Gaff Rig Gooseneck Height

[dlane83]

Hello everyone,

I just signed up for this forum since I am considering the purchase of a catboat and the Com-Pac cats have a lot of useful variations to the traditional cat.  Besides the functionality of a catboat, I personally like the look of these boats which leads me to my question,

After looking at a number of different catboats, there is something about the look of the gaff rigged sail on the Com-Pac cats that didn't seem quite right to me.  My conclusion is that it is the height and orientation of the boom.  The booms on Horizon cats are higher off the deck at the mast and the booms are horizontal which requires the gooseneck to be higher than on more traditional cats.  Although I have no experience with the Com-Pac gaff rig, from what I have read on this user group site, it appears the gooseneck slides up and down the mast in the sail slide slot and can be positioned pretty much anywhere including above the Mastendr hinge.  It appears the intent when raising the sail is to raise the boom up to the mast hinge and then use the downhaul after the sail is up if the luff needs tightening  This adjustment would be similar to using a cunningham on a sloop.  Again from what I have read, it appears there is a pin on the hinge assembly that prevents the gooseneck from being raised above the hinge.

I think that the Com-Pac cats would look much better if the gooseneck was kept closer to the deck like more traditional cats.  Since this would prevent the forward hatch from opening while under sail, the boom could still be raised when the sail is down as needed to allow the hatch to be opened when in port.  In order to maintain sufficient cockpit headroom, the boom would need to slope upward toward the clew.  This is exactly the configuration traditional cats use.

Now(finally),  to my question.  I would like to know what you Com-Pac cat owners think about these observations as well as whether you think these cats could be modified with a new sail that would have a somewhat longer luff, a gooseneck (tack) positioned closer to the deck and a clew that is higher than the tack.  Besides giving these cats a better look in my opinion, this modification would add a little more sail area low on the sail which might have the benefit of helping light air performance without affecting heavier air healing.

Thanks in advance for any thoughts you might wish to share.

[CaptRon28]

It's a compromise which works well.

The height of the mast hinge was probably based on trailering ability and crew comfort. Too high and you'd increase the total height of the trailered boat and create overhead clearance problems. Too low and access to the cabin would be even more restricted with the sail and/or mast down. as well as the ability to move around in the cockpit. When I have no intention of lowering the mast (at a marina, mooring, etc.), I use the long pin to keep the gooseneck permanently ABOVE the hinge - which adds some headroom in the cockpit (Not the intended usage by Com-Pac, but it helps). Tilting the boom up would require a higher gallows to hold it, and presents the above trailering restrictions. There are also safety concerns and requirements about not being able to use the hatch in an emergency. A permanent topping lift to hold the aft end of the boom up would not really work on a cat boat - the gaf is in the way when sailing. You'd have to de-rig it first, and have no way of controlling the end of the boom then. I use the throat halyard to hold the boom up if I keep the bimini up with the sail down. But you still have to lower the bimini for a few minutes to get the sail and gaf down.

As long as you're talking about the "look" of the boat, why not use a round section mast with rings to hold the luff? And remove the non-traditional centerboard?  A huge barn door rudder would probably look better too. Of course, all of these "improvements" would negatively affect the boat's performance. Think of the Horizon as an improved modern cat boat. It points nearly as well as a sloop and can get up to around 6 knots in 12+ knots of wind.

[dlane83]

Thank you Ron for taking the time to respond,

I agree with your comments that, for the most part, the changes Com-Pac has made to the traditional cat are good.  That is why I am considering one.  Let me clarify, if I can, my point about the sail configuration as well as make an additional point.

SAIL:  Keep in mind that I have no actual experience with any of the Com-Pac cats and specifically with their rigs so, for example, I don't know exactly what the long pin that you and others have commented about is.  With that said, my comments about changing the sail configuration do not necessarily have anything to do with the height of the mast hinge.  In my view, that can stay exactly as Com-Pac has designed it. 

