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Post by Daniel on Feb 22, 2021 6:10:24 GMT
Hi Don, It may be useful if you could provide some clarification on the use of screws for construction. Your recent facebook post indicates that screws in the structure would be a requirement for class registration. But based on builders blogs, in a number of cases of builds underway, screws have been used temporarily to hold pieces in place while epoxy cures. If I'm not mistaken, #78 built to completed hull by Kolibri has not a screw in it.
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Screws
Feb 23, 2021 8:17:37 GMT
via mobile
Post by Severin Hummer on Feb 23, 2021 8:17:37 GMT
Hi Don, It may be useful if you could provide some clarification on the use of screws for construction. Your recent facebook post indicates that screws in the structure would be a requirement for class registration. But based on builders blogs, in a number of cases of builds underway, screws have been used temporarily to hold pieces in place while epoxy cures. If I'm not mistaken, #78 built to completed hull by Kolibri has not a screw in it. It also makes no sense that some use 300 screws, others only 20 if all screws have to stay in there should also be a rule how many screws are needed and how far apart
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Screws
Feb 23, 2021 19:50:25 GMT
Post by peterbrumby on Feb 23, 2021 19:50:25 GMT
Weight difference won’t make a difference when we get sailing. That weight difference will be insignificant compared to people’s different decisions on kit selection, spares, food etc. Then add-in sail plan, course choice, ability to steer, ability to be awake when wind shifts happen etc.
I personally feel more secure having the screws left in there, as the designer requests. And maybe I will now push a little harder into that dark cloud up ahead lol. ; )
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martellmarine
Junior Member
Husband & wife team building boat #71.
Posts: 61
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Screws
Feb 24, 2021 5:46:29 GMT
Post by martellmarine on Feb 24, 2021 5:46:29 GMT
At this stage we do not know why the screws are specified. It clearly is not because the boat would fall apart if the screws were not there. I think you will find that the screws are there because of the 'ethos' of the whole project. It is meant to be a simple build requiring limited skills and tools. Screws are much cheaper than clamps. Less tools to invest in and easy just to leave them in rather than add time taking them out. Convenience. Drilling a holes and driving a screw in is an easy skill to learn. Good for amateur builders. Using screws and leaving them in WILL save you time...
However, some builders have time as well as clamps... plus a different skill level.
Nowhere in the plans is it stated that you should cove or fillet any of your joints. Yet we see builders doing this. Why? It is because it primarily strengthens a joint, and in fact, it is a common wood/composite boat building technique to substitute wooden cleats for epoxy fillets of varying sizes. However, fillets or coves are not weightless. I am guessing that if every joint in the boat was properly filleted there would be 200 lineal meters of coves/fillets. I am also guessing that would weigh more than the screws used to put the boat together!
If you screw (and leave them in) AND fillet/cove your boat, it will weigh more than just screwing. If you have no screws but fillet/cove you will probably weigh the same as just screws. I don't think people should 'major on a minor.' If we are going to talk about screws then we should also talk about fillets.
I personally do not want to leave screws in because they tend to ruin paint jobs. Its a cosmetic thing for me. If you fill a screw hole with a filler that is not the same density as the wood around it then it will expand and contract at a different rate. You will eventually see small bumps where every screw is. That may not be a problem for the Okoume boats with 1200grams of glass and a thick bog layer, but I am using meranti with just 500 grams of glass. I have seen this time and again through my boat building career. I want to take pride in building my boat and I want it to look great for the longest time possible. I know how to do this. No screws in the hull!
I beg to differ about weight. If I can save 30-40kgs in the build then I look at that as the ability to carry more water or spares of food or... something to ease life aboard for an extended period of time... or help with sailing with two people! I also think you will find that weight will matter enough though that eventually there will be minimum limits set for the class.
Cheers
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Post by renaud on Feb 24, 2021 6:10:14 GMT
Hello in the Blog of building Hull 1 it says on 03.July 2020 : We cover the screw heads with an epoxy putty. To obtain a putty, we thicken the epoxy resin with microbalons or wood pollen. The screw heads are covered with epoxy putty. To obtain a putty, we thicken the epoxy resin with microballoons or wood pollen.
This means the screws stays in, I presume.
@don, could you please clarify about the screws ?
