You’d think 132 ft. (40.2 m.) is enough but, it’s never enough 
.
We’d like to create a little bit extra space for our dive tender. We were looking at 7.5 m. Humber Inflatables (2.8 m. wide offshore model) and 2 extra feet of boat deck would be nice. We’ve now decided to go for a custom aluminium tender design (see post (…soon). It would also give two extra feet of tip clearance if we have to land with a helicopter. That’s about a 25% more than we have now although since we wrote this post, we decided (September 2009) to create an extractable helipad.
Click on the image to see it bigger and let us know 
what you think.
It’s been some time since I wrote about this topic but we finally figured it out, partly due to experiences during our last crossing and conversations with people in the field.
The initial plan was to use (heavy) aluminum tenders which required a heavy crane and we didn’t really find a satisfactory solution on where to place it. Now that we decided to use RIB’s as tenders we can use a lighter crane which means lower price and a crane foundation that can be a little lighter too. That in turn means new options on where to place the crane.
We decided to widen the top wheelhouse deck at the location of the life rafts. The widening means not only more space to fit in a crane. It also gives us a drier deck below and makes launching the life rafts easier.
The crane we plan to buy is an MCA-approved model from Canadian manufacturer Steelhead Marine. Their cranes are well designed, look good, they have a great website and their response time and quality of feedback exceeded our expectations.
We like diving and as a true expedition vessel, we’ll be set up for serious diving. We’ll also plan to go with aluminium tenders. They simply last longer, give us more design choices and are more affordable then fancy looking RIBS.
This is our aluminium dive tender, a Van Vossen Engineering design. Rugged, built-to-last and with some very unique extras to make boarding a piece of cake.
We plan a 235 HP Yanmar engine with a stern drive.
.
Since we eventually would like to be able to carry a 7 ton submarine, we need a pretty strong crane.
We’ve been looking at hydraulic cranes but they are not cheap and the location, while acceptable, did leave us with kind of a big ugly object in the line of sight forward.
Since we have a pretty strong forward mast anyway, our designers at Herman Jansen made this suggestion – a boom – and we like it a lot. It’s a lot more affordable while able to carry higher loads. It also looks a lot better we think.
Now we’re going to find a way to do the same for the tenders on the platform aft.
We can’t use the same set up behind the mast because it would reduce the safe area to land a helicopter. Maybe a small hydraulic low profile (stiff) boom crane after all? We’ll figure something out.
We plan to carry two tenders and would carry them on the aft deck during longer voyages.
Now that I received an AutoCAD drawing of this deck, I started to play around with the location of the tenders and it looks like the setu shown here works best.
The aft ends of the tenders will extend a little beyond the deck to allow walking space around the funnel superstructure and allow people to come up the stairs without hitting their heads against the bow of a tender!
Alternatively, we can also keep a tender at the top deck near the bow. Or simply keep or tow them in the water. We’ll probably put a small tender crane at the port side of the funnel superstructure. The one that would also puts the float plane onboard, remember ?
.
If this isn’t the ultimate explorer vessel, then what is?
We plan to have two aluminium custom-made tenders. After looking around we found they end up costing about the same or less as RIBs like Novurania yet last forever.
We’ll equip them with diesel engines and traditional shaft driven props. Gasoline fumes tend to ignite very easily so we prefer not to keep it on board for safety reasons. Besides, diesel engines require less maintenance and are more reliable.
The design is in the hands of Van Vossen engineering in The Netherlands and based on their Twister 680 model.
what you think.
