My custom design 62FT DS homeboat

[Rumars]

Strip planking composite with vinyl ester GF is what I estimate to be a good balance between labour and investment in machinery.

Resin infusion, although requiring meticulous planning for execution, is a highly effective method for glassing the wood core.

Please no ester resins with any wood other then balsa. Epoxy only.

One of the big decisions for this boat is the ballast. A minimal estimate is 10t, and possibly even more. If it's inside ballast the only choice for this canoe hull is lead, 10t cost 20 000€. This has to be added to the initial cost, launching unballasted is far from ideal.
The budget option is heavyweight concrete, but that has to be installed outside as a bolt on fin/log, increasing draft. It might also call the daggerboards into question.

Now, 20 000€ more then covers the materials for the additional surface area of a catamaran. The only thing remaining is the perceived "safety" of a monohull. If this is to be a inside ballasted boat the righting curve will go negative at around 100° (best case). After that it's roll-over time and sinking is a function of having all the hatches closed and the saloon windows holding.

The cat on the other side might flip (extremely unlikely for a cruiser) but will not sink.

 

[Vinicius Miguel]

10t is a fair assessment,
I am considering using steel boxes filled with coins from the stamping process, which can be purchased relatively cheaply from scrapyards. The gaps can be filled with molten lead to improve density.

 

[Rumars]

10t is a fair assessment,
I am considering using steel boxes filled with coins from the stamping process, which can be purchased relatively cheaply from scrapyards. The gaps can be filled with molten lead to improve density.

Sorry, I don't think that will work. The volumetric density will be to low to achieve a decent righting angle and you will also run into problems of longitudinal ballast placement. If you want anything other then cast lead you have to place the ballast under the hull.
Inspiration, but this is a much lighter boat then what you drew: Integral 60 - voilier d'expé https://www.sailworks.net/index_gdint.htm

The boat you copied the hull from used 10t of lead ballast in a L shaped bulb fin, placing it 2.5m under the waterline.

 

[Vinicius Miguel]

Sorry, I don't think that will work. The volumetric density will be to low to achieve a decent righting angle and you will also run into problems of longitudinal ballast placement. If you want anything other then cast lead you have to place the ballast under the hull.
Inspiration, but this is a much lighter boat then what you drew: Integral 60 - voilier d'expé https://www.sailworks.net/index_gdint.htm

The boat you copied the hull from used 10t of lead ballast in a L shaped bulb fin, placing it 2.5m under the waterline.

Rumars, I dont see how that would be the case a solid steel box (not considering the gain in density filling gaps with lead), a 150mm x 300mm x 18m is already 10.5 tons, this can be made as the keel line stringer.

The beam can be made in 1m segments and then welded together in place.
The segments can be made of laser cut boxes following the hull geometry, epoxy bonded and bolted.
It is a very practical and affordable solution compared with casting a large lead beam and a fraction of the cost.
Cheers,
Vinicius

 

[wet feet]

I'm somewhat puzzled by this whole project.It seems to be very thoroughly planned in most respects but we haven't seen indications of boatbuilding experience and we have a very large boat planned for the use of a solitary occupant,yet it has a lot of accommodation.If the plan is to use it for commercial purposes,won't it be necessary to demonstrate compliance with the applicable regulations?Which will almost certainly require a competent designer to verify several aspects of the design and a surveyor to monitor construction and equipment.There is also the very real possibility that it will take such a long time to build that the current requirements may not be valid at the launching date.I would also suggest starting a spreadsheet for the cost of everything,using current prices and allowing for 3% increases each year.by year 13 or 14 the numbers may be quite alarming but that would require a skilled and committed boatbuilder.The need to earn money to live on may put the date even further away,which doesn't help.

 

[fcfc]

I am surprised of the planned budget. A mere single harken winch for a sailboat that size is over 14000€ Winch self-tailing 2 vit. Radial | Harken Marine , manual, alumunium, 2 speed. Not electric, Not hydraulic, Not 3 speed Not brass.

 

[fcfc]

Just the price of 4 toilets, with all the plumbing associated (seacock and valves, water heater, black water tank, shower pumps, ...) will be significant. Marelon Full-Flow Ball Valves - Forespar | Fisheries Supply This is just a single vavle.

 

[Rumars]

Rumars, I dont see how that would be the case a solid steel box (not considering the gain in density filling gaps with lead), a 150mm x 300mm x 18m is already 10.5 tons, this can be made as the keel line stringer.
Cheers,
Vinicius

Because the hull you copied wasn't designed to have a long thin ballast spread over most of it's lenght, it was designed to have a centrally located ballast. It is a canoe body, not a long keeler. Inside ballast would have to go in boxes in the middle of the hull, approximately where the original keel was located. This means the ballast is short spanning only a few floors. You want to keep the ballast as low as possible because you already moved it up significantly from its original position thereby reducing its effect, so the ballast can't be very tall.

Weight location and distribution is key to stability and behavior at sea. All inside ballasted boats exhibit the same traits, they are heavy because the ballast ratio has to be increased to be effective (reduced lever arm) and they have smaller angles of vanishing stability. The goal is to bring this angle over 90°, so you don't get rolled over by a knockdown. However 100-105° is all that you can hope for with this kind of boat.

You really need to examine your SOR again. Why inside ballast? Why daggerboards? Why monohull? Why 62ft? Etc.