For the weight, I hope that every boat empty will be weighted and then if needed added with lead weight fixed in hull to adjust all boat at nearest and acceptable minimum weight (same in all one design class). Then all the boat will be nearly same.
what do all builders think about ?
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Gary.S
New Member
HULL # 111
Posts: 23
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Screws
Feb 24, 2021 8:37:31 GMT
gui likes this
Post by Gary.S on Feb 24, 2021 8:37:31 GMT
Once again agree with all points Greg has made. Once the screw debate is sorted, & hopefully the "no screws" campaign wins, we can all move ahead. If no screws are allowed I will be using minimal screws only to hold the panels in place until the glue goes off. You can screw through small pads so that when the screw is removed there is only a hole from the shank of the screw left to fill. If your frames , stringers , chines etc are nice & fair, the plywood will naturally lay to them so there is no need for lots of screws. Filleting ? I can't see any advantage in doing this on these boats. Another thing i'd like to bring up is that on the builds I am watching, I think just about everyone has put big butt straps on the joins in the plywood hull planking. It appears that the plywood hull planking is only butt joined. I want to scarf my plywood so there are none of these butt straps on the inside of the hull. Is this something I need to talk to the designer about ? That's my two bobs worth Gary.S Boat # 111 Still yet to start , but might start cutting some wood tomorrow
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Screws
Feb 24, 2021 21:35:52 GMT
Post by Joe - Sail No 46 on Feb 24, 2021 21:35:52 GMT
Hi
I left some screws in and took others out, for example the second layer of ply on the bottom of the hull, I used lots of screws to ensure the ply bonded, but took out the screws after as I used lots. Then on most of the frames I left them in. I agreed with all the above and I've just been pragmatic, save weight and be strong!
I only ever used A4 screws as some I could not get out so in that event it did not matter.
Cheers
Joe
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Screws
Feb 25, 2021 11:01:43 GMT
Post by jimschofield on Feb 25, 2021 11:01:43 GMT
Good stuff Greg. All my screws are A4 316 and left in place after epoxying. Partly because I actually like the construction look of it and I'm going to epoxy inside the hull and not paint. I tried removing a few test screws and the heads just came off, epoxy is strong stuff.
When planking, I used strong filler with the epoxy, West 403 and just ran my finger along, to leave a little fillet on everything and to smoothen things out. I did fillet extra in the forepeak, but that's just fear in action.
On the subject of weight, I've just turned the hull, opened my fourth 25KG barrel of epoxy and I used it as sparingly as possible. So I presume weight will vary wildly between vessels.
Jim
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Screws
Feb 26, 2021 23:01:53 GMT
Post by Admin on Feb 26, 2021 23:01:53 GMT
All the screws must stay in if you want 5.80 certification as once people start playing around with screws out, it opens a can of worms..and the designer specifies it, fasteners stay...to use staples is OK as they are left in as well...I have seen first hand people starting to remove screws when it is "easier"..like with epoxy NOT quite off ( True) cause it is too hard after that and heads break off etc...etc etc...it is a designer specification.....The TREKKA BUILDERS BLOG is part of the building instructions to follow from the designer Janusz...Screws are NOT removed. and he has the final say as his specifications are part of the One Design class requirement for a racing boat and certification etc that eventually flows back to potential legal liability..so believe me it is very involved and you as the builder will have to sign a declaration that you have built the boat to the designers build plans and specification?? ..if you cannot sign that declaration, then obviously we cannot certify the boat and Janusz cannot acept responsibility...the parts that are able to be modified are specified, but the things that are not, you should not unless you have written approval from the designer and Janusz will rarely offer that.....so good luck...
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Screws
Feb 26, 2021 23:04:54 GMT
Post by Admin on Feb 26, 2021 23:04:54 GMT
Once again agree with all points Greg has made. Once the screw debate is sorted, & hopefully the "no screws" campaign wins, we can all move ahead. If no screws are allowed I will be using minimal screws only to hold the panels in place until the glue goes off. You can screw through small pads so that when the screw is removed there is only a hole from the shank of the screw left to fill. If your frames , stringers , chines etc are nice & fair, the plywood will naturally lay to them so there is no need for lots of screws. Filleting ? I can't see any advantage in doing this on these boats. Another thing i'd like to bring up is that on the builds I am watching, I think just about everyone has put big butt straps on the joins in the plywood hull planking. It appears that the plywood hull planking is only butt joined. I want to scarf my plywood so there are none of these butt straps on the inside of the hull. Is this something I need to talk to the designer about ? That's my two bobs worth Gary.S Boat # 111 Still yet to start , but might start cutting some wood tomorrow You can scarf the ply but you MUST still put the Butt straps in as they are a structural component of the hull...you can write to Janusz but I know what the answer will be?? good luck ....
