Replacing wooden seats

For issues common to different models of DaySailer.
Except Rigging and Sails.

Moderator: GreenLake

Replacing wooden seats

Postby Guest » Mon Jul 31, 2000 7:52 am

All of the DS I's I have seen have a pair of front facing wooden seats located just aft of the cuddy. I think they are a pain in the a%$ and lead to a lot of shin bruises for the crew. Yet, if they are removed, something has to be done to build in an extension of the seats along the rails. Has anyone done this?

Ken Cobb (kcobb-at-bspmlaw.com)
Guest
 

Postby Guest » Mon Jul 31, 2000 9:02 pm

These wooden seats ( I've always called them thwarts) are the only thing that gives side to side support to the centerboard trunk and to the whole center of the boat. They ( the seats and the thwarts) take a lot of stress when hiking hard and when trailering on bumpy roads. I arrived at a recent race and found out that our utility cut ridden streets here in DC had popped the screws out on the port side flotation tank.

Chris Lewton (clewton-at-erols.com)
Guest
 

Postby Guest » Tue Aug 01, 2000 8:18 am

>>I arrived at a recent race and found
>>out that our utility cut ridden streets here in DC
>>had popped the screws out on
>>the port side flotation tank.

So THAT'S what's been unscrewing my seats! I guess I owe the kids and wife an apology :)


J.T.Ellis (parrothead-at-messageasap.com)
Guest
 

Postby Guest » Tue Aug 01, 2000 9:19 am

Okay, I get the idea that the seats provide lateral support, but is it really necessary support?. They are so close to the cuddy that the foredeck that I would think the thwarts would be redundant of the lateral support provided by the cuddy deck. Also, didn't the later DS models II and III do away with the thwarts and leave the cabin floor unemcumbered all the way to the door to the cuddy?

I am further skeptical about the structural necessity for the thwarts because they aren't all that securely attached, the way you think they would be if they were really necessary. By the way, my thwarts also pop up when trailered, but all sailboat owners have a few loose screws anyway.

Ken Cobb (kcobb-at-bspmlaw.com)
Guest
 

Postby Guest » Tue Aug 01, 2000 8:42 pm

I have an old DS1 with the same shin-breaker. I am also reluctant to remove these seats because it is the one source that provides lateral support to centerboard trunk. Mine are loose until I start sailing hard. E

Eric J. Nelson (nelsonjnelson-at-msn.com)
Guest
 

Postby Bob Hunkins » Wed Aug 02, 2000 12:27 pm

At this year's North American Championship regatta, the The Day Sailer Class measurer reported that there have been questions regarding the removal of the thwarts. Because they do provide a significant amount of structural integrity, A rule explicitly prohibiting the removal of the thwarts will be included in the next revision of the Day Sailer One-design measurement rules. Doing so will make the boat illegal for one-design racing.

Even if you don't race, you shouldn't take the thwarts out, since they do indeed provide a lot of structural support. When the boat is sailing the force being exerted at the chainplates by the shrouds tends to pull the hull into a narrower shape. The thwarts prevent this.

Bottom line - don't remove the thwarts, you may compromise the stuructural integrity of the boat, make it illegal to use in sanctioned regattas and reduce the value of the boat drastically.

Good advice for anyone considering modifications to the hull is to look at the one-design measurement rules for the Day Sailer, and if you have questions, contact the class measurer BEFORE you start making modifications.
Bob Hunkins
Site Admin
 
Posts: 378
Joined: Fri Aug 13, 2004 7:37 pm
Location: Fleet 25, Houston, Texas

Postby Guest » Wed Aug 02, 2000 12:41 pm

The responses above to my original question are a great example of how terrific this forum is. I and perhaps others would have removed the thwarts in ignorance of the ramifications if the above posters had not been available to shed their light on the subject. Thanks, guys.

Ken Cobb (kcobb-at-bspmlaw.com)
Guest
 

Postby Bob Hunkins » Wed Aug 02, 2000 12:46 pm

Agreed! This forum is invaluable!
The beauty of the Day Sailer is you are allowed to tinker with it quite a bit, compared to other one-designs. But the downside is that you can get yourself into trouble by tinkering with parts that ought not to be messed with.
Bob Hunkins
Site Admin
 
Posts: 378
Joined: Fri Aug 13, 2004 7:37 pm
Location: Fleet 25, Houston, Texas

Postby Guest » Sun Aug 06, 2000 2:37 pm

I sail my DS1 without the thwarts. I have however, braced the c/b trunk at the forward end by bolting alum sq. tubing to the trunk and fixing it to the cuddy above. This not only braces the c/b trunk but also ties the hull together top to bottom, reducing the narrowing of the hull due to shroud tension. My boat, #4000, has been this way since new in 1970. I had #2289 before this one and took the thwarts out of it too. The guy I sold it to has continued the configuration (since'76) and has had no problems. The load from the c/b is greatest at the fwd end and thats where my bracing is. I think this makes the boat much easier to move around in which is why I made the change. . At the NAC's this year there were two boats racing without thwarts, one won the Presidential Class with no protest.

