Have any of you guys considered going over to the Dark Side...

[Rappey]

I really like this cat.. ignoring the price the ability to cruise at 5knts forever on purely solar is very appealing...
Ive had two small speedboat type cats powered by outboard and for a given hp they are a lot faster than a mono hull and the ride is so much smoother..

 

[penfold]

For a dive boat we looked at a cat, it was a fishing boat, plenty of room, nice and steady, powerful diesel engines one in each side, but watching between the hulls as we approached hull speed the bow wash was hitting the underside of the central span and causing a lot of buffeting , she got to hull speed at less than 1/2 throttle and would not go any faster.
Going through the boat's documents, the builder had taken the plans from a normal mono hull boat, split it down the middle and made a cat out of it, interesting idea and a stable boat but a disaster all at the same time.

No we didn't buy it, after the sea trial we said thanks but no thanks.

It's quite bad that cats generally get a bad name because some have been designed by lazy or ignorant NavArcs(or as you describe not really designed at all).

 

[Bouba]

I really like this cat.. ignoring the price the ability to cruise at 5knts forever on purely solar is very appealing...
Ive had two small speedboat type cats powered by outboard and for a given hp they are a lot faster than a mono hull and the ride is so much smoother..

I like it too, but the reality is if I had two million (plus the rest to keep this vessel) the price of fuel would be the least of my concerns

 

[prinex]

In the never-ending quest to find the perfect boat for longer periods on the med cats always comes up - specially if you cruise / anchor a lot during the summer and dry dock in winter. Then the marina fees would not bite too much .

However even a fat 60ish traditional hull would consume almost nothing at 5kn - a quick calculation (boatdiesel has a power required calculator) for a 16m lwl boat and 54 tons displacement results in 28 Hp at the flywheel to move at 5kn, resulting in 6.5 liters/hour, so a bit more of 1.2 lt / mile.

So even if you travel like crazy 4 months at 5kn in the med and cover 2000 miles (40 days of 10 hours travel which is a lot) you are going to be 3400 Euro out of pocket which is a dent in the general scheme of costs of such an adventure.

And you will have the choice of tons of boats, new or used instead of probably 3 in all the med.

 

[vas]

Just so you know, we aren’t just on the Dark Side, we are planning on the full blackened monty: we are planning going parallel hybrid electric with a 8+ kW solar array.

interesting, do you have circa 30sqm of space to fit all these panels?
f/b and aft/rib area cover?

EDIT: doh! just saw the post I'm quoting is from 2020...

 

[Farmer Piles]

In the never-ending quest to find the perfect boat for longer periods on the med cats always comes up - specially if you cruise / anchor a lot during the summer and dry dock in winter. Then the marina fees would not bite too much .

However even a fat 60ish traditional hull would consume almost nothing at 5kn - a quick calculation (boatdiesel has a power required calculator) for a 16m lwl boat and 54 tons displacement results in 28 Hp at the flywheel to move at 5kn, resulting in 6.5 liters/hour, so a bit more of 1.2 lt / mile.

So even if you travel like crazy 4 months at 5kn in the med and cover 2000 miles (40 days of 10 hours travel which is a lot) you are going to be 3400 Euro out of pocket which is a dent in the general scheme of costs of such an adventure.

And you will have the choice of tons of boats, new or used instead of probably 3 in all the med.

Just been flicking through the current MBY and the review of the Absolute 48. As you say, even a 21t monohull with near enough a 15ft beam did 12l/hr at 6kts, more than 2mpg in old money. Still way more than the 3lph, but not bad. Interestingly, that figure all but doubled at 7.6kts and was almost fourfold at 9.1kts. Presumably would drop lower still at 5kts.

 

[ShaneAtSea]

Fountaine Pajot have to launched a Coupe version of a power cat. Personally i like a flybridge but each to their own

At the recent Cannes Yachting Festival, MBY deputy editor Jack Haines took the chance to tour the Fountaine Pajot MY4S, which was making its global debut.

 

[prinex]

Just been flicking through the current MBY and the review of the Absolute 48. As you say, even a 21t monohull with near enough a 15ft beam did 12l/hr at 6kts, more than 2mpg in old money. Still way more than the 3lph, but not bad. Interestingly, that figure all but doubled at 7.6kts and was almost fourfold at 9.1kts. Presumably would drop lower still at 5kts.

You can play a bit with displacements lwl and so on with this spreadsheet https://www.boatdesign.net/attachments/gerr_shp_formula_compare_with_groot-xls.58071/ - when I had the trawler I could move the 15tons (beam 3.20 mt) at 5.5 kn at around 1 lt per mile, basically using 25hp of the whopping 75hp that the old deutz could deliver.

here g/hph to l/h (from grams/horsepower-hour to liters per hour)

you can play around with hp and lr/hour consumption (gram per horsepower is 200 for diesel).

The Nordhavn N41 which is around 20tons comes with 2x74 hp engines - once you stick to 6-7 knots fuel consumptions becomes a non issue. Also older big Hatteras with 500hp engines are good, you can still run them at 20-25% of load and dont run in the soot / carbon problem.

 

[Portofino]

I think you buy theses things for the floating apartment like spaciousness .Buyers appear engineering wise ignorant.I use that word in the true sense not as derogatory comment .

