam however after 3 years of use, so far , it has worked very well. Access for the removal of the wind steering rudder was achieved by making a small trap door in the platform slats and again, although this looked weak to me, I have been pleasantly surprised to find that it works well if not abused, although I suspect on a commercial boat that both these devices would need

Strut fitting using through bolted rigging screw end

engineering more robustly to survive. I had also noticed that many boats have stern “swimming” ladders which only extend one step or so below the water and ours was one. This, in my view, is a waste of time as, at best, it is unergonomic and at worst painful/injurious to use so I made sure that ours extends 90cm below the water by using a telescopic version from Baseline and have found this to be a sensible minimum for a swimmer. It also makes very good sense when we are dried out or on the hard as, if there is no ladder to hand, I can still get aboard with a just

Wind steering rudder access

asmall step. The ladder is positioned centrally with grab rails both sides and the wind steering shaft in front so that there is plenty to hold on to when getting out of the water and the ladder also provides useful buffer to prevent the dinghy getting under the platform. If the dinghy should get under the corners of the platform then it simply lifts and the telescopic supporting arms push it away without damage. I did not have to provide any step or grab points on the upper transom as I found that, with it’s lower (and redundant) part removed, the

Articulating slat and Baseline Marine fittings

original Westerly ladder served this purpose readily and also provided a cleat to secure the hoisting lanyard. Since fitting the platform in the UK the only change I have made in that area is to add a freshwater hose with a shower head to rinse the salt off after a swim or clean up dirty feet/shoes after a shore expedition. This incidentally is cold water only on the basis that it kept the plumbing simple and with seawater at 25C and 30C air temp in the shade, a hot shower is rarely called for! Finally it is worth mentioning that, while we use the transom 99.9% of the time and it is one of our favorite spots for a sundowner while cooling our feet at the end of a hot day, we also have a fender step for mid-ships boarding when it gets too rough for anything else and that our MOB recovery is an entirely separate and independent system designed for short handed, blue water conditions.

Midships boarding

Original ladder and added shower point

Spec:

- Description: Lifting style transom boarding platform consisting of teak slats 55mm x 15 mm over a 22mm diameter tubular frame supported on 4 telescopic tubular struts and rotating on 4 pivot brackets all through bolted and glassed inside to GRP transom

• Material – Teak and 316 stainless steel

• Platform dimensions 1100 mm x 500 mm

• Platform height above water 240mm

• Length of swim ladder approx 400mm retracted.

• Length of swim ladder deployed 1100mm with 900mm submerged.

 
  1. this is exactly what i needed to complete my drawings.

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