Need help with laminate schedule and drawings for 52 ft catamaran home build

Need help with laminate schedule and drawings for 52 ft catamaran home build project. It's a coastal cruiser catamaran that is being built using 3/4 divinycell and pro set epoxy, hand layup by qualified labor team. Looking to hire someone to consult on the project.
Email
Ismotorsport@yahoo.com
California USA

 

How is it possible you have a design without a laminate schedule and some, if not all of the drawings? How is it you preformed a weight sturdy, to insure it'll float where you pain the boot stripe, as the laminate schedule would play a substantial role in this regard?

Can you explained what you actually have and who drew it up? If the author wasn't qualified to preform schedules, then you have little more then a concept and a designer or NA, needs to be contracted to preform a full up custom or possible alterations to one of their stock designs.

 

Par,
Not to get into incredible detail. I contracted an na to produce a hull design and appropriate interior structure and bulkheads to suit my home build project. It was designed with a certain layup and materials in mind. The numbers you speak of were based on that and have all been calculated. The na was more than qualified to do the design and has done similar designs that exist today. However my budget and his
schedule do not allow for his continued involvement. I am looking to outsource this part of project that is why I am posting here. I have received several responses thus far. I understand it is better to have a single na involved start to finish but i dont believe my approach is not unorthodox as many big na firms end up sourcing this part of project out anyways or have their in house engineers work on it anyways.

 

Just to add some information for any interested parties.

52 ft coastal cruiser catamaran
displacement 20000 lbs
Minimalist interior structure ( gelcoat finish, no headliners)
Basic boat systems ( two heads, plastimo flex water tanks 50 gallons each, double propane burner stove-no oven, dc icebox refrigerator, 12 gallon water heater, single Genset with twin electric sail drives, 400-800 ah battery bank, fresh water pump x 2, holding tank x 2 gravity empty, led lighting, lewmar hatches, harken winches, basic nav system, berth cushions, etc.)

Build is via male plug, hand layup divinycell h80 and h100 where needed.

Thanks.

 

If you involve another NA or designer they will want to re-run all the calculations so they are starting with a level playing field. Conversely, they'll probably call the original NA and see how much cooperation they can get in regard to the design basics.

Considering the cost of 52' multihull build and the stated budget restraints, on the most important aspect of the project (the design), imposed by the client, it would be unlikely another NA, will consider taking on the project. I mean no offense with this, but it's a common issue. "Can you finish up my drawings for me and I can only pay $500?" Knowing they have to go around the whole design spiral, in spite of existing drawings and specifications, still means it's a full up custom and most will expect a reasonable fee for this. In short, there's no savings with preexisting drawings if the design is incomplete. This is simply because nothing can be assumed when you're farther from shore then you can swim back to, so all the calculations need to be preformed or in these cases re-preformed.

 

PAR,
While I understand your point. Having the files for the design with all the calcs you speak of readily available I do not believe that a na has to redesign from scratch, just reconfirm the numbers with program of choice. As for my budget, I never stated $500 and have spent well more than that thus far. My budget just doesnt allow for 100/hr design work. The spiral has been gone through several times and not having seen any part of the design, I find your comments baseless.
If you are interested in the project and need the work then by all means email me and i will happily discuss the project. Or on the other hand if you can provide me better guidance or advice that would be greatly appreciated. thank you.

 

hi there we would be very intrested in helping you regards joe sigley
go to www.j-s-composites.co.uk

 

What have other cats of a similar size and construction used?

 

Not following your comment sabahcat? I do have an idea what has been used on similar size cats. I just don't plan on reverse engineering a project of this scale. I am happy to pay someone for their services hence my reasoning for putting this is the employment section of forum. I am sure that if I just posted a question about the laminate schedule for a catamaran of this size. I would have gotten some wise baseless remarks about how impossible it is to figure out. I also understand that if I speak with 10 na s I am liable to end up with at least 12 or more options. I hope that a qualified na could complete the laminate work based on all the work that has been completed thus far. if you are interested in the work and available please let me know. I have had a few inquiries to date and waiting for feedback.
Contact info is Ismotorsport@yahoo.com

 

Hi there just to say I have a cat rib mould for sale if intrested contact me joe on info@j-s-composites.co.uk or go to j-s-composites.com

 

If it was all already calculated and there is a laminate schedule, do you need a second opinion? Do you not trust the previous NA? If you don't, neither will another NA and it will take a fair amount of time to recalculate everything.

 

Gonzo,
You are correct in that it has been calculated. I would like to hear what others in the industry are doing laminate wise. As they say, there is more than one way to skin a cat....no pun intended.

 

Dozen people have already told you what you dont want to hear... All of the engineering has to be redone in order for someone to give you another laminate schedule. All of loads need to be recalculated - your drawings that you have, i bet they do not state the compression load of the mast or the rigging load on the chainplates for example do they? Therefore, noone can just pick up your existing drawings and give you any quick advise or recommendations - the prudent engineer will always recalculate from scratch as it is the only sure way to engineer something theyre willing to put their name to - not only for their reputation, but in case the worst happens and someone gets killed and everyone ends up in court...

Without knowing anything about your boat, all i can say is that many catamarans in this size range have been built with around 1100gsm triax e-glass/epoxy hull skins on 3/4 h80 foam cores... this is the easy part tho, the beams and bridgedeck laminates vary alot depending on the rig size and type, and floor plans and how much stiffening can be acheived by using furniture, saloon cabins or the general arrangement and shape of the entire boat really... panels with curvature are stiffer than flat panels etc...

Your not going to find easy/cheap answers that will compare to a well engineered solution... you could just over build everything and pay the weight penalty - which will likely cost more in materials than the engineering work itself... or underbuild and try to sleep at night... upto to you...

 

Thanks Groper,

I appreciate the insight into what other cats in this size range are doing for laminates.

Without seeing any part of my design or numbers associated with it, I understand it's easy to say it should all be reengineered... No offense taken there...

The sole purpose of my post is to see what other boats in this size and range are doing as before I throw more money at the project. Trying to get a relative comparison to see if the current na I am using is over building the boat relative to others as you suggested is easy to do. Having read some other threads I noticed quite a differentiation of opinion on proper laminate plan for performance catamarans. Some opt for light vs others go extra heavy??? Would like to hear pro/ cons of each for a custom build like my own.

Please keep the insight coming... Thanks.

 

There's no such thing as a preformance cat with an extra heavy laminate schedule. Assumptions are for circumnavigators in 7' boats, but the rest of us don't attempt to draw these types of comparisons, as there are so many possible variables, that "averages" just can't be accepted as a "norm" for a particular length or configuration of vessel.