Transoms, Ladders and Swim Platforms

pmagowan

pmagowan

Well-Known Member
Joined
7 Sep 2009
Messages
11,836
Location
Northern Ireland
sites.google.com
For the design of a 40' plus sailing boat.

I have been thinking about the problem of getting on and off a larger boat from a dinghy, or even for MOB recovery. Obviously bigger boats tend to have higher freeboard. Lots of modern boats resolve this by having a sugar scoop stern from which you can step aboard. I understand the potential and convenience of such a system but it does not suit me aesthetically. I want to design a boat with a more classic look, similar to a Rustler.

So, my question is; what is the best way of addressing this problem? Do you go for a hinged transom that folds down into a swim platform? Alternatively a small part of it could fold over revealing steps. Or you could have a set of good portable steps that can be attached at the side gate, with rubber struts to hold it off the topsides.

I am quite keen on an overhanging stern (although only moderately overhanging for efficiencies sake) and was wondering if a good system would be a large swim platform folding down to reveal a moderate sized dinghy locker. You would need to fold up a hatch to have steps down onto it (due to the overhang).

What are your thoughts?
Thanks.
 
In a tideway, it's a lot easier to put a dinghy alongside a yacht than across the stern. With the painter secured well forward of the beam, the dinghy will lie alongside very sweetly (a ship would tow a sea-boat here on a boat-rope at fairly substantial speeds) while side-on across the stern it's being swept away. Dinghy bow against yacht stern is more stable, but it's hard to secure it there and more precarious to climb across. So there's definitely something to be said for a sturdy traditional boarding ladder amidships.

On the other hand, when it comes to swimming and other activities close to the water, there's nothing like having a platform mere inches above it. Even something as daft as climbing out when you've forgotten to rig the boarding ladder before diving over the side in a beautiful anchorage (this possibility used to worry me a little with Kindred Spirit's side-mounted ladder, and I probably could have climbed up the bobstay in extremis anyway). Having a stern platform now on Ariam feels like a very convenient "front doorstep onto the water".

I'd be wary of trying to do too much in the way of Thunderbirds folding structure in a one-off fibreglass build, where you need the shape for strength. Easier with aluminium or steel, but still complex.

The possibility has crossed my mind of a small (2'x4') portable platform to go at the bottom of a midships ladder, either suspended from the hull like a painting stage or floating and moored in position. But that's probably wildly impractical.

Best answer? Dunno. It's another of those boat-design compromises :)

Pete
 
Thanks. The transom is likely to be very strong due to the design so I am not that woried about structural issues. I was going to have a second watertight bulkhead a few feet in from the transom to create a large locker for gas and other odds and sods so the actual transom will be like a 'spare'. The answer might be to have both a midships ladder and a swim platform. The midships ladder could be constructed in such a way that it would be a boarding ladder when alongside at a marina and yet also work for bringing a dinghy alongside. One thing I have noticed with my current 'hook-on' midships ladder is that the dinghy rides up and tries to unhook it so there would have to be a fastening mechanism.

I suppose this is another of the things that I need to design and then redesign and then design again. There is going to be a compromise but I want the final solution to be more an 'oh, thats clever' rather than an 'oh, thats annoying'!
 
For emergency use could you use fold down steps. The little Dockrell I bought has them


Rudder.jpg
 
The fat assed yachts that have drop down stern gates/platforms are just the biz. I have sailed on a Bavaria 40 Cruiser with one, so convenient. You could have your dinghy in a lazaret just beside the drop down stern, rather than a garage style. If there was a sea running it may be an issue with a drop down stern and if that is your only access to the dinghy it might be a tad inconvenient.
 
pmagowan said:
Thanks. The transom is likely to be very strong due to the design so I am not that woried about structural issues. I was going to have a second watertight bulkhead a few feet in from the transom to create a large locker for gas and other odds and sods so the actual transom will be like a 'spare'. The answer might be to have both a midships ladder and a swim platform. The midships ladder could be constructed in such a way that it would be a boarding ladder when alongside at a marina and yet also work for bringing a dinghy alongside. One thing I have noticed with my current 'hook-on' midships ladder is that the dinghy rides up and tries to unhook it so there would have to be a fastening mechanism.
Click to expand...