Still manufacturers have found a rich seem of punters aspiring leisure style types who get mugged with the marketing BS hype .
The lower cost in making means lower power packs fit glove in hand . The FDs will be collecting bigger bonuses the more the products sell .

A nice spin off is indeed the lower consumption .
Slow boats = knack all Hp = low consumption.
But bear in mind the boring ness of long passages and the inability to speed up to mitigate adverse weather .
The time framing of usage if it ever moves .

The weather does cut up in the med from a wind pov .
I would rather gun it at near 30 knots in 3 hrs to Corsica in a morning summer calm ….ANY day to fit my schedule as opposed to taking 18 hrs to do 100 miles + which adds in some night time .

Also pootle about ( yes we do that too ) at 9 knots 55 % load 875 rpm burning under 20 L / hr per side .

The fuel bill is not a massive proportion of the over all cost to fund , I mean the purchase price less depreciation, the TOTAL .
Ok with the fuel side of expenses you see it at every fill up it’s visible unlike the berth + what ever and depo .

And yes as already alluded finding a place when away from your home port in the season .
Its all about the beam .

For me I would major on whats most comfortable passage making and can go out in comfortably in a wider range of sea states .I wouldn’t want the beam / berth restrictions dictating the passage plan / destination choice.
Your boat should not …..tail wagging the dog !

And can if called upon cover 100 miles in 3 hrs …..it’s nice to have that option in the back pocket .
Once you have tasted that nuance it’s hard to imagine passage planning with out .The options plan “B s “ open up .

 

[prinex]

But bear in mind the boring ness of long passages and the inability to speed up to mitigate adverse weather .

Thinks of the rags ... for them planning 6kn from a to b is a pipedream ... and still they are there..

 

[Irish Rover]

Buyers appear engineering wise ignorant.

Could you explain this comment please (in simple terms for one of the ignorant)

 

[ShaneAtSea]

Could you explain this comment please (in simple terms for one of the ignorant)

I think he was referring to someone like me. I want to own a boat but i have no intention of sanding decks or stripping engines.

I own a nice car and i know how to change a tire but if an engine warning light comes on then i'll take it to an expert.

I suspect that the oily rag brigade hate boaters like me. They're the guys who stand near boat ramps to laugh at idiot day boaters trying to reverse a trailer into the water....badly

The "I told you so" crew

 

[kashurst]

I own a nice car and i know how to change a tire but if an engine warning light comes on then i'll take it to an expert.

Good luck with that. There's no hard shoulder on the sea. There is relatively little RAC/Green Flag coverage. By the time a warning light comes on, on a boat it's too late. The wind and tide will decide your fate well before any rescue team turns up.

 

[Portofino]

I think he was referring to someone like me. I want to own a boat but i have no intention of sanding decks or stripping engines.

I own a nice car and i know how to change a tire but if an engine warning light comes on then i'll take it to an expert.

I suspect that the oily rag brigade hate boaters like me. They're the guys who stand near boat ramps to laugh at idiot day boaters trying to reverse a trailer into the water....badly

The "I told you so" crew

Just adding to Kashursts post ^^ .
Some one many years ago told me 50 % of motorboat boat ownership enjoyment is actually fixing stuff .The other enjoyment oh sailing in the thing .

This was a broker from S / S ker Poole driving me to Bournemouth airport to catch a flight home …….AFTER I had instructed my bank to transfer funds .

Turned out right .

Over and above the safety engine room basic stuff it’s just easier .

This year returning from a shopping trip wife pipes up “ teak could do with a clean “.

We had been out every day it was nearly lunch time a nice breeze ……..went to the marina shop spent the next few hrs at it .Teak cleaning and sealing the bathing platform .
Put all the neighbours to shame for the rest of the season .

 

[ShaneAtSea]

Good luck with that. There's no hard shoulder on the sea. There is relatively little RAC/Green Flag coverage. By the time a warning light comes on, on a boat it's too late. The wind and tide will decide your fate well before any rescue team turns up.

Im sure i'll be fine just floating around in Florida. Thats part of the adventure.

I dont plan on going to university to become a marine engineer any time soon but i promise to take it a little more seriously if i attempt a transatlantic crossing

?

 

[Irish Rover]

Just adding to Kashursts post ^^ .
Some one many years ago told me 50 % of motorboat boat ownership enjoyment is actually fixing stuff .The other enjoyment oh sailing in the thing .

This was a broker from S / S ker Poole driving me to Bournemouth airport to catch a flight home …….AFTER I had instructed my bank to transfer funds .

Turned out right .

Over and above the safety engine room basic stuff it’s just easier .

This year returning from a shopping trip wife pipes up “ teak could do with a clean “.

We had been out every day it was nearly lunch time a nice breeze ……..went to the marina shop spent the next few hrs at it .Teak cleaning and sealing the bathing platform .
Put all the neighbours to shame for the rest of the season .

Thanks for the anecdotes but I'm still uncertain what you meant in #49 when you said "Buyers appear engineering wise ignorant". Specifically which buyers were you referencing and on what basis do you label them engineering wise ignorant?

 

[Bluemu]

interesting, do you have circa 30sqm of space to fit all these panels?
f/b and aft/rib area cover?

Yes, we’ll have about that for all the panels.
nearly 10sqm above the cabin, and about 20sqm on the hardtop and back toward sterns.
Those up high will need to be semi flexible to lower the highup weight, which limits to about 20-21% efficient rather than 22-23% panels.