fishing trawler to pleasure conversion

[TANSL]

Of course, if ballast is necessary, I would put solid, fixed, permanent ballast. It is necessary to study the most relevant, or most normal, load condition, and define the amount of ballast and its position, which manages to comply with all the stability requirements and the greatest comfort for the passenger. As simple as that.
Regarding fuel consumption, have you taken into account that not only the main engines consume energy? There may be many other consumers.

 

[James Wellington]

Fair enough, you prefer solid ballast some prefer liquid, like on that $4million Seaton 60 boat. Me, I'm open to suggestions. Some, like those Cape Horn trawlers, I think, have twin bilge keels with lead as ballast, and you can park them on the beach to check out the bottom too!

 

[fallguy]

The concept of ballast here does not seem to be understood by you well James.

Ballast is an offsetting mass. It is used to offset other weights or the lack of them. For each amount of ballast; you are giving up something else.

It isn't a free lunch.

Domino, previously owned by the Dufours, traveled 53,000nm under their helmsmanship. These miles, in the longliner, based on our crude estimates, is roughly 53,000 • 6 gallons or 318,000 gallons of fuel. Using $5@, the fuel costs are 1.6M versus Domino herself fuel costs of $265,000. Let's say they got 3nm/gallon, then their costs were $100,000 and the longliner at 6x would be $600,000 for fuel. But you get the picture? You are considering spending $500,000 more (likely more) for the same fuel for a slower boat with 110% more draft. Now, you do get more space onboard; that is true. But it is hard to justify the boat for recreational use when so many other better options exist that are ultimately safer by reaching ports faster.

Why not put that 500k-1.5M into a better boat?

 

[James Wellington]

I do know those points about ballast, and so do those boat builders who use the various types of it. Some like lead, some like water, etc.
We dont know the milage of the Seaton 60 or the Damen boat.
I like the Damen boat because of its full displ hull, that it is a hybrid electric one already, that it has a huge flat roof for solar panels, that its main deck can be closed in. All that has been done already. I had also asked members if they know of a boat that has all that already, and nobody points to any, nor can I find one. I would just prefer alu instead of steel. We know there are fast boats....we like slow and ugly ones.

 

[rberrey]

The company I retired from had a custom barge built for a ringer , the bow consisted of three sections / tanks for water ballast where we could drain them and tow the barge up for a heavy lift .The water ballast worked well for what it was designed for , the tanks stayed full to maintain the designed water line . If I were to have a large boat with water ballast it would have a number of smaller tanks with baffles that I could pump dry or keep full , one or the other , never half full . As weight is added to or subtracted from , the boat weight could be adjusted at a point by draining or filling a tank . I suspect that by the time you pay for change orders you could pay someone to design what you want , or contact a smaller shipyard building work / fishing boats and build out one of their production hull,s .

 

[James Wellington]

Thanks. Yes and what I've been discovering so far too. Separate tanks and is switched around, as some do with fuel tanks as well.

 

[Rumars]

Well, if you want better answers you need to describe your operational parameters in more detail.

The Damen hull is designed for hauling capacity, so the big question is if you actually need it, and for what. Typically holds get converted to accommodation, but if you don't want that, then you have a big space to fill. Some will be necessarily used for ballast (and you have enough space for even cheap one, like concrete) and food storage is negligible (your stated half a year for 5 people won't amount to more then 2 cubic meter even including packaging). Batteries you can fit as much as you like, but how much makes sense depends on what you use them for. For propulsion the problem is recharging, and solar isn't going to do much. The hull is simply not optimized for low power, even at 5kn in minimal trim its going to take something like 100kW. You can run the numbers, but you can't fit enough panels to give you more then one hour of solar electric running. Hotel loads are another thing, you are going to have enough solar to run air conditioning at anchor without running the generator.

The big difference between the fishing hull and a recreational one is the buildt in total displacement. A recreational one simply doesn't need that amount of weight carrying capacity, so the hull is different. The underwater part is modified to reflect this, regardless of how the topsides are styled.

 

[James Wellington]

Thanks for your reply. The boat already has series diesel electric propulsion. One electric motor, a bit over 400hp, and a big genset, and a bit over 4000 US gallons fuel. Diesel boats get about 25-35 % better milage than straight diesel. regarding space/ ballast, much can be devoted to battery capacity. . Some boats I see have even 300 or 400 KwH of it. Dont know the weiht of that offhand. Then all those solar panels just help out keeping them charged, in addition yo the genset. I have some details in their product sheet, but cant figure out how to upload it here. Maybe could by private email.
Re , you saying the hull is not optimized for slow speed. They say its for 8.5 kts, not sure if down to 5kts would make any difference, but could ask the Dame guys when they respond back..

 

[bajansailor]

James had previously emailed me the product sheet for the Damen vessel - I will attach it here.
Sea Fisher 2007 - Long Liner - Damen https://www.damen.com/vessels/fishing-vessels/seafishers/seafisher-2007-longliner

 

[James Wellington]

Thanks, was going to ask if you would know how to send it! great, now other people can see a bit more!
Also, ITMT, I found out something more about the water of sea water as ballast. It's from another Moen Marin boat, different hull, size etc, but still answers some of the questions raised here. Will try to find it now.

 

[James Wellington]

Update on ballast. This is a differt boat, NABWORK 1575, ...15X7.5m, shorter but wider...1:2. Anyway, it uses seawater ballast, 3 tanks, 2 stern, one in bow. 11m3....2905US gal..
Some here have been making it sound like you cant use seawater, or its crazy schlep around water, yet many boats do.

 

[fallguy]

No!

I never said it was crazy to schlep around water. I said it was crazy to schlep 85,000kg of water or even 85,000kg of water less accomodations in the former hold to get a passenger ship to her lines.

Please do not take kindly, helpful observations and twist them out of proportion. There is a reason for ballasts; even in the ship you found. It is to get the boat to her lines lightship most likely.

But you don't need 187,000 pounds of food onboard..

 

[James Wellington]

How about massive battery banks? That's practical to schlep around, right? Ill bet it is since we know some boats have such.

But you don't need 187,000 pounds of food onboard..

I never said that weight of food.

 

[bajansailor]

The Moen Marine Nabcats do look like very interesting vessels.
Catamarans - Moen Marin https://www.moenmarin.no/en/produkt/catamarans/

 

[James Wellington]

Yes, especially that 1512. Lets hope they send you the tech specs. The monohull one is also interesting......like a big aluminum bathtub, half as wide as it is long....alreadt a dieselelectric hybrid.