I have been looking at a 77 O'day 20 of the newer design with the fractional rig and the absence of any mast support post. Does anyone know if there is any kind of reinforcement to the deck to support the compression load of the mast? It is difficult to determine if there is any additional support between the headliner and the deck. Several other boats with this design have a more obvious means of support (i.e. bridge beam across the cabin headliner under the mast). Is anyone aware of any failings? Have there been any owner modifications to either repair or reinforce this area? Any thoughts on what to check for? Thanks for your time.
Oday 20 FR Mast Support
- Thread starter RunTimeError
- Start date
Hi there RunTimeError,my nameis Jeff McGee,I have a 1976 O'day 20 and will tell you that there is no interior mast support,George O'day designed this boat to take the compression loads associated with HARD sailing with larger folks sitting atop the cabin.All compression loads are transferred laterally to the hull combing whic is reinforced to handle the loads of the 400 lbs of ballast which is directly under the loaded area. Feel free to pick my brain on this boat. I am a retired Merchant Marine Captain with AUX.SAIL Endorsement, and operated an 87 Ton Three Masted Schooner for six years.
Thanks Jeff for your reply.
There are a number of small cruising sailboats that have eliminated the mast support post in the cabin to provide a more open layout, maximizing the space in a small sailboat. The Capri 18 and Precision 18 come to mind. The Precision 18 used a robust beam spanning the width of the coach roof to shore up the compression loads of the mast and transfer them to the hull. The Capri 18 used two smaller mast support posts on either side of the head compartment supporting a beam between them and directly under the mast to transfer the compression loads directly to the cabin sole.
The FR O’Day 20 does not have any obvious reinforcement directly under the mast unless there is something between the deck liner and the deck of any significant thickness. I have noticed some small bulkhead(s) between the cabinet tops and the underside of the side decks reasonably in line with the lateral areas of mast support.
The FR O’Day 20 I am looking at appears to be strong enough as I move about over the cabin top. My concern is how much load it can take. I have seen the boat sail from a distance and it looks to be tender and perhaps over canvased. My inclination would be to put a back stay adjuster with some purchase to bend the FR mast and flatten out the sail to depower it somewhat. I was wondering if this would be too much compression load for the mast support design. Any thoughts, or are my depowering ideas without merit?
BTW, do you know what the driver was for the rig change from the former mast head to the fractional rig (FR) design? The changes I have noted (in addition to the rig and sail area) are, a change in draft, change in ballast, change in the cabin sole (former MH was flush while FR has slight keel protrusion into cabin), and removal of foredeck hatch (although since this was forward of the mast on the coach roof top it was probably removed to stiffen the deck to help support the mast). Any other changes I missed? Look forward to your reply.
There are a number of small cruising sailboats that have eliminated the mast support post in the cabin to provide a more open layout, maximizing the space in a small sailboat. The Capri 18 and Precision 18 come to mind. The Precision 18 used a robust beam spanning the width of the coach roof to shore up the compression loads of the mast and transfer them to the hull. The Capri 18 used two smaller mast support posts on either side of the head compartment supporting a beam between them and directly under the mast to transfer the compression loads directly to the cabin sole.
The FR O’Day 20 does not have any obvious reinforcement directly under the mast unless there is something between the deck liner and the deck of any significant thickness. I have noticed some small bulkhead(s) between the cabinet tops and the underside of the side decks reasonably in line with the lateral areas of mast support.
The FR O’Day 20 I am looking at appears to be strong enough as I move about over the cabin top. My concern is how much load it can take. I have seen the boat sail from a distance and it looks to be tender and perhaps over canvased. My inclination would be to put a back stay adjuster with some purchase to bend the FR mast and flatten out the sail to depower it somewhat. I was wondering if this would be too much compression load for the mast support design. Any thoughts, or are my depowering ideas without merit?
BTW, do you know what the driver was for the rig change from the former mast head to the fractional rig (FR) design? The changes I have noted (in addition to the rig and sail area) are, a change in draft, change in ballast, change in the cabin sole (former MH was flush while FR has slight keel protrusion into cabin), and removal of foredeck hatch (although since this was forward of the mast on the coach roof top it was probably removed to stiffen the deck to help support the mast). Any other changes I missed? Look forward to your reply.