I know there is a pin that is used to lock the hinge closed.  I believe that pin is located on the front of the mast.  It is not clear to me whether the long pin you referred to is a separate pin on the back side of the mast that has something to do with the boom gooseneck.  Anyway, the change I was suggesting was simply to cut the sail with a lower tack, but with the clew at the other end of the boom the same height as on the current sail.  This would mean the following. (1) The look of the sail would change and would look more like a traditional cat, (2) the height of the boom over the cockpit, especially the aft end of the cockpit, would not change to any significant extent, (3) the sail area would be increased slightly but would be located low so as not to appreciably affect healing moment in heavier winds, (4) the luff from the boom to the gaff would be somewhat longer (perhaps a foot).  In other words if you were to compare this sail to the standard sail, this modified sail would be exactly the same with the exception that the boom would attached at the mast closer to the deck and, as a result, the boom would no longer be parallel to the deck.  Instead it would be about a foot lower at the mast than at the clew end of the boom.  When taking into account the length of the boom, that wouldn't be much of a slope, but would in my opinion, make the boat look more catly if you know what I mean.  My original question was whether the mast and boom configuration would allow this to be done or if the boom must be kept at its current height due to the way it is held in place with respect to the mast hinge or not.

Now, you mentioned the high aspect ratio rudder which, I agree, is much more efficient than, and preferable to, the normal barn door rudder of the traditional cat.  From what I gather, they can produce serious weather helm.  Nonetheless, I am one who likes the look of the barn door rudder.  While I wouldn't want to change the Com-Pac rudder (see question below), I did have a thought that a false barn door shaped applique could be attached to either side of the rudder housing that could go just a few inches below the waterline to create the look of a barn door rudder without the disadvantages of a true barn door rudder.  This could be done so the Com-Pac spade could still swing up in between the two sides of the false rudder applique.  I don't know if you have ever seen the Alerion 19' cat, but it is interesting that the designer, Gary Hoyt, essentially did exactly that.  He designed a shallow barn door rudder with a swing down high aspect ration rudder that could be raised and stored in a cavity that was built into the barn door rudder.  You can think of it much like a keel centerboard.

Lastly, I am hopeful you can help me out with another question I have from reading some of the posts on Com-Pac cats.  I was reading that some people have apparently retrofitted their cat with a more efficient fold up rudder that is available on the aftermarket.  From a picture I have seen, it looks like the tiller might go above the transom rather than through the slot in the transom, but I'm not sure about that.  Nonetheless, my question is - is this a modification people with older boats are doing or is this rudder an improvement to the current rudder design, even on new boats.  The information I read seemed to say that the standard Com-Pac rudders can stall under certain circumstances and leave something to be desired despite their improved aspect ratio.

I hope this has clarified my points about the sail and hope you can help me further with my question about the rudder retrofits that I have read about.

Thanks, Don

[capt_nemo]

dlane83,

For a reasonably nice looking boat and ease in quick rigging/derigging at the launch ramp - get a Com-Pac Cat.

Then, modify it to your heart's desire, as I have done with my Sun Cat!

I use a homemade Nylon Drifter set "flying" in light to moderate air and have even made a Nylon Mainsail which is also set "flying" in light air over the stowed Main. I've recently installed a Bowsprit that extends 4' beyond the hull stem complete with Bobstay and Whisker stays. I needed a platform and larger foretriangle area with which to experiment and play with various headsails. To counteract the forces involved at the masthead I added additional shrouds from the same chainplates to the masthead. All of this work was designed, fabricated, and installed by me, and I loved every minute of it!

Here are a few photos which speak for themselves.

capt_nemo

[CaptRon28]

Don -

You probably can increase the luff and hold the boom further down, but that would seriosuly hurt the marginal headroom that the stock Horizon already has. Forget about ever using a bimini too. And I doubt if it will actually help performance. Most of the power is coming from the back half of the sail well above the deck. Adding maybe 6 inches of sail forward and low won't get you much, if anything. You would be blocking the forward hatch as well - a real safety problem at anytime. The ABYC standards call for a usable excape hatch. I'd rather raise the sail to get more of it into better air. The throat halyard gets raised to the point where the gaf swivel is touching the block. Then I adjust the gooseneck downhaul to the wind conditions.

