LB26 Questions

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tedacrouse
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LB26 Questions

Post by tedacrouse » Sun Mar 03, 2019 4:56 pm

Hi Jacques, hope all is well.

I'm close to completion of the bottom of my LB26 but have the following questions (I hope numbering them will help in organizing a response):

1) There is no measurement noted in the plans for marking the rudder post to set the shaft axis (from the station) but I've extrapolated this to be 14.1". Is this correct?

2) What is the dimension of the "Swayback" of the Strut? I.e. at the bottom of the strut that attaches to the shaft how far back does this measure from the top of the strut mount that connects to the hull? I've contacted a manufacturer (exploring options who is asking) but if you have a parts store where I could order from this would be greatly appreciated as I think it would be much cheaper.

3) There is no reference in the Building Materials to a Shaft Log Part #. Could you kindly provide that now. As well is there a part number for the Shaft Log Seal as well? Just to note - I have located a Nanni Diesel exactly as in the specs so I will be moving forward with the Designed 1.5" shaft associated with the plans. Just to confirm if I don't locate the part # (and buy) and build my own Shaft Log I will need a 2" pvc pipe (to allow for the 1/4" glassing inside, resulting in a 1/4" clearance). Correct?

4) I went through all of the old posts and there were questions around the tabbing that I'm now curious about. In particular there's a requirement of an inside and outside lamination of DB120 at the chine. I'm taking this to be one - tabbing the outside of the hull (at the chine) prior to the regular lamination schedule and two - tabbing of the inside of the hull (at the chine) prior to the filling and lamination schedule. Is this correct?

Thank you for your continued support as I work through these next challenges.

Ted



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jacquesmm
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Re: LB26 Questions

Post by jacquesmm » Sun Mar 03, 2019 6:41 pm

If I don't reply, bump the post tomorrow. I am busy cooking now and I am at my 1st martini. I"ll reply in the AM.
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Fuzz
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Re: LB26 Questions

Post by Fuzz » Sun Mar 03, 2019 7:14 pm

Hello Ted,
Is there any chance you would start a build thread? I would love to see one of these going together :D
Fuzz

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Re: LB26 Questions

Post by fallguy1000 » Sun Mar 03, 2019 9:04 pm

I second that request for a picture or two. I did not answer any of these because not able, but a plan owner and love the boat.
My boat build is here -------->

viewtopic.php?f=12&t=62495

tedacrouse
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Re: LB26 Questions

Post by tedacrouse » Tue Mar 05, 2019 1:42 pm

Hi Jacques just 'bumping up' my LB 26 Questions...

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Re: LB26 Questions - BUMPED UP AGAIN

Post by tedacrouse » Wed Mar 13, 2019 7:43 am

Jacques I'm bumping up my questions again - are you able to respond?

Hi Jacques, hope all is well.

I'm close to completion of the bottom of my LB26 but have the following questions (I hope numbering them will help in organizing a response):

1) There is no measurement noted in the plans for marking the rudder post to set the shaft axis (from the station) but I've extrapolated this to be 14.1". Is this correct?

2) What is the dimension of the "Swayback" of the Strut? I.e. at the bottom of the strut that attaches to the shaft how far back does this measure from the top of the strut mount that connects to the hull? I've contacted a manufacturer (exploring options who is asking) but if you have a parts store where I could order from this would be greatly appreciated as I think it would be much cheaper.

3) There is no reference in the Building Materials to a Shaft Log Part # (as you actually reference in the plans). Could you kindly provide that now. As well is there a part number for the Shaft Log Seal as well? Just to note - I have located a Nanni Diesel exactly as in the specs so I will be moving forward with the Designed 1.5" shaft associated with the plans. Just to confirm if I don't locate the part # (and buy) and build my own Shaft Log I will need a 2" pvc pipe (to allow for the 1/4" glassing inside, resulting in a 1/4" clearance). Correct?

4) I went through all of the old posts and there were questions around the tabbing that I'm now curious about. In particular there's a requirement of an inside and outside lamination of DB120 at the chine. I'm taking this to be one - tabbing the outside of the hull (at the chine) prior to the regular lamination schedule and two - tabbing of the inside of the hull (at the chine) prior to the filling and lamination schedule. Is this correct?

Thank you for your continued support as I work through these next challenges.

Ted

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jacquesmm
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Re: LB26 Questions - BUMPED UP AGAIN

Post by jacquesmm » Wed Mar 13, 2019 10:14 am

tedacrouse wrote:
Wed Mar 13, 2019 7:43 am
Jacques I'm bumping up my questions again - are you able to respond?

Sorry, I did not see this question. Don't be afraid to bump a question after 24 hours.