Thanks Jeff for your reply.
There are a number of small cruising sailboats that have eliminated the mast support post in the cabin to provide a more open layout, maximizing the space in a small sailboat. The Capri 18 and Precision 18 come to mind. The Precision 18 used a robust beam spanning the width of the coach roof to shore up the compression loads of the mast and transfer them to the hull. The Capri 18 used two smaller mast support posts on either side of the head compartment supporting a beam between them and directly under the mast to transfer the compression loads directly to the cabin sole.
The FR O’Day 20 does not have any obvious reinforcement directly under the mast unless there is something between the deck liner and the deck of any significant thickness. I have noticed some small bulkhead(s) between the cabinet tops and the underside of the side decks reasonably in line with the lateral areas of mast support.
The FR O’Day 20 I am looking at appears to be strong enough as I move about over the cabin top. My concern is how much load it can take. I have seen the boat sail from a distance and it looks to be tender and perhaps over canvased. My inclination would be to put a back stay adjuster with some purchase to bend the FR mast and flatten out the sail to depower it somewhat. I was wondering if this would be too much compression load for the mast support design. Any thoughts, or are my depowering ideas without merit?
BTW, do you know what the driver was for the rig change from the former mast head to the fractional rig (FR) design? The changes I have noted (in addition to the rig and sail area) are, a change in draft, change in ballast, change in the cabin sole (former MH was flush while FR has slight keel protrusion into cabin), and removal of foredeck hatch (although since this was forward of the mast on the coach roof top it was probably removed to stiffen the deck to help support the mast). Any other changes I missed? Look forward to your reply.
There are a number of small cruising sailboats that have eliminated the mast support post in the cabin to provide a more open layout, maximizing the space in a small sailboat. The Capri 18 and Precision 18 come to mind. The Precision 18 used a robust beam spanning the width of the coach roof to shore up the compression loads of the mast and transfer them to the hull. The Capri 18 used two smaller mast support posts on either side of the head compartment supporting a beam between them and directly under the mast to transfer the compression loads directly to the cabin sole.
The FR O’Day 20 does not have any obvious reinforcement directly under the mast unless there is something between the deck liner and the deck of any significant thickness. I have noticed some small bulkhead(s) between the cabinet tops and the underside of the side decks reasonably in line with the lateral areas of mast support.
The FR O’Day 20 I am looking at appears to be strong enough as I move about over the cabin top. My concern is how much load it can take. I have seen the boat sail from a distance and it looks to be tender and perhaps over canvased. My inclination would be to put a back stay adjuster with some purchase to bend the FR mast and flatten out the sail to depower it somewhat. I was wondering if this would be too much compression load for the mast support design. Any thoughts, or are my depowering ideas without merit?
BTW, do you know what the driver was for the rig change from the former mast head to the fractional rig (FR) design? The changes I have noted (in addition to the rig and sail area) are, a change in draft, change in ballast, change in the cabin sole (former MH was flush while FR has slight keel protrusion into cabin), and removal of foredeck hatch (although since this was forward of the mast on the coach roof top it was probably removed to stiffen the deck to help support the mast). Any other changes I missed? Look forward to your reply.
Glad to hear back from you, between the inner hull liner and the outer deck skin is marine grade plywood which is quite stong when new, and as long as the wood stays dry,its very reliable. I weigh 180 lbs. and use a cane when I walk. When onbard I don't bother with the cane and sort of hp on my good leg all over the boat,literally all over the boat.I go out with a couple of guys who each weight 220lbs. each and their favorite spot to girl watch is one on each side off the mast with me in the cockpit, and she sails very well even with their combined mass that high up over the center of gravity. As you look in the main hatchway, you notice a perfect arch(which is the strongest shape geometricly you can use) the small braces or bulkheads are original epuipment on this boat,I still have them but want to replace them with some nicer stock wood.