What you describe is pretty similar to what we have. The transom door drops down to form a large swim platform, and a telescopic ladder is hinged above it for easy boarding, a watertight bulkhead forms the forward end of the locker. Our gas bottles are either side of this in separate lockers, and we have a deck shower hose in there to get sand of the dogs feet!. There are two cleats on the aft edge of the door so the dinghy can be tied alongside for boarding. The dink can be deflated on the platform and fits easily into the locker, and in river conditions I have found it easy enough to inflate and launch from there as well, although in any chop I would use the foredeck and possibly the side gates/ladder if the boat were pitching too much. Dink is 2.85 air deck jobby, and we use an electric pump to inflate it, this has its own battery although we do have a 12v 25amp supply socket in the locker as well. The arrangement works very well for us.

BOB makes a good point about when it is rough, we can access the locker through deck hatches as well which are big enough to get the Dink through if a bit of a squeeze given I dont roll it very tightly.
 
Last edited:
The modern trend with fishery patrol / small warships is a ramp at the stern from which a RIB can be launched or recovered from in reasonably heavy seas - certainly more than I'd want to be in an inflatable in.

If the design can accept the space of a short ramp for even a smallish inflatable behind the drop down platform, it seems like a jolly useful thing to me, no reason it shouldn't be extremely seaworthy when physically locked up at sea, and the ramp - with mesh etc - could make a mega cockpit drain.

Edit; the patrol / warship jobs rely on the dinghy being powerful enough to go for it and get at least partly up the ramp on their own impetus before being winched fully aboard, so for the proposed yacht a minor version of this like a decent outboard - with kickup prop -and something to clip the boat to + jackstays for crew pronto would seem an idea.
 
Last edited:
Seajet said:
The modern trend with fishery patrol / small warships is a ramp at the stern from which a RIB can be launched or recovered from in reasonably heavy seas - certainly more than I'd want to be in an inflatable in.

If the design can accept the space of a short ramp for even a smallish inflatable behind the drop down platform, it seems like a jolly useful thing to me, no reason it shouldn't be extremely seaworthy when physically locked up at sea, and the ramp - with mesh etc - could make a mega cockpit drain.

Edit; the patrol / warship jobs rely on the dinghy being powerful enough to go for it and get at least partly up the ramp on their own impetus before being winched fully aboard, so for the proposed yacht a minor version of this like a decent outboard - with kickup prop -and something to clip the boat to + jackstays for crew pronto would seem an idea.
Click to expand...

But you have already told us in another thread that youthink inflatables ate a bad idea so why are you now suggesting ramps for them??
 
Daydream believer,

please put your hurt feelings aside for one moment...

The Fishery Protection / Warships use high powered RIBS.

I was suggesting a vaguely similar ramp to launch and recover a yacht inflatable IN PORT / AT ANCHORAGE might be an idea, when cruising - sorry if I didn't make that clear and it was thought everyone should be SBS !

I have always suggested the place for an inflatable is in a locker on a seagoing yacht to use in harbour for us civvies where lives and wallets are more precious.
 
Last edited:
Seajet said:
... rely on the dinghy being powerful enough to go for it and get at least partly up the ramp on their own impetus ...
Click to expand...

You'd be surprised how little power would be needed. Many years ago we had a Metzeler inflatable with a Seagull on the back(I can't remember which model but I think it was a 40 of some description) and that would easily get most of the dinghy up a beach, so a carefully designed ramp should be a lot easier.
 
PeteCooper said:
You'd be surprised how little power would be needed. Many years ago we had a Metzeler inflatable with a Seagull on the back(I can't remember which model but I think it was a 40 of some description) and that would easily get most of the dinghy up a beach, so a carefully designed ramp should be a lot easier.
Click to expand...