1) There is no measurement noted in the plans for marking the rudder post to set the shaft axis (from the station) but I've extrapolated this to be 14.1". Is this correct?

2) What is the dimension of the "Swayback" of the Strut? I.e. at the bottom of the strut that attaches to the shaft how far back does this measure from the top of the strut mount that connects to the hull? I've contacted a manufacturer (exploring options who is asking) but if you have a parts store where I could order from this would be greatly appreciated as I think it would be much cheaper.
The dimension is on the drawing titled Machinery E283/6, to the left of the strut drawing, shaft line angle = 13.5 degrees. The swayback angle will vary with manufacturers, as long as there is some, it will be fine. The drawing shows 37 degrees.


3) There is no reference in the Building Materials to a Shaft Log Part # (as you actually reference in the plans). Could you kindly provide that now. As well is there a part number for the Shaft Log Seal as well? Just to note - I have located a Nanni Diesel exactly as in the specs so I will be moving forward with the Designed 1.5" shaft associated with the plans. Just to confirm if I don't locate the part # (and buy) and build my own Shaft Log I will need a 2" pvc pipe (to allow for the 1/4" glassing inside, resulting in a 1/4" clearance). Correct?
The shaft log is a simple pipe (PVC, fiberglass, metal, anything) that goes around the shaft, 1/4" clearance total is fine. There is no part number. I would make one with glass around a PVC pipe. What matters is that the inboard end is sturdy enough to take the hose clamps for the shaft seal. The shaft seal can be a plain stuffing box or a shaft seal like a Lasdrop. For a stuffing box, I would check with Wilcox-Crittenden, for a seal, I like Lasdrop but they are other good ones. There may be part numbers but they change over the years. Normally, we say that it is a stuffing box or shaft seal for a 1.5" shaft, that's all. I would buy all those parts from the same prop shop. That way they must match.
I show a Nanni diesel and I like them but many other engines can be used. Yanmar uses exactly the same block, same mounts locations if I remember well.


4) I went through all of the old posts and there were questions around the tabbing that I'm now curious about. In particular there's a requirement of an inside and outside lamination of DB120 at the chine. I'm taking this to be one - tabbing the outside of the hull (at the chine) prior to the regular lamination schedule and two - tabbing of the inside of the hull (at the chine) prior to the filling and lamination schedule. Is this correct?

The tabbing of the seams including the chine, is done independently of the wide fabric. In other words, you assemble the hull panels with tabbing (tape) at the seams, inside and outside and later, you will cover the whole hull with the wide fabric over the tabbing.
The wide fabric should go over all the seams: the bottom wide fabric overlaps the chine, the side panel wide fabric overlaps the chine etc.

About the machinery drawings: a couple years ago, we printed some of those drawings at the wrong scale while switching from Autocad to Rhino. The error was very clear, the parts sizes were multiplied or divided by 2 or 4. Don't give the drawings to a metal shop without checking that the dimensions make sense. You can check easily: the strut total height is about 13", the rudder blade about 18".
It was not a small error, you would see it right away: if your rudder blade is bigger than the boat, it's wrong!!!
Disregard the shaft end taper and coupling dimensions, the prop shop will know what to do. We put it there for builders who don;t have access to a prop shop.
Jacques Mertens - Designer
http://bateau.com

tedacrouse
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Re: LB26 Questions

Post by tedacrouse » Mon Apr 29, 2019 11:26 am

Thanks Jacques. I've been able to get back to this now.

Just a quick question re the rudder - looks like I can only get a 17" long blade or a 20" long blade. Was thinking more steerage but then thought about the draft implications. Would 17" be enough to control the Nanni (as I was able to secure the recommended Nanni for this boat).

Also would the prop shop be able to do a shaft log or is this just too specific to my keel size, etc that I should just be proceeding with the pvc (as I'm sure that'll be fine as long as I'm using a 2" pipe with a 1.5" shaft - will give about 0.25" clearance after glassing...).

Thanks,
Ted

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jacquesmm
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Re: LB26 Questions

Post by jacquesmm » Mon Apr 29, 2019 12:58 pm

Go for the 17", it's close enough. A large blade may vibrate at high speed and have too much drag.

The shaft log is a simple tube. A prop shop may sell them but it's very easy to make. Do a search on the web, I see lots of them.
Jacques Mertens - Designer
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tedacrouse
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Re: LB26 Questions

Post by tedacrouse » Mon Apr 29, 2019 1:27 pm

Thanks for the feedback Jacques I will indeed go ahead with the 17" as I believe that should be enough. Will do on the shaft log.

Thanks,
Ted

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