The long pin is at the back of the mast and keeps the gooseneck either down or up. The safety pin is at the forward edge of the hinge and it's just that - to hold the mast vertical while you connect or detach the head stay. I would not consider using just the safety pin to sail. You will lose the rig.

The barn door rudder was invented because these boats with no real centerboard needed something to control leeway. It takes the place of the board and will steer the boat at the same time, but at what expense? You've got to greatly increase the rudder angle to compensate for no board or fin and that can really kill performance and pointing ability. It's drag at that angle would also increase weather helm and will stall. By the way, the Horizon comes with a decently shaped rudder. Only improvement I can see would be to get one that goes vertical (up) while trailering. The stock one is limited to 90 degrees and sticks straight out in back if you leave it on. The boat comes with wheel steering as well. I'm not sure how well the Sun cat rudder works.

Get one first and then play with it. It looks damn good just as it comes out of the factory. An improved and modern cat boat. I can point better than many sloops, and outrun some as well. But note that cat boats don't sail like a sloop. Don't event think of trying to get the boom on centerline while close hauled. It won't like it.

[dlane83]

Capt Nemo & Ron,

Thanks for your thoughts. 

Captain Nemo, your modifications look great. It seems to me that cutting sails is not something for an amateur.  I wouldn't be able to do that.  Is the light air performance that bad that you need the light air main and jib?

BTW, do you also own a Jeanneau 42 DS?  It looks like you own a home in Florida.  Where do you sail the HC and the Jeanneau?

Captain Ron, your response provided good detail and clarification about the HC sail and boom.  The only reason I was interested in lowering the boom at the mast was for looks, not performance.  With a Horizon Cat, as well as a Sun Cat, both with a sizable cabin house, I don't think the boom will be all that much lower over the cockpit when the boat is under sail.  The only noticeable change could be when tacking or jibing, but again I think it would be small.  When the sail is down, the gooseneck can be stored at any height as I understand it.  WHAT I NEED TO CONFIRM IS WHETHER THE BOOM CAN TECHNICALLY BE LOCATED AT ANY HEIGHT ON THE BOOM WHEN UNDER SAIL AND SPECIFICALLY UNDER THE

As for the rudder, my intent was not to change the rudder or replace the standard spade rudder.  Instead, I was talking about making a false rudder applique that would mound to either side of the standard rudder post from an inch or two below the waterline up and in the shape of a barn door rudder.  This would not change the efficiency of the rudder and the spade could fold up the same way it does now in between the two RUDDER applique panels.

[CaptRon28]

Don -

Technically the boom gooseneck can be located at any height on the mast's aft slot. If I don't pull the throat halyard all of the way, the gooseneck can easily wind up under the hinge. I wouldn't want to do that though - don't like getting hit in the head with the boom and the sail works better in clean air. As far as the height of the rest of the boom, since there is no topping lift, it finds it's own level based on wind and mainsheet tension while under sail. The gallows holds the aft end of the boom when the sail is down. The above applies to the Horizon and probably the Sun cat as well.

I think Capt Nemo and I are both down in Charlotte Harbor (Punta Gorda, Port Charlotte, etc.) on the SW coast of Florida. I sail a 28 foot Telstar trimaran down here. The Horizon lives in NJ. I may sail over and check out their regatta this weekend.

[dlane83]

Capt Ron,

You are getting closer to what I am looking for.  I agree with all the comments about boom height in the cockpit when lowering the gooseneck, but what I am talking about is having a new sail cut that would have a longer luff (and, thus a lower tack/gooseneck), but with a clew that is cut to be the same height as the standard sail.  This would result in an upward slope to the boom that would probably vary no more than a foot along the entire length of the boom.  The clew end of the boom would, therefore, not be any lower than the standard sail and the use of the gallows would be no different either in my opinion.  Since the lower boom would mostly be over the cabin, I suspect a bimini could still work since it is further back in the cockpit and the boom height at that point probably wouldn't be noticeable lower.  When the sail is down, the height of the boom at the mast could still be adjusted (raised) to allow for normal use of the forward hatch (on a HC) as well as boom tents etc..  My intention, btw, is to have a sail made with these changes rather than purchasing the standard sail on a new boat or replacing an older sail on a used boat.

