Possibly dumb question (my personal specialty) - but are those big bottom hinge doors locked down in position or allowed to float? Kelly
Hi, The two stern launching systems I have been involved with both hold the doors down with hydraulics when launching and or retrieving. The hydraulics have to be man enough to submerge the door in the first place as well. After the Tender is launched the Doors are returned to the horizontal position or it can be closed if the main boat is going to move and the Tender is going to be elsewhere or whatever the operational requirements require.
Humm, fun to contemplate. At this point I'm wondering if the type with the platform separate from the door, as seen in the photo in Bruno's post, is more practical than a bottom hinged door ..... Kelly
I often wonder how does Octopus get her main tender out " Man o WAR" out of the marina garage. When the stern door is opened the boat can only come so far. When she wants to leave the mother ship what happnes? I know that there is a set of steps in the middle of the bathing platform. I wonder if this area is forced down into the water by hydraulics like seen in Bruno's post or if they are retracted somewhere to allow the tender to pass in and out of the mother ship?
I too have been very curious as to how the main tender garage works on Octopus. I assume it works like a dry dock that can be filled to sea level when exit/entering is required and pumped dry with vessels secured during voyage. What about the center transom platform, does it lower into the water? Cheers all
K1W1, about the trailers used on the stern platform, do you know which was the supplier? Were the trailers rolling on the stern door or cantilevered above it? Are the pictures in attachment a correct representation? With regards to the Neptunus-photo in my previous post: - I don't know the size of the tender. - It looks ideal, because you have the luxury of the platform lift also when the tender door is closed. That is great for older people or divers. Climbing up a standard swimladder can be hard, especially if there's some rolling going on. With the swimplatform lowered, you can just swim over it and stand up. But: If the lift mechanism ever breaks down, you're left without a tender. I wonder if the MCA would accept that if the tender also has to be the rescue boat. Maybe they accept it if you can lower the platform with a manual pump? Anyone any experience? Bruno
Hi, Bruno; On the boat in your picture the trailer was powered by hydraulic motors in the front that drove two sprockets and a large pitch stainless steel chain was laid in the bottom of the tracks. The trailer travelled all the way out in tracks to the aft end of the platform where it was retained by two small stainless steel clips welded onto the door frame. The front under section of the trailer pivoted so when the trailer was on the door and it went down the drive section stayed down on the deck in the drive position. The rams of the door did all the up and down action of the boat, trailer and door. The sytem in use at present on there has had major modifications and now works a lot better. The one I am dealing with now doesn't touch the door at all, the door goes down and then the trailers go down but stay clear of the door at all times.
Transome doors? I have a question after reading the posts, and thinking up my own stuff, why not spliting the transome door and slide it open like a van door. this might make the doors push out past the beam and would not give you a swim or dive platform, unless you made other arangements, but I thought to ask anywhy. As for side of the hull openings, I would favor the doors opening down. It gives you more options to use the space.
That is a really good idea....however, i am thinking that there maybe problems with stability of the yacht as if the yacht is anchored in a BAy...the wind might blow on the doors extended over the beam at the stern and casuse the yacht to shift around. That might be the only problem with that design.
I have worked on two large yachts with aft garage doors. Both vessels had so many flaws with each system, water leaks, exhust leaks, hydraulic issues, so and so on. Mind you the garages were nice and functional for the guest and all but they were just so problematic. Has other people had the same experiences?
I've wondered a bit about ventilation and trapping nasty gases in stern garages? Station wagon effect on steroids? Kelly
This looks like a nice system www.tbv-industry-offshore.com/onderhoud/upload/megayacht_com_tender_launch_19-8-05.pdf
stability I love having a garage to work on tenders, jetskis, dive gear etc but: side doors with a garage floor below waterlevel and a minimal freeboard gives rise to a potential huge decrease in GM due to free surface in the event that a sizable wake / wave washes aboard. Or if the side doors develop leaks on passage. This of course can be dealt with by having gratings in the floor to rapidly drain the water to bilge spaces with several longitudinal sub divisions and high speed pumps, but are these precautions taken as standard? why have a large proportion of the 500 GRT that a typical 45 -50m yacht tends to be limited to used for toy accommodation!? Surely better for the Owner to have the whole 500 GRT volume for them (and the crew) and have the toys outside to be launched on arrival at anchor if they are on the entertainment decks or locate them out of the way aft of the wheelhouse or forward.
Princess Marina is a very Good example of having a good transom door. Down there is a nice relaxation space and the storage for the main limo tender.... so the transom door is usually seen open regularly as it allows light to come in and illumiate the space!
Skat's own is pretty interesting, top hinged doors that literally seem to dismantle themselves from the actual hull of the yacht