displacement cat v displacement mono

[tcm]

depends on the sort of boat of course. There are lots more fishing boats that are cats, and the pupose of those boats is to catch fish, stable platform and so on.

But for some other boats most certainly the form is important.

Seakeeping? - Especially for smaller boats based (or in the style of ) mediterranean, sea keeping not a whole heap of an issue cos you only go out on nice calm days. For better and better seakeeping, get a biggger or even bigger boat. But with a cat, regardless of size, it still looks a bit urgh.

 

[hobiecat]

So the raggies are right. Powerboating is a penis thing then. I will send you another good looking cat to pin up to your bedroom wall with the Birchwood.

 

[Gludy]

I actually think it is largely an image thing - i do not want it that way but it is.
I also think you are right about sea keeping for the reasons you state.
Jowever, its different in the Bristol Channel ... not that many calm days.

 

[andyball]

>> Offshore high performence and efficient powercats are in fact very narrow>>

The mc30's pretty narrow for example - like about a foot less than say a sealine 29, which combined with an empty space in the middle that's... quite big actually, I'd say the "extra" accomodation of a cat might be a bit less than extra in this case.

Also, if a sealine 29' or similar weighed 2 tonnes instead of ,say 3.5T w/one engine? - it'd probably go faster on less power & be more economical - like a motorcat - er?. So is a motorcat loads lighter 'cos it's narrower & has less hull? or are they built lightly?

Have looked at 40+ cats & found accommodation impressively wide in the high flat bit (obviously) but overall less useful than many monohulls, esp pokey narrow cabins in the sides.


So for me, the mc30 goes impressively well with small engines - esp. at displacement speeds , but could do with actually being as wide or greater than a monohull - not possibly designed down to a price.

 

[tcm]

No need to get all huffy. It's a simple fact that by it's very nature, catamarans have a more clumsy form than a mono. Yep, loads of advantages of cats but hey don't look as good.

 

[zeros]

The engines go someway to explaining the weight differential- surely?

 

[andyball]

maybe? but take a smaller beneteau flyer 750 open - weight w/o o/b is 1880 Kg according to bennny, add two etec 50's - as per motorcat gives 2200Kg - 200Kg more than the MC30, but for a much shorter almost open boat.

I still think they're light.

 

[hobiecat]

Accommodation of motor catamaran is usually better than equivalent sized mono but I agree - not much. I am always surprised when people comment how much more space there is down below . Layout has disadvantages and advantages like most boats.

Sealine is a planing boat so it is difficult to compare. My basic non designer understanding is that planing boats are built to resist going forward until they get on plane so they are very inefficient at lower speeds and pound at higher speeds. Probably would not improve Sealine performance too much if built lighter.

Probably due to the reasons outlined by gludy which i found most helpful - from experience I can tell you any catamaran benefits tremendously from being built light which I guess is opposite thinking to displacement mono. Planes are good examples of being light and expensive and if they built them like monos they would not fly. MC is one of the very few cats which follows this philosophy. Light and small power. The cost of building lightweight composite is at least 3 times more in labour so it cannot be said it is built to a price. Guess it saves a ton in weight. Many of the displacement cats are not composite and therefore heavy - so they do not perform quite as well. Extra beam has impact on perfomance and prevent towing.

I notoced a lot of confusion about weight. A lump of oak v light modern composite bullitproof materials. The latter is the stronger It does make it confusing as it turns previous arguments on their head. I used to sell on basis weight of boat justifies its cost - now i have to do the opposite.

I still stand by my thoughts at the moment based on general experience. Planing mono is overall better than planing cat. Displacement cat better overall than displacement mono and is this why commercial operators are moving this way.

 

[hobiecat]

Sorry - did not mean to get huffy. A cat can be made to look good. If there had been a mere fraction as much spent on development of cats as on monos we would have some real sexy cats on the water by now.