Mari Cha: Unique Movable Ballast System

For those interesed in the variations of canting keel technology the various systems are all described in detail under this section of the forum except the unique solution devised by the Mari Cha design team. Mari Cha is shown under “Turbocharged IACC boats”(she is not an IACC boat) in the General Discussion section of this forum.
Most canting keel boats need extra lateral resistace when they go upwind to make up for loss of eficiency when the keel cants. Mari Cha has a unique solution: they don’t use the canting keel upwind! It is locked in place and water ballast is used to stabilize the boat on a beat. Off the wind they lose the water ballast and cant the keel! They cannot use both at once or the rigs would break!
This solution means that upwind they cannot point as high as a boat equipped with CBTF yet they have somewhat less wetted surface off the wind. It also eliminates the danger of damaging the forward rudder or a daggerboard if they were to hit something.
This is a solution not practical for models since a model canting keel will extend much farther to windward than on Mari Cha and water ballast would be much less effective due to scale effect and the required narrow beam for a model…

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

Doug… I’m not trying to be a argumentative pr#ck here, but take another look at the shots Dick L. posted.
Sails are close hauled… keel is canted.
And why so much rail meat with water balast and canting keel?

Dick Carver

Dick, as was pointed out by Will a C&C 40 something will take 10 guys on the rail. Mari Cha is 140’ long and because of the requirements for most records sails must be handled with “normal” winches not power winches. That is apparently the crew required to do that 24 hrs a day …Twenty 160lb crew weigh 3200 lbs; upwind Mari Cha can carry 20,000 lbs of water ballast…If you scaled up the rail meat required on the C&C you’d find that, proportionately, Mari Cha has much less crew on the rail.
Crew is as good a source of movable ballast as you can find outside of a canting keel or water ballast on a big boat–or any boat for that matter-and the crew can move side to side AND fore and aft!
The info on how they planned to use the keel and water ballast is from the design team as reported in part two of the review of the boat on the Daily Sail.And it makes sense: using the keel upwind would be foolish if they were really trying to point because as the keel cants it loses much of its effectiveness. That doesn’t mean they can’t sail high with just the keel and no water ballast it just means that if they do they are not trying to point…Probably did it to illustrate the canting keel and had to head up and use a lot of sail to get that picture ?

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

Dick, you should take the time to read the stuff I’ve written more carefully as well as the stuff written about Mari Cha. This is one big boat and the reasons for not using CBTF could be many. Whether or not Mari Cha uses CBTF in no way reflects on the validity of CBTF! The designers chose this system (no canting keel upwind-their words)for reasons that are best left to them to explain in detail but one thing they have said publically is that the scale of the boat weighed heavily in their decisions.For instance, they did not choose a schooner rig because they liked schooners or because it was more efficient than a sloop rig(it is NOT) they chose it because the crew would still be able to handle the sails with normal winches instead of power winches-a requirement of the rules for breaking the records they are after. The fact that they will not be doing much upwind sailng in their quest to break records was a major factor in choosing the system they have.
CBTF is definitely the fastest form of canting keel system if you put in more or less equal amounts of upwind and down wind racing. There is no other canting keel system that allows as good a VMG upwind as does CBTF-none-period.
If you were to analyze a boat that was to be designed to sail fast upwind and downwind then CBTF makes the most sense. Open 60’s-- so far at least- use twin asymetrical daggerboards with their canting keel and are optimized for off the wind sailng . The designers of Mari Cha say their solution is to not cant the keel upwind–their words not mine. On smaller boats up to 90’ feet it has been conclusively shown that a canting keel is faster than water ballast by a number of designers. And in boats from 40’ to 90’ most of the newest offshore boats are using CBTF including the Schock 40,two new maxZ86’s and Genuine Risk a new 90 footer.
One thing is fact : a canting keel boat MUST have some form of additional lateral resistence when sailing upwind whether CBTF or not: EVERY single canting keel boat to date has either: CBTF, twin asymetrical daggerboards,a single daggerboard(not very efficient unless gybing) or wings(specially designed) on the keel bulb to make up for lost keel efficiency as the boat heels EXCEPT Mari Cha. And that is because her designers say the canting keel will not be used on a beat but will be locked in place…
Weeds are a concern of any model sailing with more or less vertical fins whether CBTF, fixed keel or canting keel/daggerboard…

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

CBTF is the fastest of all the canting keel systems upwind since it is the ONLY one with the facility to dial out leeway!! And it is about equal with other canting keel systems off the wind with the retractable daggerboard boat being closest in certain conditions.
Mari Cha like many Open 60’s before her is OPTIMIZED FOR OFF THE WIND SAILING since her whole reason for being is to break speed records at sea. Open 60’s spend most of their time on reaches and runs–same thing.
Weeds are the most humorous thing you have brought up; you’ve tried to make it seem ,at least in your first post, that weeds are the particular problem of canting keel,CBTF or hydrofoil equipped boats!!! As your picture demonstrates so well ANY boat with a vertical fin can snag weeds!!!

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

In lakes where there are a lot of weeds
I would assume that it would be common sense not to sail boats with vertical fins whether 1, 2,3,4 or whatever. We had to move our sailing site when the weeds became race killers but the EC-12’s are still sailing in the same location.
EC-12’s are the best boat that I know of for weed infected areas and are great fun to race.
If you are in a heavily weeded area don’t buy a boat with one or more vertical fins-buy an EC12!
As to weeds being a reason not to do a CBTF boat–thats ridiculous; I would assume anybody anywhere would take the time to know the area where they are going to sail–high performance boats don’t do well in weed filled lakes–common sense it seems to me.

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

This thread started off talking about Mari Cha IV, and although it has digressed into a discussion of weeds, I have an update on Mari Cha that I wantred to share. Seems like it belongs here…

Mari Cha has unofficially broken the 24 monohull distance record on her maiden passage across the atlantic. As of 7:30 this morning she had sailed 505 nm in the previous 24 hours. The record will need to be ratified by the ISAF before it becomes official, but that is usuallly just a formality…

http://www.sailinganarchy.com/general/2003/marichaIV24.htm

It looks like they are continuing to smash their own record and may have ticked off as much as 525 miles in 24 hours as of 11:30 am. We will have to wait and see how high the new record goes.

Of interest this is virtually the same spot on the earth that Illbruck set the previous record. Nothing like having a 5 to 6 knot push from the gulf stream to help your speed over ground, eh?

You can follw her progress here: http://www.mari-cha4.com//frameset.php

Will Gorgen

Three cheers for Mari Cha!! Not only the fastest monohull, the fastest schooner, and the fastest movable ballast boat in the world!
Guess that puts fixed keel boats in the realm of antiques?! At any rate she’s sure showing what a canting keel boat can do…now all we need is a 140’ CBTF sloop made of the newest undiscovered fiber!! wow!

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing

Congratulations Mari Cha! Fastest monohull across the Atlantic west to east!

Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing