Advice on Beachcat Selection for Rig Test Platform

[Dragon701]

I am interested in testing 4 to 6 different rigs to use on a short-handed, large, light cruising catamaran. One potential challenge for a couple cruising a large cat is the size and weight of the typical main. In my view, this is no problem as long as all works well, but it can be a real issue if there is a failure. Many people have suggested solutions for this: ketch, bi-plane, aft-mast, wing masts, junk rig, Balestron; all are possible. While each has its proponents, I have not seen any direct, data-driven comparisons. There is also a subjective aspect to the decision. For example, ease of use is somewhat in the eye of the beholder.

My plan is to buy two relatively inexpensive and identical beachcats. I will modify one so it can easily switch between the 4 to 6 rigs that I choose, e.g. extra chain plates, structure, line-handling systems. I will use the other as the base line, after adjusting it to account for the weights and moments added to the modified model.

Then, of course, I plan to sail them against each other collecting actual and qualitative data on performance. I will decide which rig I like the best and then scale up to a larger catamaran. I recognize that there may be some scaling issues, but I think that they are surmountable.

My question: which beach catamaran should I select as my test platform?


Some important criteria to consider (in no particular order):

• 17 to 25 feet long: smaller saves $$ on the boats, rigs and sails; larger may be easier to work with and adapt (see the next point)
• Able to take the added weight and structure necessary to test a half-dozen very different rigs
• Fiberglass (not sure that it would be easy to stick things to a rotomolded poly hull, although I can see some ways to avoid the problem, so I wouldn't completely rule them out)
• Simple: highest performance is not the key, but getting the boats in and out of the water has to be relatively easy (I can leave them rigged and in the water for some period of time however)
• Sails well: I am going to spend a lot of time on them; they should be fun; I prefer wings for comfort
• Identical: formula classes do not work unless the boats are the exact same version from the same manufacturer
• Easily available: obviously, my focus is on the rigs, so extra expense in buying the hulls takes away from the budget for rigs and sails

It might be useful, though not essential, to have three cross-beams to more easily accommodate the modifications that I will be adding to the test boat.

Suggestions anyone?

[SaucySailoress]

Um, hate to sound ditzy (but that's nothing new), but have you tried your local sailing clubs to see what's available i your area?

[Event_Horizon]

Hello Dragon, this sounds like a neat little experiment you have brewing. I'm interested to see where this leads and (obviously) your conclusions.

I don't want to give you suggestions so much as...points of contemplation. I would like some more information about the general theme behind this venture.

On what sort of boat do you ultimately plan to implement the--scaled up--rig?

Explain your general cost/benefit analysis. For example, you mentioned a wing mast, which is theoretically the best performer on the list. If you were to seriously consider putting a rotating wing mast on a large cruising cat (30+ feet) you'd just have to accept the fact that you'll need to have every single part of the rig individually fabricated (mast to halyards). You'd also need to add an additional sensor to the top of the mast to read its angle and something clever to solve the tricolor navigation light problem. In addition to that, running the rigging back to the cockpit would require a non-trivial amount of ingenuity as well. Given the hundreds of additional man hours to make this happen, is it still legitimately on the table? (even if it isn't I'd still love for you to test)

How do you plan on actually gathering the data?

Why do you need two boats for testing? Say you are testing a dual mast rig against the 'standard'. If you modify the moment and CG of the 'standard' to match that of the dual mast rig; what are you really testing and what is the point to making that comparison? Beyond that, if you find a way to reliably account for the performance of the cat, if it is reliable it should be repeatable and you shouldn't need to individually race each new rig against the control.

[SaucySailoress]

Originally Posted by Event_Horizon

Why do you need two boats for testing?

Exactly? If you buy a boat from your local club, then you can simply test it against everyone else's (class legal) boats...

Sounds like a lot of fun though. Pics, please!

[Dragon701]

Thanks for the comments:

EH:
This should get some people revved up -- I am interested in light, long and slender hulls and plan an "extra long" boat with a smaller boat's accomodations.

A wing mast is a feasible ultimate solution. Others have solved some of the issues that you correctly point out and I have some solutions too. In my case, it would probably be a "partial" wing with a soft trailing edge. I avoided getting into the rig selection for this post, but might try posting again at some point to hear which rigs people would like to see tested.

Your point about weights and moments is a good one. I am trying to account for the weights and moments of the extraneous gear that I will need on the test boat, not the extra weights of the trial rig configuration; they have to stand :-) on their own. Sorry, that I wasn't clear about this.

I plan to use a data collection package (computer and sensors), while I don't plan to go crazy with it -- at one level, observation will will be sufficient for my purposes. I have access to this.

Finally, two cats should provide faster results. I could use statistics to compare the rigs over time on one platform, but feel that using a reference boat will be faster and isn't cost prohibitive -- one of the boats, at least, won't get modified, so can be sold at the other end for something close to what I paid for it (under the assumption that they were both "second hand" to start with.


SS:
You idea of using my "local" club compatriots as the reference is a good one. I'll consider it.

Thank you both.

[shawnkillam]

I know you have suggested 17 feet and up, but I would suggest you look at the 16 Hobies simply because there are untold thousands around and you could get dozens for the price of a case of beer. I fore instance had three. I gave one away and use the other for parts.
They are more or less designed for two people and will carry four with obvious degradations in performance. They are easily trailerable and parts are readily available. Maximum performance statistics are very well known and there are hundreds of hobie fleets around that would probably provide help or at least a cheering section.
good luck and please add me to the list of people who are interested in your results.
sk

[thinwater]

Originally Posted by shawnkillam

I know you have suggested 17 feet and up, but I would suggest you look at the 16 Hobies simply because there are untold thousands around and you could get dozens for the price of a case of beer. I fore instance had three. I gave one away and use the other for parts.
They are more or less designed for two people and will carry four with obvious degradations in performance. They are easily trailerable and parts are readily available. Maximum performance statistics are very well known and there are hundreds of hobie fleets around that would probably provide help or at least a cheering section.
good luck and please add me to the list of people who are interested in your results.
sk

... but the Hobie 16 deck is probably the trickiest to modify. I would suggest the Prindle 16 or 18 as cheap and practical. The Prindle 16 is so similar in performance to the Hobie 16, you could test them against each other. In fact, many parts are nearly interchangable.

[shawnkillam]

Thinwater is absolutely correct modifying a hobie deck would be a bitch and there really isn't any good way of laying a solid surface across it because it is a series of complex curves. The Prindle would be better but there are probably 1/10th as many hanging about and the owners are less likely to give them away. Matter of fact if you find someone who wants to give away a prindle let me know I'd like one.
sk

[scook1]

I would encourage you to stay away from the Mcgregor line. Although they will probably be cheaper, finding parts is a nightmare! They are much less common. I love mine, but would not wish the challenges that we have had on anyone else.
Spencer

[Bill Burgette]

Try some Nacra 5.8 cats. They have abundant bouyancy forward. As the bow starts to submerge the bouyancy increases and the boat will not "dig in" to the water. If you're planning on some sail changes the Hobie might be out of the question. If the bow gets a little under water the boat will head straight for the bottom and anyone on the trapeze will think they are playing maypole as they are stuck firmly to the jib with feet pointed skyward.

Good luck

[Dragon701]

... for the responses and suggestions. I considered all of the boats that you have suggested and, of course, there is no right choice.

Recently, I purchased two Stiletto 23s (actually one and a half -- one of the boats doesn't have a rig, which is perfect for my purposes). I like the larger size because it allows for the extra paraphenalia that I plan to use on this project.

Thanks again!

[boatman61]

Before investing in a 'wing mast' take a look at the Wharram Tiki Gaff Wing Sail.. the mast is round alloy tube and the sail fits round it with a sleeve which zips up.
Basically it performs pretty much as a wing mast does.... at a fraction of the cost... and no 'Boom' to worry about..