Buying a Cat - advice needed

[Talbot]

At the size craft you are looking, I dont think there is a cat with a long keel, they all use dagger boards.

[fastcat435]

Originally Posted by Gludy

I am used to self learning autopilots but on power boats - I forget about their ability to tack a sailing boat!!

So another question - in actual cruising terms - what advantages and disadvantages do dagger boards offer over a fixed keel?

How much work is involved with using them?

They must be more prone to damage from floating objects?

First the advantage of daggerboards
1.slightly higher pointing
2.when sailing downwind less resistance
3. In stormy conditions it can be safer since the boat can slide sideways better.
Disadvantages.
1.more use of space inside the boat
2. extra weigth
3. more expensive to build
4. much more damage prone
5. biggger chance of leaks
6.more work to sail and not really handy for single handed sailing

Greetings

Gideon

[Sunspot Baby]

Seriously, why do you need 50' for the two of you? There are many excellent cats that are very sea worthy without spending so much.

We cruise on a 38' cat and are quite comfortable even with another couple visiting for a few weeks at a time.

While larger boats are nice but they have accompanying down sides when it comes to docking and maintenance.

George

[fastcat435]

Originally Posted by Talbot

At the size craft you are looking, I dont think there is a cat with a long keel, they all use dagger boards.

Contrary to what you think there are very few 50 ft cats that have daggerboards.
Most have keels and only a handfull use daggerboards like the
Outremer
Catana
Gunboat
Freydis

and all other Frensch , South African and English have keels
Greetings

Gideon

[Talbot]

Originally Posted by fastcat435

3. In stormy conditions it can be safer since the boat can slide sideways better.

Always assuming you have pulled the boards up and have them well secured!

[fastcat435]

Originally Posted by Talbot

Always assuming you have pulled the boards up and have them well secured!

Yes off course otherwise it really becomes dangerous

greetings

gideon

[Gludy]

Are daggerboards optional on the FastCat?

I agrree most 50 footers do not have daggerboards eg New Discovery, BraodBlue, Privilege etc.

As regards to why we like big boats - the simple fact is we have becomes used to them and like our luxuries. The bigger boats can manage the washing machines, dish washers, etc etc with less trouble.

I also have a video studio etc on board - and we will spend many months at a time on the boat. All our boats have been in the 60 foot Mono class to date - all power of course and we do like the room.

[Nordic cat]

Originally Posted by fastcat435

3. In stormy conditions it can be safer since the boat can slide sideways better.
Greetings

Gideon

This idea of being able to slip sideways to avoid tipping over is often mentioned, but in fact more knowledgeable people say that this is not an issue, as the wave moves so fast that it is in fact impossible to accelerate the boat before the wave has passed under both hulls.

I think a 5 m wave will pass a 7 m wide boat within a second or so, and would in fact support the boat on the bridgedeck on the way through.

I think Woods and Kelsall make reference to this on their sites.

The area of one daggerboard and a LAR keel would probably also be comparable. Unless the wave is at exactly 90 degrees relative to the daggerboard, the boat would probably twist around the board as well.

Nevertheless, I wouldn't have my board fully immersed in extreme conditions anyway.


Regards

Alan

[Nordic cat]

Originally Posted by Gludy

Are daggerboards optional on the FastCat?

I agrree most 50 footers do not have daggerboards eg New Discovery, BraodBlue, Privilege etc.

As regards to why we like big boats - the simple fact is we have becomes used to them and like our luxuries. The bigger boats can manage the washing machines, dish washers, etc etc with less trouble.

I also have a video studio etc on board - and we will spend many months at a time on the boat. All our boats have been in the 60 foot Mono class to date - all power of course and we do like the room.

A 50 foot cat will probably have more room than a 65 foot monhull, but if you are going to load it heavily, make sure you get one that can handle the load and retain good sailing performance. So an initially lightish boat with a good immersion figure (kgs/cm) that also retains good bridgedeck clearance when loaded.


Regards

Alan

[Gludy]

It is one of the reasons I need a large boat.
The amount we load it is about fixed so we have to get a big enough boat to take it.

Any load will cost performance - it seems

[Evan]

Get yourself a copy of Chris White and Gregor Tarjan's books on cruising multihulls. Chris's is older but good background material and Gregor does a good job with more modern designs.

Don't artificially say "I have to have a boat in 3 months". Take the time it takes to do your research.

The skinny boats and/or boats with big rigs

Outremer
Catana
Gunboat
Freydis
Fastcat? (sorry Gideon I haven't read any reviews or been on your boat...)

are going to be the fast boats in the list mentioned so far.

Daggerboards are not that big a deal with floating objects. You hit those with the bow (I know). They are more hassle if you go hard aground are more susceptible to damage. But they do improve performance.

FP's polars are for 1 wind speed (20 knots) and I would guess an empty boat but they don't say on their web site. Peak speed of 10 knots in 20 knots of wind for a 48 cat doesn't excite me. Our 40' Richard Woods cat does more than that without a spinnaker. Typically 11-12 knots on a reach with just genoa and main - but it's a light boat.

[Talbot]

Daggerboards do improve performance.

There is little evidence to support that view for a cruising catamaran, but I wouls accept that the statement is true for those at the higher end of the performance envelope. IIRC There is only one cruising cat that was available as either LARS or dagger board (low aspect ratio keel). This was studied at length and the conclusion was that there was little real difference in performance overall. One performed better in some circumstances but was balanced by the other's better performance in other areas.

I personally prefer the LARS approach because it provides better directional stability, and is better for drying out. But that is personal preference only.

[Gludy]

I have read the Chris White book cover to cover.

I really do appreciate that I am being told a mix of many things - that is what I am sorting out.

[Nordic cat]

Originally Posted by Talbot

There is little evidence to support that view for a cruising catamaran, but I wouls accept that the statement is true for those at the higher end of the performance envelope. IIRC There is only one cruising cat that was available as either LARS or dagger board (low aspect ratio keel). This was studied at length and the conclusion was that there was little real difference in performance overall. One performed better in some circumstances but was balanced by the other's better performance in other areas.

I personally prefer the LARS approach because it provides better directional stability, and is better for drying out. But that is personal preference only.

This is the reason that I'm having both on my new boat! Chris White's Atlantics have something similar.

Daggerboards are primarily for windward work. On my present FP, I could do around 95 degrees between tacks at best in flat water using a non-standard self-tacking jib that i could sheet further in than the standard genoa. With the genoa 100 degrees was typical at around 15-16 knots of wind.

I have just rerigged it with a (taller) rotating wingmast and new main and self-tacking jib, and can get around 88-90 degrees now. With good daggerboards i'm confident that low to mid 80's would be achievable.


regards

Alan

[Gludy]

One thing I am doing is actually trying the boats out to test the claims against the practice. Its not just theory that I am looking at.