Day dreamers Idea of a Liveaboard/ Island hopper.

[StreamAir]

My Thoughts, As a non-sailor. Food for discusion.

Every design is a compromise.

Design brief. (Addressing Catamaran/trimaran Pros and cons. )

1 - Dimension Max width 2.8meters (When in trailerable mode).
2 - Hulls with no though holes. (maybe fuel tanks, No storage...nothing)
3 - Wave piercing hulls.
4 - Rotating Hulls - yes I let a little crazy out. Hulls can be Rotated at the waterline for Cleaning, antifoul Painting and repairs if needed. Think Zero Haulout!
5 - Metal Hulls (Steal vs Ali fight)
6 - Distance between Hulls can expand and contract. Telescoping.
7 - Bridgedeck Clearance very high (compromise = higher center of balance.
8 - Aft-mast. design. (Pro easy to single sail, furl, no boom, But comes with many cons.)
9 - Electric Propulsion (Motor fitted and submerged in Rudder below the waterline - Passive cooling - Think IP69 motors in extream submerged Industrial applications)
10 - Diesel power generators
11 - Wheels/auto fenders (see pictures) More Crazy can self haul out/beach crawl....Standard Car wheels.

 

[StreamAir]

PS - Hulls are Water tight segmented compartments....thus the Zero Though holes.

 

[bajansailor]

Welcome to the Forum StreamAir.

Interesting ideas there - but I think I can confidently say that you do not have enough buoyancy in those hulls to support all the weight that will have to be carried above.

And if you want to put a sailing rig on it, the hulls need even more reserve buoyancy to resist being immersed when the vessel wants to start heeling from the force on the sail(s).

 

[StreamAir]

Thank you bajansailor,

Don’t use my silly model as scale….it was only knocked up in a couple hours as a concept. Thinking about the sliding telescoping bent I beams

Hulls can be scaled accordingly.

PS these displace 3ton each…fully submerged…and like you say wouldnt suffice…but will increase exponentially with diameter…or more keel depth volume size.

But the idea being a bit like a hobby 16 where they go though the waves with less rocking.

Ta for the reply,,and good spot comment

 

[StreamAir]

My biggest concern would be how to secure the “legs” to the rotating hulls.

My thoughts are them many ton tow ratcheting straps…but something sharp rubs by and cuts the strap your In trouble

 

[gonzo]

It is a complicated and heavy design. On a boat that small you can simply stand next to it and scrub the bottom with a brush. Wave piercing hulls are usually good for a narrow speed range. Also, they are very sensitive to loading; a very bad characteristic for a live aboard. Further, they are not adequate for sailing. Sailboats require reserve stability. In short, the design in not good. As a non-sailor, the best would be for you to get experience in the water before making a decision on what you want. You may even hate the close quarters, weather dependency, and continuous movement. Otherwise, a simple proven design is what makes sense. If you have a really large budget, a complicated experimental design would be OK, as long as you keep in mind it is a prototype. Prototypes are a testing bed for the next generation design where the original mistakes and problems are fixed. If you think the first try will be a good boat, you are sorely mistaken.

 

[Ike]

As bajan said, those hulls would not support the weight. A simple rule of thumb for pontoons is they need to have enough displacement so only half the pontoon is submerged. In other words the pontoons have to have the volume to support twice the weight of the load. This is because as they submerge the amount of weight they will support diminishes rapidly as the water displaced passes the half way mark. This of course is based on cylinders. If they are more like Canoes or long slim boats with flaring hulls, then the half rule can be modified but still you reach a point where you have no reserve buoyancy. Basically your design is an RV mounted on pontoons. Not a new concept.

 

[montero]

Self haul ideas ?
I have to admit, revolver floats are a cool idea. I think it's a good one, and it could definitely be a good idea for amphibious vehicles.

 

[StreamAir]

It is a complicated and heavy design. On a boat that small you can simply stand next to it and scrub the bottom with a brush. Wave piercing hulls are usually good for a narrow speed range. Also, they are very sensitive to loading; a very bad characteristic for a live aboard. Further, they are not adequate for sailing. Sailboats require reserve stability. In short, the design in not good. As a non-sailor, the best would be for you to get experience in the water before making a decision on what you want. You may even hate the close quarters, weather dependency, and continuous movement. Otherwise, a simple proven design is what makes sense. If you have a really large budget, a complicated experimental design would be OK, as long as you keep in mind it is a prototype. Prototypes are a testing bed for the next generation design where the original mistakes and problems are fixed. If you think the first try will be a good boat, you are sorely mistaken.