It is clear to me at this point that the boom can slide up and down in the mast slot from the mast hinge (or possibly higher) down to the deck, but my major concern remains whether the mast slot below the hinge housing is strong enough to handle the loads that can develop at the gooseneck when under sail.  Another way of getting to my concern is to determine whether the mast hinge assembly, which appears to be made of stainless steel) is designed to have the gooseneck slid up into it (possibly up to the long pin people have referred to) in order to provide additional strength/support for the gooseneck.  I can envision that this might be done to prevent the boom from pulling out of the mast slot or at least from distorting the slot in the aluminum mast when under heavy load.  I have heard of an instance in the past where the boom pulled out of the mast on a small sailboat when it was hit with a strong gust from a weather front.  Since I don't have one of these boats yet and haven't seen the rig, these exchanges have helped me to zero in on the question(s)/concern(s) I have.  Unfortunately, this may have been more painful for those of you trying to answer my question than it has for me. 

While on this subject, I believe I read on a post somewhere that there is an option (or it is possible) to have a longer gaff boom and thus a larger sail than the standard sail.  Do you or anyone reading this know anything about this?

Thanks for your indulgence,  Don L

[CaptRon28]

Don -

Since the boom will be at an angle, and if you can get the gooseneck maybe 8 inches under the hinge, I estimate that the a bimini at the forward edge of the cockpit will probably be around 4 inches below the boom. In other words, you will need to make a lower bimini. That could present a problem if you or any crew is taller than about 5 feet 8 inches. The stock bimini is maybe 1 inch lower than the boom with the sail pulling up.  My Horizon is up in NJ and I'm not, so these are just estimates. With the sail down and the boom in the gallows, the bimini cannot be used. If you're leaning more towards the Sun cat, these numbers will be even worse.

Unless you sail in an area with consistant lower wind speeds, I would not increase the length of the boom or the area of the sail. You could easily get overpowered. The standard Horizon setup can take 18 or so knots under control without having to reef. I think I've done about 20 or so, which required some real concentration to keep it under control. The longer boom will also change the balance of the sail and boat. You will be moving the center of effort aft, introducing more weatherhelm.

Get one, try it out first. You might like it exactly as designed and built.

[dlane83]

Ron,

I think you may have misunderstood me on one point.  The question I asked about a longer boom was not in reference to the main boom, but to the gaff boom.  That might not be the correct terminology, but I am talking about the boom at the top of the sail.  The comment I thought I read somewhere was that someone had had a new sail make with a longer gaff boom which increased sail area aloft.  I assume you haven't heard of that being done on these boats.

Don

[CaptRon28]

Sorry - one is called a boom and the other a gaff. Never heard the term gaff boom. But same result - you could easily overpower the boat, change the sail balance, create additional weatherhelm, overstress the rig, etc. Maybe no problem if you're sailing in an area where the wind is always less than 10 knots, but it could be one if its more than that. You might be better off overall with light air sail(s) as pictured above. One note about the gaff itself - the owners manual has a very clear warning about using a winch handle to raise the peak halyard. Sounds like the designer is worried about overstressing the rig.

As I said before, get the boat first and then figure out if you even want to modify anything. I really don't see a need for it. It sails as well as any 20 foot cat boat should.

[dlane83]

Ron,

Thanks again.  Your advice of trying the boat out before making changes is a good one and I would tend to do this unless I buy a new boat and want Com-Pac to delete something like the sail so I can have one cut with a change like I have discussed (lower tack).  But, I wouldn't do that unless I had researched the change and was confident it wouldn't affect the boat negatively.

Don