Unfortunately there is a contingent in the DSA that wishes to make the removal of thwarts illegal. I can't understand why, as the removal can't possibly make the boat go faster. The original owner of my boat won the North American Championship regatta twice 30 yrs ago with the boat in configured this way so its not like this is a new idea. The group that wants the thwarts in seems to believe that the one design nature of the DS will be destroyed if they continue to allow removal of thwarts. The current class Measurer has asked to have a rule passed banning the removal of thwarts. I hope sanity prevails.

Seems to me that if we must have a rule about c/b trunk bracing, we should have one like the one about the fwd bulkhead in DS1's where its OK to remove it if alternate bracing is installed.

Bob Torson (safehbr-at-pioneer.net)
Guest
 

Postby Guest » Wed Mar 13, 2002 8:04 pm

DO NOT REMOVE THE THWARTS !!! The above example is not valid, the rules have changed in the last 30 years. Bob Hunkins is correct, that the class officers are rewriting a rule to make this issue clearer. The thwarts are uncomfortable sometimes, but they provide necessary structural support. Every sailboat design with the same Centerboard trunk design as ours uses this same method. Thistles, Lightning, ETC........ These yacht designers and engineers would have come up with some other method, if there was a better way.
Daysailer By-Law 3 sec 5.4 "For DS class yachts manufactured with wooden seats, the original seats may be replaced with wood or fiberglass provided the original seating areas and dimensions are manintained." This rule applies to "3" digit boats, whose wooden seats have rotted. This rule seems to clearly indicate that the size and shape must be maintained. And this would include the Thwart area.

If you still want to remove the thwarts, do so, but try this before sailing. (I take no responsibility for what will happen)
Dry launch the boat in a grassy area and step the mast.
Tip boat on its side, and tie the mast to the trailer.
Fully extend the CB.
Have you and your crew get on the board like you would to recover from a capsize.
I do not believe that the 90 degree joint at the bottom of the CB trunk will hold up without cracking.



Phill Root (ds2543-at-msn.com)
Guest
 

Postby Guest » Wed Mar 13, 2002 11:01 pm

Phill you are all wet! It has been legal for over thirty years to remove the so-called thwarts. The rule you quote does not refer to these. My first boat< #2289, sailed allover the West Coast in the 70's with the c/b trunk braced at the forward edge where it is closer to the c/b pivot and thus providing better support to the c/b trunk. This configuration was pioneered by Chuck Gorgen the class champion in '72 and '73. The rules say plainly "any form of internal bracing is allowed".

Bob Torson (Safehbr-at-pioneer.net)
Guest
 

Postby Guest » Thu Mar 14, 2002 8:19 pm

For all who are reading this, be advised the three past class measurers agree that thwart removal has always been illegal.

Phill Root (ds2543-at-msn.com)
Guest
 

Postby Guest » Fri Mar 15, 2002 12:36 am

Although it is with trepidation that I disagree with the Northwestern Regional Vice Pres. of the DSA, it is my understanding that at last summer's annual meeting of the Assoc. the question of removing the thwarts was discussed. " Amendment 2: 5.17 Thwarts (the structural members, usually wooden, that laterally tie the upper centerboard trunk to the seats) as designed by the licensed builder shall not be removed. This proposal was one vote short (thus not passing) the necessary 2/3 majority, thus boats are permitted to remove thwarts. We strongly recommend that this is not done, as the thwarts are an integral part of the structure and strength of the centerboard trunk" (Quoted from the "notes from the President" in the Winter 2002 Day Sailer Quarterly)
Now, if I had a DS I instead of the DS II that I have........I would definitely keep the thwarts in place! They were put there for a reason, and although they may be a tripping hazzard, they do need to be there. If they were not needed for strength, Cape Cod Shipbuilding would not be installing them in the new Day Sailers. In answer to why the DS II and DS III do not have the thwarts, this is because the cockpit structure on those boats takes the place of the thwarts, the cb trunk is braced by fiberglass angle "iron" sections securely laminated to the underside of the cockpit sole.

Rod Johnson,"SUNBIRD" (rjohnson24-at-juno.com)
Guest
 


Return to Repair and Improvement

Who is online

Users browsing this forum: No registered users and 18 guests