Pete,

yes but when bringing my dinghy ashore under engine I carefully turn off the fuel a fair distance ( 200 yards ? Mariner 2hp 2 stroke ) from the slip, so as not to have fuel spilling from the carburettor in the boot of the car - and of course the GOLDEN RULE is to keep the head of the engine stowed above the prop to promote draining nasty salt water and its' deposits away from the head cooling channels.

I suppose in coastal sailing with such a ramp / dinghy setup for short hops one might leave the dinghy ready to go, + it would be jolly handy in event of an emergency, anything from MOB to ' let's get off quick ' !

The more I think about the ramp idea the more I like it, but - horror of horrors - it might impinge on the space or light from the treble aft cabins of modern yots...:rolleyes:
 
davidjackson said:
................and they save the extra metre LOA on marina berthing fees.

My topsides are too high to safely pick up a mooring so we routinely drop the transom and reverse on to the buoy.
Click to expand...

You must have an extraordinary boat then; ships drop a seaboat to sort out moorings, if the harbour doesn't send a launch, but if no boathook in the world is long enough for you and the peasant crew aren't willing I guess it's time to deploy the flying submarine, or else just run your mighty vessel up the beach and set demolition charges to prevent it running into enemy hands...:rolleyes:
 
Lakesailor said:
For emergency use could you use fold down steps. The little Dockrell I bought has them


Rudder.jpg
Click to expand...

I do like that although one on the rudder I'm not so keen on. I guess that is the only way to get it well below the waterline.

We have a boarding ladder that, when undeployed, fills the gap in the taffrail. When dropped, the bottom rung is around 2 feet below the water. it also has flat rungs (i.e. parallel to the styles) for use as a passerelle. We tried to market the idea but nobody berths stern-to in the UK!
 
Whatever you do make sure you have something permanent that you can lower from the water. I sail single-handed and know that if I can reach the stern I can lower my boarding ladder unaided should I ever go overboard. If the boat is tramping along under auto-pilot then I know there is little chance but having hauled two old guys out of the marina because they had no way to get their boarding ladders lowered after falling in, it is an idée fixe for me. See this thread: http://www.ybw.com/forums/showthread.php?374456-A-Salutory-Tale-for-all-Single-Liveaboards&p=4393711#post4393711
 
Seajet said:
You must have an extraordinary boat then; ships drop a seaboat to sort out moorings, if the harbour doesn't send a launch, but if no boathook in the world is long enough for you and the peasant crew aren't willing I guess it's time to deploy the flying submarine, or else just run your mighty vessel up the beach and set demolition charges to prevent it running into enemy hands...:rolleyes:
Click to expand...

All these boathook afficionados fail to help me understand the purpose of a boathook where the bouy cannot be lifted from the water due to it's short chain length and the topsides of a normal boat are too high to reach the loop that the boat's line needs to be passed though. The only two seamanlike ways are reversing up to the bouy and getting it from a low stern platform/scoop or lassooing then using the dinghy (or swimming) to attach lines.

On the main topic I very much like the idea of a lowering transom with a locker behind it for the dinghy. They look great as well as being functional. I'm not at all a fan of overhanging sterns, though, having had one. If you do have aft sleeping cabins the slap-slap, slap-slap, slap-slap of wavelets under the overhang is maddening.
 
Graham_Wright said:
I do like that although one on the rudder I'm not so keen on. I guess that is the only way to get it well below the waterline.
Click to expand...
These do fold up so shouldn't have too much effect (it's not a boat for racing). I have seen rudders with notches in the trailing edge to use as steps.


Folded up step.

Yamaha4_03.jpg
 
Lakesailor,

I have the same folding step on my boat, it's a little painful on bare feet but a helluva lot better than nothing in an emergency.

For planned swimming in my younger days I slackened off the rudder uphaul line which gives a useful underwater foothold.View attachment 44865
 
You must log in or register to reply here.

Share this page

Top