 

[Vinicius Miguel]

Because the hull you copied wasn't designed to have a long thin ballast spread over most of it's lenght, it was designed to have a centrally located ballast. It is a canoe body, not a long keeler. Inside ballast would have to go in boxes in the middle of the hull, approximately where the original keel was located. This means the ballast is short spanning only a few floors. You want to keep the ballast as low as possible because you already moved it up significantly from its original position thereby reducing its effect, so the ballast can't be very tall.

Weight location and distribution is key to stability and behavior at sea. All inside ballasted boats exhibit the same traits, they are heavy because the ballast ratio has to be increased to be effective (reduced lever arm) and they have smaller angles of vanishing stability. The goal is to bring this angle over 90°, so you don't get rolled over by a knockdown. However 100-105° is all that you can hope for with this kind of boat.

You really need to examine your SOR again. Why inside ballast? Why daggerboards? Why monohull? Why 62ft? Etc.

Thanks for the explanation Rumars.
I appreciate your input.

Two things I don't want to compromise are the boat's stability and its capability in shallow water.
My second option was twin keels, based on your considerations, which appears to be a more attractive option.

Cheers,
Vinicius

 

[Vinicius Miguel]

Hello wet feet and fcfc,
I appreciate your input.

I need to clarify a few points here, as you are starting to speculate on things I never mentioned I would do.

First, as I mentioned in my initial post, this is a lifelong project, so I cannot design a boat that will not serve me in 5-10 years.
I also have friends and family that I want to host, which means that, whether I do commercial work or not, I will have guests at some point. However, that is a good point. If I decide at some point that I am tired of the tech industry and want to charter my boat to secure my retirement income, why not?

About the budget and execution plan:
I did not say at any point that this boat would be fully finished before I move into it; quite the opposite, I stated that this project will be executed in a series of milestones.
My main priority is to transform the boat into a liveable space as fast as possible; for that, I am willing to compromise on comfort. Which means:

1. Only one head will be installed.
2. Only one bedroom will be fitted.
3. The galley will be fitted enough for my needs.
4. The boat will not have a mast, rigging and sails installed. As you pointed out, a significant portion of the project budget.

There are other cost mitigation details I am not entering yet. For example, I am designing all the electronics for my boat, including relay controllers, MPPTs, and other systems. Just on that, I will be saving easily $50,000. However, that is a subject for the future, when I have the designs of those systems ready to show.

Cheers,
Vinicius

 

[BlueBell]

I would love to, since carbon steel is very cheap, but I think the risk of corrosion is too high, in my opinion.
There is also the issue of needing heavy and expensive machinery to form shapes.

Strip planking composite with vinyl ester GF is what I estimate to be a good balance between labour and investment in machinery.

Resin infusion, although requiring meticulous planning for execution, is a highly effective method for glassing the wood core.

Good points you raise.
However, epoxy glass would be much preferred over vinyl ester.
Corrosion can be easily abated in steel construction.
From your dialogue thus far, I suspect a catamaran would better suit your needs (SOR).

 

[fcfc]

I suggest you read this book : Principles of Yacht Design: Larsson, Lars, Eliasson, Rolf, Orych, Michal: 9781472981929: Amazon.com: Books

You can omit chapter 7 Foiling, and 11 High speed hydrodynamics.

Of primary importance , I would say all the remainder, but specially 4 Hydrostatics and stability , 13 Hull construction and 15 Scantlings. Understanding that scantlings will give you some construction weight of the boat , that will bring you back to 4 , until all figures weight and stability match = Appendix 1 main particular Appendix 2 weigh calculation and Appendix 3 STIX

 

[fallguy]

I think the OP is in love with the volume and displacement offered by the monohull, but he really needs to recognize tradeoffs.

The cat will be safer at sea and probably lower operating costs due to higher efficiency. Takes more work to build, but not too bad even at 200%. Maybe higher slip fees, but gonna be pricey for a 70’ slip either way. Cat can run shallower.

The monohull offers more volume at a minor lower cost per unit volume. But poorer seakeeping. More of the living spaces are closer to the waterlines; here the cat wins.

Either vessel would be best built by others in a reputable shop overseas where people work for $3-5 an hour. You cannot compete as a single person against those rates. Take your hourly pay and ration it. If you make 60 and hour; you can pay 12 men to work on your hulls. Get the boat built, then fitout by you will take 36 months.

Your problem is survey and insurance. You cannot find a surveyor or insurance for the project that is to span 5 years. For the beginning, you will have none. After survey of a mostly completed vessel; you can find insurance. To insure as a builder is a different animal. My project spanned 5 years and I did all the work on my private property and no insurer would cover it until Bristol Survey.

 

[Vinicius Miguel]

I love cats, but building one is like building two boats and a bridge. My initial idea was a cat, but after considering the building effort (watching Delos 2, for example), I turned to DS monohulls.

Offshoring the construction to Asia would require me to be there inspecting the build; I would not trust an unsupervised build.

Also, after witnessing the drama with HH, would you consider outsourcing the most critical part of the build?

Anyways, I have to be near the CET time zone for working purposes. So, the southern EU is the best bet for me.

 

[Rumars]

Two things I don't want to compromise are the boat's stability and its capability in shallow water.
My second option was twin keels, based on your considerations, which appears to be a more attractive option.

Cheers,
Vinicius

You need to go back to he basics. What's "shallow water capability" for you in numbers or what does the boat need to be able to do? Let's take the Garcia Exploration 60 at 35t displacement, it's board up draft is 1.5m. The Sauvage Expedition at 33t is advertised by the designer at 1.1m draft, but the client says 1.3m draft.
So what's the target light and loaded displacement of your hull and target draft? What anglemof vanishing stability is sufficient for you to feel safe?