Stepping the mast with a plum bob...two questions.

[HardeeHarHar]

Anyone who has read my blogs knows that I tend to worry about the "correct" procedure that should be used in building a model ship.  One of the things I have been worrying about lately was how to step the masts on my Granado in a way where I could guarantee they would be aligned relatively straight (albeit with the required rake), and whether I should use  wood glue (PVA) or the time control CA I have been using a lot of lately.  In the process of worrying over this and other things, I ran across one post where an individual had a laser line system and used that to make sure his mast was glued in place with the correct orientation.   That seemed like a high tech solution, but I don't (yet) have a laser level system....so I just kept worrying, thinking about having my wife help me eyeball it, etc.  (I know, I need mental help).  But it finally occurred to me that a simple *plum bob* might just be the most cost effective solution.  So my questions are: 1) how many individuals have actually used a plum bob to step their masts, or what other techniques might be suggested for me to consider/worry over to get the mast stepped the first time; 2) what glue do you recommend for this endeavor.  PLEASE HELP ME STOP WORRYING ABOUT THIS (so I can worry about something else =).

Best regards, and happy holidays,

Brian

[John Ruy]

Hi Brian,

 

Often had that worry myself, eyeballing it just isn’t good enough as I improve my  skills. I like the plumb bob idea 💡 sounds like it should work. I’m working my Bluenose Main Shrouds right now and I’ll give it a go. 
 

As for gluing in the masts, it was recommended to me (bluejacket instructions) to not glue in your masts and let the standing rigging do its job to hold everything in proper alignment. This way down the line when your historic model needs restoration the masts can be removed. That said the mast alignment is left up to your tensioning of the shrouds and standing rigging. This is where I think your plumb bob idea will come into play, you should be able to calculate the required rake as well. Just hang the plumb bob from the aft of the trestle tree and use your best geometry. Of course we will have to be sure the deck is leveled up. 
 

cheers 🍻 

John
 

 

[HardeeHarHar]

44 minutes ago, John Ruy said:

it was recommended to me (bluejacket instructions) to not glue in your masts and let the standing rigging do its job to hold everything in proper alignment.

Thanks for the response John, I greatly appreciate it.  Now I can worry about rigging a ship with wobbly masts!!!!

[AJohnson]

Hi Brian, ashamed to admit I just use pva glue and eyeball it! 👀

That said I think the Mk.1 eyeball is pretty good, we can all spot a wonky picture frame 🖼️  🤣

[Bob Cleek]

A plumb bob would be a huge PIA to try to use for this purpose. It will get in the way and you'll probably knock it around trying to measure the angle off of vertical while it's hanging there. 

 

John is 100% right that, for several good reasons, you don't want to glue your mast rigidly in place. It is best to use your rigging to adjust the angle of the masts as is done in real life. How this is done depends upon the construction of your model. If your hull is a solid block, you're going to have to drill a hole, a bit larger than the heel of your mast and (hopefully) at the angle necessary. If your hull is hollow, you'll have to deal with however that hull is designed to hold the mast. For your purposes, you want a loose fit. 

 

To set up your mast, you must have your hull positioned dead level on its waterline in all directions. Note that some lines are drawn with the bottom of the keel parallel to the baseline and others not. You need to measure the rake of the mast on the plan using a level waterline as your point of reference. With your hull perfectly level on its waterline, build yourself a card stock jig against which you can compare your mast's positioning. Think "carpenter's or machinist's square with a fixed angle matching your mast rake, or a fancy "double ended" one with one side of the "arm" at a right angle and the other side cut to the angle of your mast rake. (Get out your Martha Stewart hot melt glue gun for this job. ) Select a convenient flat physical reference point on your hull. Usually, there will be a space from rail to rail where a flat base for such a jig can be laid. If you are using a building board and can mount your hull on an even keel with its waterline parallel to the building board, you can also build a reference jig which stands on the level building board, possibly straddling your hull. In this fashion, you can compare your angles "from the top down rather than the bottom up.") To build a cardstock jig, just erect from a flat reference base a perfectly perpendicular "fin" running fore and aft relative to your hull to form a "T" section. Use bracing triangles at the joints if you have to make it rigid, but you want this "fin" to stand perfectly plumb on your perfectly flat base that is perfectly parallel to the hull's waterline. The forward edge of this "fin" should be cut to the same angle as the mast as shown on the plans.  The aft edge of this "fin" should be perfectly perpendicular to the base. The perpendicular edge will serve as your reference right angle for the mast's fore and aft perpendicularity and its angled edge will serve as your reference for your mast's rake.

 

When you duplicate the mast rake angle from the plans, be sure to measure it from the center of the mast! Because the mast will usually be tapered, if you measure your rake angle from the outside edge of the mast section drawing, it will be wrong because of the error created by the additional taper angle of the mast. When you use this jig to set the angle of your mast, again take notice of matching the angle of your jig to the center of your mast. I suppose you could just measure the rake angle on the plans from the edge of the section drawing of the mast and then just compare that angle of the side of the tapered mast to your tapered mast and get the same result, except that the opportunity for error seems greater in the latter approach.  