Hi Gonzo

Couple of things.....the idea is to think outside of conventional norms....no expectations that this is going to make Lagoon/leopard panic Just thought experiment.
If I had money...Id probably just get a Lagoon 38ft range....and yes I would probable hate close quarters.

The hulls were printed to the 250mm size of my 3d printer...they are not scale...they would be bigger.

Perhaps Wave Piercing hulls is perhaps not the correct term, perhaps X hull...basically a Hull with sufficient buoyance that can take waves over it from all directions....in the roughest seas

The design is limited by width not length. This is the max width allowed on roads without special, abnormal load license / road closer etc.
Think can you live in a RV ....same volume....8-10m length.

The living section sits on top of a metal subframe....to keep the weight down.

Mast aft would attach to the subframe.....for strength.

Thanks for the reply.

 

[StreamAir]

As bajan said, those hulls would not support the weight. A simple rule of thumb for pontoons is they need to have enough displacement so only half the pontoon is submerged. In other words the pontoons have to have the volume to support twice the weight of the load. This is because as they submerge the amount of weight they will support diminishes rapidly as the water displaced passes the half way mark. This of course is based on cylinders. If they are more like Canoes or long slim boats with flaring hulls, then the half rule can be modified but still you reach a point where you have no reserve buoyancy. Basically your design is an RV mounted on pontoons. Not a new concept.

100% - Based on Canoes....for the streamline water resistance.
100% - Airstream caravan on hulls. Be keen to see similar design...if you have links.
Plus - Water strider....
The hulls are not to scale....just the max size of my 3d printer...should have printed 2x bigger.

 

[StreamAir]

Self haul ideas ?
I have to admit, revolver floats are a cool idea. I think it's a good one, and it could definitely be a good idea for amphibious vehicles.

Thanks Montero

Just addressing the more expensive and troubling area's you see people complaining about.

Haulout is expensive and you held ransom to the limited mariners - for Hull mantinance etc.
Lifting in the wrong places and you have expensive damage etc.

I'm not thinking True Amphibous Vehicles....just 1-2Mhp pull out the water and perhaps drive up a flatbed trailer for cross country haul.
Other use:
Perhaps you caught in a bad weather window but have the option of beaching the craft above the high tide mark...for a couple days.

 

[HelmutSheina]

Check neap and spring tides. If you beach your boat on the biggest spring of the year you might have to wait 12 months to refloat it, and if you're really unlucky it may never see the water again. It has happened before.

What are spring and neap tides?

What are spring and neap tides?

oceanservice.noaa.gov

 

[montero]

Thanks Montero

Just addressing the more expensive and troubling area's you see people complaining about.

Haulout is expensive and you held ransom to the limited mariners - for Hull mantinance etc.
Lifting in the wrong places and you have expensive damage etc.

I'm not thinking True Amphibous Vehicles....just 1-2Mhp pull out the water and perhaps drive up a flatbed trailer for cross country haul.
Other use:
Perhaps you caught in a bad weather window but have the option of beaching the craft above the high tide mark...for a couple days.

What do you think about the fact that keeping even passively rotating wheels can be a difficult task in the sense of soaking them in the ocean for a long time?

 

[StreamAir]

What do you think about the fact that keeping even passively rotating wheels can be a difficult task in the sense of soaking them in the ocean for a long time?

I’ve seen galvanised trailer wheels last for years…on boat trailers.
The wheels should live mostly out the water and only during heavy waves, passages…get wet all the way to the hubs. And when used, rotate for hull maintenance etc.

The other side effect is that they are permanent fenders

 

[Rumars]

There are a few practical problems with your concept. First is weight, the folding and hull rotating mechanism is going to add significant weight. This presents you with an interesting challenge: make everything lighter by using expensive materials, shrink the pod and limit comfort or get a CDL to get over the CGWV. As a brit a commercial drivers licence is the only way to get around the weight and not live in a carbon fibre tent.
Then there's height, if you don't want a special permit the boat sitting on the trailer must fit into the common legal limit of 4m. This is doable with low load trailers, but for the roll-on/roll-off you might have imagined with your wheeled cat it would need a custom hydraulically adjustable one, otherwise you need a crane.
Lastly there's powering the whole beach crawling setup and keeping the components from rusting. It's doable, by hydraulic or electric motors, but it would be all custom fabrication and it would not be cheap.

In order to fit into a realistic budget you need to make some adjustments otherwise you can just buy a sh Lagoon 38 and still have money for several haul outs. If trailering is to be a frequent event switch to a folding trimaran. If not, make the cat demountable and transport it in separate pieces. For the beaching apparatus forget the many wheels and rotating hulls, either fit four low pressure wheels on retractable legs (think airplane landing gear) or a set of rubber tracks (from an excavator) under the pod.