Nice call on depowering the main via the backstay adjuster, I do that when it gets sporty here on my lake. The easiest way to make her more stable in high winds(Over 25MPH) I raise the centerboard a little which moves the center of lateral resisistance farther aft and allows her to sideslip a little during gusts, she sails very well with the board up completely on a reach of anykind only when close hauled is the board an absolute must.I find the 400lbs ballast is plenty for the rig. FYI this autumn I went out when the winds wer forecast 20kts.steady with gusts, so off I go looking for a good day of some spirited sailing. As the day progressed the wind built to 30kts with gusts,so I duck into a small cove and roll two turns of reef into the main(the reefing being done by pulling back on the boom and roll it two revolutions,then push boom forward to lock into place),as I head back out into the full wind I feel much happier with the centerboard halfway down and I got the old girl out of displacement mode as the transome broke free of water,I touched 14 knots on a broad reach and as I round up to enter my cove the wind shifted and gusted to around 40kts. I thought,oh crap, she immediately got knockeddown to her masthead laying about a foot above the water.My rudder is in the air and I'm standing on the portside cockpit combing with one foot and ballancing my bum leg on the boom(I can see into the cabin and the cabin window looks like the glassbottom boat but is not leaking)., meanwhile the boat has begun to right herself and brings the bows into the wind wher she shakes her sails at me in disgust.This has only endeared the design to me,as I held on inertly,the boat did what it was supposed to do eg.stand up,float,and take care of passengers,she did this so well.I have been through some eight to ten knockdowns in my life and this boat does it well.
As to the change from a masthead ri to a fractional rig,remember that this was the seventies and the idea of a "high aspect rig" was emerging, this is a fairly high aspect for the time.By utilizing an FR the top of the mast is more free of stays and shrouds which can make flying spinnakers a real bear. the size of the jib in the FR is sufficient to provide a great slot effect for the main.
The protrusion into the cabin sole allowed for the larger centerboard to be used in addition to the 400lbs. exterior lead ballast, its nice to be able to go anywhere there is 15 inches of water,and sail up to a beach and step onto dry ground,great for overnight trips back ster right up to beach and step over transome.
Nice call on depowering the main via the backstay adjuster, I do that when it gets sporty here on my lake. The easiest way to make her more stable in high winds(Over 25MPH) I raise the centerboard a little which moves the center of lateral resisistance farther aft and allows her to sideslip a little during gusts, she sails very well with the board up completely on a reach of anykind only when close hauled is the board an absolute must.I find the 400lbs ballast is plenty for the rig. FYI this autumn I went out when the winds wer forecast 20kts.steady with gusts, so off I go looking for a good day of some spirited sailing. As the day progressed the wind built to 30kts with gusts,so I duck into a small cove and roll two turns of reef into the main(the reefing being done by pulling back on the boom and roll it two revolutions,then push boom forward to lock into place),as I head back out into the full wind I feel much happier with the centerboard halfway down and I got the old girl out of displacement mode as the transome broke free of water,I touched 14 knots on a broad reach and as I round up to enter my cove the wind shifted and gusted to around 40kts. I thought,oh crap, she immediately got knockeddown to her masthead laying about a foot above the water.My rudder is in the air and I'm standing on the portside cockpit combing with one foot and ballancing my bum leg on the boom(I can see into the cabin and the cabin window looks like the glassbottom boat but is not leaking)., meanwhile the boat has begun to right herself and brings the bows into the wind wher she shakes her sails at me in disgust.This has only endeared the design to me,as I held on inertly,the boat did what it was supposed to do eg.stand up,float,and take care of passengers,she did this so well.I have been through some eight to ten knockdowns in my life and this boat does it well.
As to the change from a masthead ri to a fractional rig,remember that this was the seventies and the idea of a "high aspect rig" was emerging, this is a fairly high aspect for the time.By utilizing an FR the top of the mast is more free of stays and shrouds which can make flying spinnakers a real bear. the size of the jib in the FR is sufficient to provide a great slot effect for the main.
