Hull Construction

Hi all,

I've had to return to England because of my sons' education and I'm gonna have to be here for the next 4 years, so I've decided I might as well use the time and build that boat.

I have been involved over the years with various projects mostly completely strip out and redesign/refit of existing hulls that we may or may not have had to repair, but never designed or built a hull. I have an animation company so use loads of different modelling and animation software, to come up with an accurate design and pretty picture interpretion is no promlem. I am looking for an application that will access the design characteristics of what I want, which is.

I plan to live in this boat, so size is important I was thinking of 20-25 meters with a generous beam. She will mainly be out in the Pacific, messing around with me diving and what not, so draft is important and that got me on to thinking about twin keels, shallower draft and more importantly the ability to get them out of the water for maintenance etc. She would also need to be easily short handed and crammed full of high tech stuff (I like that sort of thing and really need it!!)

I was thinking about a composite construction with a steel hull and a light weight steel super structure used as a form for the GRP or even carbon fibre over that. Which would create a realivity light weight vessel for this size but with great strength. Then I got to thinking why not do the same to the hull, use a thinner gauge steel with either carbon fibre or GRP over that (OK it might take a year to sand down but that I got) Thereby considerably reducing weight, give a nice rigid hull and allow more weight into the keel bulb.

What does anybody think? Have I totally lost it having spent to many years in the sun without a hat on and stick to oing the lottery in the hope of a Swan.

Nic

 

if you want a solid and light boat why don't you make it in aluminium? i think it should cost less than stell covered with carbon fiber , also less maneintance ,no painting....

 

Hi,

Yeh thought about ali but rejected it cause I've seen what a coral out crop can do to ali and I'm more comfortable working with steel as well as having all the equipment for steel.

The end finish I want to be a gel coat type, so I guess to achieve that you would need to have an epoxy/fibre layer over the ali skin.

 

Nic,
If using steel, then do not cover with carbon as it will be a biyatch to repair. Simply use steel and repair if needed with a welding torch on any beach in the world.
Steve "simplify"

 

Nic,

Sorry to put in a commercial plug (don't know if it is allowed, maybe someone can tell me - don't do it often - just trying to be helpful Mr. Moderator - Nic did ask!!!).

Contact me if I can help you with the build Nic (see our website www.boltonprofiles.com and my e-mail is paul@boltonprofiles.co.uk).

I will personally look after you if you contact me and I will stay with you before, during and after the build as I handle all the boat and boat related enquiries myself. No one else will be involved, so you can contact me personally 24/7. We have many, many delighted clients who still keep in touch which is really nice and I can maybe help you to find the design you want. We profile for many designers world wide and of course in the UK and Ireland, so I am sure we can come up with something and which we have probably completed something similar before.

We have profiled narrow boats, w. b. barges, yachts, trawlers, landing craft, powerboats and pretty much everything in between.

Give me a more detailed overview on what you are thinking about with some detail on draught, type, internal requirement, price and so on.
I have a new design which could fit your requirement which I am really excited about - special discount for the first one as we may need to tweak things by a few mm in practice and this may be an ideal oppertunity to try out the prototype (we need one for the London Boat Show so can hire it off of you then if you are agreeable and at those rates will go a long way to recovering the build costs). This design is from a top designer who you will know (not Bruce Roberts) but I can't say too much about it at the moment.

Also, I have now built 4 boats myself, so although I am no expert, I do have a good understanding of what is required. I can perhaps also help with the build but with all of our designs, you would also have complete access to the actual designer and his team if required.

We pride ourself on quality and a no - quibble policy on any problem parts - should they occur.

If you already cut the parts yourself then fine, no harm done. I will still help on the design though if I can and if you want me to.

Paul.

 

Hi,

Steve I know you are correct unfortunately I am a designer not an engineer and I've goit that pretty picture in my head of a high lustre midnight blue gel coat, what can i say?

Thanks for the info Paul will be in touch.

Nic

 

Nic
You may have trouble getting the required overall strength without the steel deck in a 22m hull unless you go heavy on the hull.
Its that design spiral that curves around and pokes you in the back.

Even if you used the expensive composites you are still going to have to bolt them to the hull so you need the deck beams doing more work than they would if a steel deck was welded to them.

And that midnight blue is going to get awfull hot in the Pacific tradewind belt, looks awful covered in non skid deck paint too !

 

Why not go steel hull with aluminium superstructure?
You get the weight where you want it.
Aluminium is easier to work into 'attractive' shapes for the superstructure, then you can fair it and paint as desired. (I'd stick with the blue for the hull, if you have to, and go with something a little lighter for the superstructure. As Mike says, the heat can make life uncomfortable and dark colours don't stand up over time as well as lighter ones.

 

Nic,
If you cover your steel with carbon fibre you wouldn't need batteries any more. Carbon causes galvanic corrosion in most metals. Not a good idea.

I hope you don't want to design and build a 25m yacht on your own. I don't think that 4 yours would be enough even if you worked 24h a day and remember your son is supposed to study and not help you with the welding.

I would at least get a professional to design and engineer the boat. It's not a piece of cake especially if you want to cross oceans and sell it for more than scrap metal prices. This will be money well spent.

I don't know if you want a sailing or power yacht. You could build both from composites (glass, carbon, foam, epoxy). This will be by far the lightest structure. A metal hull with "plastic" superstructure would be an option too. And remember you have to handle all those heavy steel plates somehow. A bucket of resin is much easyer to move.

Cheers,
Karsten

 

Nic,
As a designer AND engineer, I can assure you that it is a waste of money to use gelcoat over carbon fibre. THe only reason (apart from free power) to use carbon here would be for the look, but gelcoat will hide the carbon look.
Put your money into fairing compound and paint.
Steve

 

...and I'd back Karsten suggestion. Get a qualified designer to design the boat. It will be money VERY well spent.

 

And from a practical seamans point of view (you have to maintain and use this thing - right? you don't want to spend all your life doing that? use IS more important - right?) stick with what the designer chappies are saying above (yes fellahs I'm agreeing with you! first time for anything) Plain steel and a good paint job is superb - look at the old Royal Yacht beautiful (polish and a gold stripe but still steel and paint! - blue too!) Keep the topsides and decks etc a nice light colour for coolness in the tropics etc!