 

There are a few ways to adjust your mast using your jig.

 

The most obvious is to adjust your mast by using your standing rigging as it is done in real life. One uses the stays to adjust for rake and the shrouds to adjust for perpendicularity port and starboard. This is primarily done by taking up on the deadeyes and headstay and backstay lashings. This process will be necessary in any event if your rigging is to be properly taut and not hanging slack, but it's often difficult to accomplish in practice without the mast being fairly rigidly oriented as you would wish to begin with. For that reason, I advise leaving your rigging slack and using one of the following methods to orient the mast somewhat rigidly first, and then take up the slack in your rigging. 

 

One way to secure your mast independent of the rigging is to adjust the angle of the mast at the mast step and mast partners at the deck by using the mast step as the fulcrum and placing wedges or shims between the partners (or hole in your deck or solid hull... whatever)) to adjust the orientation of the mast. 

 

Another less tedious way to do this is to use a malleable material such as soft wax or modeling clay packed between the side of the mast and the mast partners. This will allow you to position your mast by moving it, with the malleable material repositioning itself to accommodate the mast's movement, while still holding it in position after it's moved. I would not advise using a "malleable material" which will harden over time if it is going to make it difficult to remove the mast if that is ever necessary for servicing or repairs.  I suggest that the non-hardening "malleable material" be supplemented or replaced by wedges or shims to ensure greater rigidity once the mast is properly oriented. After the mast is properly oriented, the slack in the standing rigging can be taken up. Be careful not to overdo the tightening, though. You don't want to pull the mast out of its proper position. 

 

Don't forget as well that sometimes the mast rake isn't the same in each of a vessel's masts. Check the rake of each mast independently to be sure. It may be off only slightly, but it may make a significant difference in the appearance of the model. Also remember that the longer the mast, the greater the distance of movement at the far end when adjusting it. Keep in mind that it only takes a very small bit of movement at the partners of a mainmast to move its topmast truck a noticeable amount. If you are only setting up a "baldheaded" mainmast, it can look fine, but be noticeably out of whack later after you've rigged all the tophamper! 

 

You can come very close but understand that you'll probably never get it perfect. Few, if any full-scale ships can say their masts are perfectly oriented and sailing ships are meant to pitch and heel in a sea, anyway, so who's going to know the difference? The inexact positioning of a mast is but one of the factors which virtually guarantees that every sailing vessel will always be faster to windward on one tack than on the other.  

. 

Edited December 15, 2023 by Bob Cleek

[John Ruy]

50 minutes ago, HardeeHarHar said:

Thanks for the response John, I greatly appreciate it.  Now I can worry about rigging a ship with wobbly masts!!!!

I hear ya…. Your Plumb Bob idea works great. 
If you look closely the Fore Mast is not Plumb. Using this method I did tighten up the port side shrouds and brought the mast up straighter. Slight adjustment over the eye ball 👁️. 

Rake can be measured as well. 🤪

 

Depends how much you want to “worry” about it and will it change as the model ages (probably). LOL 😆 

 

 

[allanyed]

3 hours ago, HardeeHarHar said:

plum bob to step their masts

I too like that idea as long as the waterline of the model is sitting perfectly horizontal.

Allan

[dvm27]

At the risk of sounding hieratical I would suggest not gluing the mast to the step. If, for some reason the ship is ever rerigged or part of the mast breaks, being able to remove it makes this very easy. As an example look at Olha's conservation of the HMS Boreas (YouTube). Assuming the foot of the mast is fitted loosely into some sort of step the standing rigging will keep the masts perfectly positioned once the laniards are reeved and tensioned. An additional advantage is that some adjustments are still possible in the mast position if warpage occurs in the months it takes to complete the rigging process. 

[Jim Lad]

Have to agree with Greg. Not gluing the foot of the mast to the step is a great investment in future refurbishments or repairs!

 

John

[Seahawk1313]

Hi Brian.  I don't glue any of the masts.  I run temporary lines to steady the masts until the rigging is set up.  I use card templates to check the angles, but I think eyeballing works fine. -Hal

[druxey]

While rigging, you can fine-tune the rake (if any) and plumb of the masts.

[wmherbert]

I first use an adjustable square . I place it on the plans to get the proper rake. Then I place the model on a flat level surface and adjust so boat is level side to side and waterline is level. Then I place the adjustable level along side the model and sight its edge and line up the mast fore and aft.

Then a big carpenter's square (18×24 inches) I place directly in front on the boat and sight back along its edge to line up the mast. I have a jig that I made to steady the mast and hold it in position. I can slide the boat fore and aft and side to side to move the mast until everything lines up. 

Doesn't take that long and I think it gets it as good as is possible.

Bill

[wmherbert]

I do glue the masts with PVA while doing the adjusting . And then when glue is dry I  tie down temporary shrouds down to the sides of the model to steady them until actual shrouds are installed.

Bill

[Dr PR]

DO NOT GLUE THE MASTS IN PLACE! After the shrouds and stays are added the masts cannot go anywhere.

