Trailerable Multihulls

Just some snaps for anyone who is interested.







And nothing to do with anything on the thread but a standing ovation for this effort!

http://www.scrumble.com.au/forward-tape-forebeam-bulkhead/

 

No need for the "with respect", I understand and my request was denied politely and then I was shown the smartness of the system. - When assembled as per the instructions it will automatically break a small wood dowel and lift up clear of the snag/object yet still facilitate steering... and lift fully clear for beaching.... real nifty...

Ahhh Heinz, we posted simultaneously, and the current version is even niftier....

 

Yeah, I had a nylon or similar friction lock of some sort in mind. Completely and easily resettable, paranoid about losing blades, I would tend to sail at sea with one board up where ever possible... containers and all that, would hate to lose two in one go.

 

PS.. with respect was directed at respecting Mr Orams rights/efforts... ie I can understand the request. However as Phil points out the idea is not unique even if Bob's execution might be.

 

No sweat Heinz, I am sure he would retort "It's Bob, if you like." He strikes me as a man who is incredibly willing to help and make sure you are pleased with his support and design because he likes doing it....

 

Hi JCD,

For some reason I missed this thread ! I haven't read all the posts, there is only 2 days in our week here

The catamaran I'm planning designing building is a 30' (10m) sea going trailable catamaran with a full cabin. One thing I agree with Richard Woods on is the full cabin and comfortable living aboard. If I want to be uncomfortable, I'll buy an Alfa ooops, I mean a canoe...

Trailering a large catamaran does have a few challenges. in my opinion none that cannot be overcome. There are some limitations though, the biggest one being the width of the hulls when they are trailed together side by side. My hulls will be about 1m200 each so that side by side they will be within the required width for normal towing. It also allow space for four double berths if you mind not getting off on the side of the bed. One advantage you won't roll out of bed...

Since there is about 1m900 headroom inside the hulls they are fairly high when on a trailer. I use only rub-axles since they trailer low and are the best in my opinion. The hull's would be trailered on a double axle with disk brakes.
The weight would be around 3000kg for the hulls.

The full cabin would be trailered seperately. It will have standing headroom (of course) and would sit on the rear door on the trailer. I have not yet decided how far apart the hull's would be, but I was thinking around 8m, that means the cabin would be about 6 - 7 m wide. I like wide cats, ok

We are never going to the coast in only one vehicle anyway so trailing the two trailers won't be a problem.

We are far from the coast, so getting there is 8 - 10 hours in any case. The idea is to drive there in a day and sleep in the hulls. Assembly would take place the next day and depending on the tide and weather move out to spend the first night on the water, we fish if you remember right

The hulls would be launched and drifted appart using either the beams so they cannot roll over or I have thought of using the front and rear decks to do the same if I can combine the decks and the beams. The cabin is then winched in place and the mast and sail(s) set up. And yes I want it to be launchable from the surf as well.

So far all my seeming crazy ideas that has been tested has worked out very well, ie the launching and drifting apart of the hulls were tested and I was amazed at how easy it actually is.

Anyway, I don't have all the answers yet, but they will come at the right time. I think the day I launch the first time (which will be on one of our fresh-water dams for final testing) it's going to be one hell of a kick in the butt thrill to experience

I like the idea of being able to take your rig to the water, and when there's no more fish to catch, take the boat back home. This is the only reason I'm building the cat. I would not have considered it if the cat had to sit in some harbour which in my opinion is expensive to do and your mast gets stolen in the first week there kind of thing. My only handicap is we are far from the sea, I know most of you live close by, you're so lucky

The cat, at the weights I calculated is the same as some of the larger ski-boats here, just the size and width is a little different as will the comfort aboard be. Excuse me, I have some things to make for the cat...

 

Hello Mbz, Masalai and Fanie,

Thanks for the pictures. Very nice set-up and it looks easy to operate. I'm not sure that those will be right for the TR27B since it appears that you need an open and low inboard. But, you never know. The boats however are beautiful to look at.

I'm not sure how much time I have. The grandkids came from down south for a surprise visit and I've been spending lots of time (all my time) with them. It's amazing how much energy a 4 and 5 year old can store and use with little loss. It is freaking nuclear. Right now they're recharging their batteries and cooling their jets (napping) because I burned off some of their fuel by making them run around the park twice and wash and clean the 32 footer from bow to stern.

Ahhh...I do love them. Then they grow the hell up.