The protrusion into the cabin sole allowed for the larger centerboard to be used in addition to the 400lbs. exterior lead ballast, its nice to be able to go anywhere there is 15 inches of water,and sail up to a beach and step onto dry ground,great for overnight trips back ster right up to beach and step over transome.
Hi Jeff, thanks again for the detailed response. Although I would hope not to challenge 40 knot gusts, your posts have given me some confidence in the boat in terms of stability. –Never thought to put two 200# guys on the cabin top to keep it from bowing up??
We recently had a rare hard rain several weeks ago and I noticed the boat in question had some water dripping from the mast step bolts inside the cabin. The owner thought it was possibly leaking around the wiring where it comes up through the deck and mast step and connects inside the mast. I hope to get a look at that to see if there is any rot, or at least be part of the rebedding process. I did walk all over the cabin top today and there are no soft spots typically indicative of delamination of the deck to the core material.
The lake where I sail just north of Phoenix is typical of inland lakes with light to moderate breezes most of the time. Moderate breezes are often accompanied by gusty shifty winds which keeps you on your toes. My former MO was to run with big canvas and bleed off sail during the gusts. These days it’s more like preparing for the gusty times with reefs and enjoying the performance of the boat in lighter conditions with perhaps marginal sail. Cheers,
We recently had a rare hard rain several weeks ago and I noticed the boat in question had some water dripping from the mast step bolts inside the cabin. The owner thought it was possibly leaking around the wiring where it comes up through the deck and mast step and connects inside the mast. I hope to get a look at that to see if there is any rot, or at least be part of the rebedding process. I did walk all over the cabin top today and there are no soft spots typically indicative of delamination of the deck to the core material.
The lake where I sail just north of Phoenix is typical of inland lakes with light to moderate breezes most of the time. Moderate breezes are often accompanied by gusty shifty winds which keeps you on your toes. My former MO was to run with big canvas and bleed off sail during the gusts. These days it’s more like preparing for the gusty times with reefs and enjoying the performance of the boat in lighter conditions with perhaps marginal sail. Cheers,
I'm resealing every throughdeck fitting with countersinking and Butyl Tape method and cleaning and polishing everything as I go(my pulpit is sitting in my livingroom this instant)and all hardware and aluminum is in excellent shape.I also plan on replacing all rivets in the mast and boom this winter,as well as stripping off all antifouling and 5 new coats of barrier epoxy,then three coats of antifouling,new hatch rails,handrails,and researching replacing the teak toerails with aluminum slotted rails.and then?????
The shape of the centerboard was changed when the switch to the fractional rig was made, CB became shorter and had a longer "chord" that is fore and aft width if viewed In down position, hence the CB trunk now extended slightly above the cabin sole. I suspect that the change to fractional rig might have been to add sail area as the original masthead rig appears a bit "small" to my eye, also the taller mainsail would be more efficient at producing power than the smaller masthead main, rig styles on racing boats were trending more towards large main - small jib designs around that time as well. I drop the jib as the first "reef" on my DS II, same should work for the 20 (fractional rig), however, on the older masthead rig... dropping the jib (even if using the "working jib instead of a genoa) would seem to reduce sail too much for efficient sailing. With a rig like that the first reef would be reducing the main (using roller-reefing or slab-reef) and keeping full working jib.
I have a 74 oday 20 and on mine you can pull the spring loaded boom out and roll the mainsail onto the boom to reef it in. I also purchased a used thistle jib which I use as a "storm jib" when it gets windy/gusty. It is very sable and sails nicely when I do this.
Realizing that I am replying to a very old post...I too have a "76 O'Day 20 fractional rig. All my stays, forestay and side stays, are as tight as possible, and there is quite an aft mast rake, and there is a bit of play in the side stays. My thought is that the tp of the cabin has sagged a bit where the mast step is. My thought is to measure in the cabin from just underneath the mast step to the cabin floor, then release tension on the stays and measure again. This will tell me if the cabin top is being depressed when I tighten the stays. I was then thinking of placing some sort of vertical pole in the cabin under the mast step to prevent the sagging. Any thoughts would be appreciated.