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Screws
Feb 26, 2021 23:10:01 GMT
Post by Admin on Feb 26, 2021 23:10:01 GMT
Hello in the Blog of building Hull 1 it says on 03.July 2020 : We cover the screw heads with an epoxy putty. To obtain a putty, we thicken the epoxy resin with microbalons or wood pollen. The screw heads are covered with epoxy putty. To obtain a putty, we thicken the epoxy resin with microballoons or wood pollen. This means the screws stays in, I presume. @don, could you please clarify about the screws ? For the weight, I hope that every boat empty will be weighted and then if needed added with lead weight fixed in hull to adjust all boat at nearest and acceptable minimum weight (same in all one design class). Then all the boat will be nearly same. what do all builders think about ? There will be NO balancing of weights to make all the same weight...you must weigh your structure as explained in the website...that is a requirement of certification...and your keel must be to exact class weight ( Bulb to be advised)....but the hull and deck structure is up to the builder as long as all aspects of the build Design spec are carried out...the weights will vary a little depending on type of ply, and glass, fitout and gear carried etc...the class roll ist to regulate certain things very strictly, but final hull deck weights will vary for sure...but all have a choice of materiels...and it will NOT be a huge factor...but??? good luck
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Screws
Feb 27, 2021 22:17:45 GMT
via mobile
Post by Daniel on Feb 27, 2021 22:17:45 GMT
All the screws must stay in if you want 5.80 certification..., fasteners stay...to use staples is OK as they are left in as well......Screws are NOT removed. ....so good luck... It's not so good luck for #78. The blog shows clearly screws for stringers and hull set with washers for removal; holes where screws were removed; hull screws located and left proud clearly for removal. Not sure if Kolibri or the owner of #78 frequent this site, but maybe someone should let them know they won't be class certified. They may want to halt the build.
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martellmarine
Junior Member
Husband & wife team building boat #71.
Posts: 61
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Screws
Feb 28, 2021 0:05:42 GMT
Post by martellmarine on Feb 28, 2021 0:05:42 GMT
Another thing i'd like to bring up is that on the builds I am watching, I think just about everyone has put big butt straps on the joins in the plywood hull planking. It appears that the plywood hull planking is only butt joined. I want to scarf my plywood so there are none of these butt straps on the inside of the hull. Is this something I need to talk to the designer about ? That's my two bobs worth Gary.S Boat # 111 Still yet to start , but might start cutting some wood tomorrow You can scarf the ply but you MUST still put the Butt straps in as they are a structural component of the hull...you can write to Janusz but I know what the answer will be?? good luck .... Admin Don, are you talking about the kit boat or a boat built from plans? Please note that you CANNOT SCARF the hull panels supplied with the kit as they are designed to be put together with butt straps. The panels are simply not long enough to put scarf joins in. This feature of the kit makes the butt straps "a structural component of the hull." However, if you are not using a kit but are building from the plans instead, you will find that there is NO SPECIFICATION, NOTE OR DRAWING whatsoever stating the joining method for either the hull panels or the bunk longitudinals. The plans ALSO DO NOT SPECIFY what type of join should be used for all of the gunwales, chines and stringers. Although there is a longitudinal piece of 9mm ply down the middle of the deck, there is none noted athwartship for joining the deck panels either! The only reference in the blog about a butt join or a scarf join in the hull panels is here Trekka II Blog simply stating that a scarf is "more difficult" to do and that a butt join and straps are "easier." Even though Trekka II has butt straps THERE IS NO STATEMENT in the blog about butt joins being mandatory anywhere for plans builders (that I can currently see). Builders have rightly assumed for both the kit set and the plans built boats that a scarf join is THE preferred method for joining all of the solid longitudinal timber components, despite no plans specification to do so. Similarly, it is also Logical for plans builders to assume that a properly executed scarf join is THE PREFERRED METHOD of joining the over length plywood panels because there are NO INSTRUCTIONS TO DO OTHERWISE on the plans as supplied, the blog or the builders updates. I don't know if Gary.S is planning on using a kit or wants to build from plans like I will be doing, but it would be great to know if your directive is just for kit builders or also for plans builders as well. Cheers.