Fanie, welcome to the thread. Glad to have you on board.
How could you have missed the best thread on the globe?
Didn't you suspect history may be in the making?
Take your time and go through the thread 2 days a week and ask questions or provide insight or recommendations when ready. We will still be here. I will get to your post as soon as the little ones give me a chance or live, if I live to do it.

Whoops, the missile and torpedo are actively seeking me out by radar (wife)and they are locked and loaded onto my signal so I gotta go. No more horsey rides today and I'm sticking to it.

J

 

J for what its worth, if I do end up building a Sango, I will build in "step on" transom's for easy access from the water (dinghy & swim) and from the land (trailer & stern to beach). That would mean that rudder setups need to be reviewed and one option would be the cassette style, given my boat will spend most of its time in the water it might make sense. The main priority being easy walk on access, something that small boat designers, for some reason, seem to discount.

 

That aspect has been worrying me too Heinz, I thought of a lowering thingie from the bows to act as a plank when playing with the anchor/bridle etc the advantage is "drive up to the beach" and your stern/propellors and rudders are "safe?" - not very happy with that - and then there is the spoon/scoop at the stern - yea, but as time and other factors make it more difficult to get up to that water-level and sit also clear of props & rudders again a worry???
Lowering a section like a fork lift picking up from 3 ft below the water level - has been done with a simple winch which can be locked in any position, seems good for tender and elevator to get people and stores to reasonable "lift in" height too - needs lots of work and weight reduction but could be good....

 

On a big boat I would have both the walk on transom and the bow ladder. The bow ladder I would attempt to set up so that it acts as steps when on a beach but more a ladder projecting below the water when afloat. Stern steps can also carry a flip down L shaped one or two step ladder to help out when U R submerged.

Cassettes when backed onto a beach... yes that's a problem. On a big boat solid skegs and fixed rudders maybe the best option... a weight bearing setup.

A strong dinghy platform/dive platform/goods lift, yes could work... aluminum lattice? big boat stuff, not helping J much.

 

I have seen it on that 37 ft thing from China "multihull haven" bob something?

 

In my rudder system the rudders lift nearly vertical, rather than angle back (as shown in the top photo of a Dazcat). Incidentally that photo was taken in front of my office at the Multihull Centre, Millbrook - although you cannot quite see it in the picture as it is just out of shot to the right.

There are two reasons for lifting rudders vertically. First it helps prevent damage from boats cutting close astern one dark night (more than one lifted rudder has been ripped off that way). The other is that in any seaway the lifted rudders rattle and bang and a more vertical lift reduces noise and loads on the hinges.

I don't like the cutaway hull side. That is because as you sail in waves the hull pitches up and down. Clearly if the hull is cut away there is a loss of buoyancy as the wave washes up and over the step so the boat will pitch more.

The Wizard has a transom step, but I didn't draw it on the Sango as it is more work and a small metal rung is easier to fit. Because it is a small boat free board is relatively low so boarding over the side from a dinghy is easy. If you want to get on board after swimming then a boarding ladder is probably the easiest and lightest solution.

Just my reasons for my rudder lifting solution. As others have said lifting rudders is a common idea, especially in places like Millbrook where boats dry out for 12 hours a day.

Hope this helps

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Thanks Richard,

I can also add that vertically lifting rudders are good for steerage in shallow water, my tilt rudders are great if you hit a bank (shallow around here in some spots) but once you have the rudder tilted up steerage is next to impossible, where as a lifting rudder is still some what effective at half height. Some combination of lift and tilt is required i.e a dagger board with a tilting "crash box" or some such thing.

I personally would look at extending the boat a little if that was what was required to gain walk up transoms and a platform of some sort at or very near water level. Basically add area that is not required to make the buoyancy equation work. Its just absolutely essential for the way I use a boat and a major short coming of the SW24 (IMO) which despite being lower than a Sango is still a pain in many situations. Think kiddies and wives , them being a major part of the reason for choosing a multi I have to go the whole way to make the boat work for all their non sailing activities

The other thing I would do is an open back cabin as per the Farr 6000's 3 storm board arrangement. This makes the cabin apart of the sailing/social area on the boat when required. These two simple things make a small boat much more usable in summer IMO.

I guess its all just personal preference at the end of the day.

Cheers
MBz

 

Farr 6000 happy snaps

 

Meanz, had any more thoughts on the mod pod? I did some scetching on the white board the other day, -gotta sceme up my new hard deck for my seawind including outboard mounting so I'm thinking forward to maybe fit a mod pod too if I keep the boat. Regards from Jeff.