 

Careful about using the "waterline level" idea. This assumes the waterline is actually in the correct position. If for some reason it is a bit lower on one side than the other,and you "level" the waterline, then your mast will not be perpendicular to the deck (from side to side) and this will be VERY obvious when you look at the model.

 

You want to get the deck level - as John Ruy shows in his photos. If the model has bulwarks, and IF your bulwark cap rails are the same height above the deck on either side of the mast, you can use the tops of the rails as a reference and level them.

 

I place something across the bulwarks and behind the mast as my horizontal reference. Then I use an ordinary right angle drafting square placed on the horizontal piece to align the mast. This method does not require the hull to be "level" in any orientation. The mast is positioned relative to the hull, and not relative to the Earth.

 

The plum bob will work IFF your deck is horizontal relative to the Earth - hence the spirit level in John's photo.

 

****

 

It is a bit late to be thinking about stepping the masts when you get to the point you want to start rigging. That should have been done while the hull and deck were being constructed. I show a technique in this post for setting the fore-aft rake and positioning the mast vertical port-starboard.

 

https://modelshipworld.com/topic/19611-albatros-by-dr-pr-mantua-scale-148-revenue-cutter-kitbash-about-1815/?do=findComment&comment=599087

 

I am just getting to the point I want to step the masts and start rigging. When I temporarily install the masts they are still perfectly vertical and have the desired rake.

 

However, experience tells me that I can bend the masts from side to side while installing the shrouds and stays. So I will have to be careful and used the actual procedure for installing them, starting on the starboard side for one line/set, then on the port side for the next, back to starboard for the third, etc. The first few stays and shrouds are important. After you get them rigged without bending the mast they will stiffen the structure and resist further bending.

 

BUT IF YOU SET THE SHROUDS/STAYS TO BEND THE MAST YOU WILL HAVE TO REMOVE THEM ALL AND START OVER.

 

Edited December 16, 2023 by Dr PR

[popeye2sea]

I believe that the order of setting up the rigging is important as well.

Start by establishing the rake of the mast with the fore stay. Once the mast is properly stayed move on to the shrouds.

Here is where some may disagree with my method.  Since the rearmost shrouds have the greatest angle and therefore the greatest influence on the position of the mast I start there.  If you go from forward to aft then a slight over tensioning of the after shrouds will lead to a bit of slack in the shrouds further forward.

 

Regards,

Henry

[bartley]

I agree with those who say not to glue the mast at all.  However, in most cases there is quite a deep slot cut into the bulkhead under the mast which should set the rake quite at least approximately,.  As you tighten up the rigging you still need to check th alignment I used to use a plumb bob but always found this a real PIA as it starts to swing on the slightest movement.  I now use a laser level (quite a cheap one). I set it up about 1 m from the ship and it does NOT move and it projects a cross so that you can adjust the deck to match the horizontal line and the mast to match the vertical line.  For the rake you can use a jig to tilt the ship forward by the correct amount and use the laser level again.

 

John

[BANYAN]

Hi all, the method I use is based on the 'square' idea but utilises a jig. 

 

 I make the jig as a triangle with a flat base that sits on the deck.  I then cut the leading edge to the correct angle have set that up with a protractor; the angle  (or straightness of the trailing edge does not matter.  I glue/tack a small slat on either side of the leading edge forming a channel within which the mast sits - but I also do not glue the mast in.  This cradle of sorts holds the mast in the correct alignment while I place the major standing rigging that stabilises the mast.

 

The jig is as thick, or slightly thicker, as the mast itself.  I usually make this from scrap wood (preferable something stable such as MDF)  but it  does not have to be very large; typically, a base of 2-3", and about 4-6" high I find is more than enough, and it remains small enough to extract it though the gaps in the rigging - note that I have usually fitted the upper masts off the model before this.   I tack-glue a bit of scrap material (usually plastic) to the base that has been shaped to conform with the side of the inside of the bulwarks, or other fittings keep the whole assembly centred on the centre-line and aligned correctly.  This done of thin material and tacked only so that it can easily be removed/separated from the jig for its removal.   I hope this all makes sense?

 

I then level the model in my building base (if not done earlier) by placing small bubble levels on the deck and adjust as required.  Once level, I secure the hull in the building base.    This method allows me to have the mast at the correct rake and also minimizing the chances of it being moved too far to port or stbd.  

 

Just an idea for an alternate solution.

[jgsandberg]

I agree with not using any glue when stepping masts. My solution is to install a sharp pin in the center of the base of the mast, and after making all final adjustments, simply press the mast down into place. It remains firmly in place, yet removable, with the added benefit of being able to tighten the rigging somewhat further on by simply adjusting the mast upward.

[Wawona59]

I think the plumb bob is a simple way to go.  It would work on the same principle as a navigational quadrant.  

The rake of the mast would be determined by the distance from the base of the mast aft along the centerline of the deck.  The mast is vertical when the plumb bob lines up with the centerline of the deck at the desired rake angle.  Another option would be to make small wooden blocks from some scrap at the desired rake angle.  Then use the angle of the blocks to set the rake angle of the mast.  The wooden block method is very similar to Banyan's method.