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Gary.S
New Member
HULL # 111
Posts: 23
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Screws
Feb 28, 2021 9:38:16 GMT
Post by Gary.S on Feb 28, 2021 9:38:16 GMT
You can scarf the ply but you MUST still put the Butt straps in as they are a structural component of the hull...you can write to Janusz but I know what the answer will be?? good luck .... Admin Don, are you talking about the kit boat or a boat built from plans? Please note that you CANNOT SCARF the hull panels supplied with the kit as they are designed to be put together with butt straps. The panels are simply not long enough to put scarf joins in. This feature of the kit makes the butt straps "a structural component of the hull." However, if you are not using a kit but are building from the plans instead, you will find that there is NO SPECIFICATION, NOTE OR DRAWING whatsoever stating the joining method for either the hull panels or the bunk longitudinals. The plans ALSO DO NOT SPECIFY what type of join should be used for all of the gunwales, chines and stringers. Although there is a longitudinal piece of 9mm ply down the middle of the deck, there is none noted athwartship for joining the deck panels either! The only reference in the blog about a butt join or a scarf join in the hull panels is here Trekka II Blog simply stating that a scarf is "more difficult" to do and that a butt join and straps are "easier." Even though Trekka II has butt straps THERE IS NO STATEMENT in the blog about butt joins being mandatory anywhere for plans builders (that I can currently see). Builders have rightly assumed for both the kit set and the plans built boats that a scarf join is THE preferred method for joining all of the solid longitudinal timber components, despite no plans specification to do so. Similarly, it is also Logical for plans builders to assume that a properly executed scarf join is THE PREFERRED METHOD of joining the over length plywood panels because there are NO INSTRUCTIONS TO DO OTHERWISE on the plans as supplied, the blog or the builders updates. I don't know if Gary.S is planning on using a kit or wants to build from plans like I will be doing, but it would be great to know if your directive is just for kit builders or also for plans builders as well. Cheers.
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Gary.S
New Member
HULL # 111
Posts: 23
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Screws
Feb 28, 2021 22:13:37 GMT
Post by Gary.S on Feb 28, 2021 22:13:37 GMT
Admin Don, are you talking about the kit boat or a boat built from plans? Please note that you CANNOT SCARF the hull panels supplied with the kit as they are designed to be put together with butt straps. The panels are simply not long enough to put scarf joins in. This feature of the kit makes the butt straps "a structural component of the hull." However, if you are not using a kit but are building from the plans instead, you will find that there is NO SPECIFICATION, NOTE OR DRAWING whatsoever stating the joining method for either the hull panels or the bunk longitudinals. The plans ALSO DO NOT SPECIFY what type of join should be used for all of the gunwales, chines and stringers. Although there is a longitudinal piece of 9mm ply down the middle of the deck, there is none noted athwartship for joining the deck panels either! The only reference in the blog about a butt join or a scarf join in the hull panels is here Trekka II Blog simply stating that a scarf is "more difficult" to do and that a butt join and straps are "easier." Even though Trekka II has butt straps THERE IS NO STATEMENT in the blog about butt joins being mandatory anywhere for plans builders (that I can currently see). Builders have rightly assumed for both the kit set and the plans built boats that a scarf join is THE preferred method for joining all of the solid longitudinal timber components, despite no plans specification to do so. Similarly, it is also Logical for plans builders to assume that a properly executed scarf join is THE PREFERRED METHOD of joining the over length plywood panels because there are NO INSTRUCTIONS TO DO OTHERWISE on the plans as supplied, the blog or the builders updates. I don't know if Gary.S is planning on using a kit or wants to build from plans like I will be doing, but it would be great to know if your directive is just for kit builders or also for plans builders as well. Cheers. I am building from plans so will be scarfing the panels. I think I will send an email to Jansz as I I have a few other questions for him. Regards Gary.S Boat # 111
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