Building a Boat on Uneven ground

[David Deutsch]

Hi Everyone,

I have a unique problem in that I want to build a 28 foot boat in my back yard but I live on a hill. The back yard is 50 feet by 100 feet so it is quite huge.

The problem is that it slants down as hills are wont to do. There is no flat area that I can use yet.


I have several options but I am renting so I don't want to spend a lot of money renovating the place. I need help choosing the safest and best option. I welcome all advice!
Build a 30 x 15 foot deck out of wood. Time consuming and expensive.
Build 3 smaller decks to hold the boat up only.
Level an area 30 feet x 15 feet to make it flat ground. Down to the chalk.
Install 6 Brick squares (or something) to hold up the boat on either side. (My favorourite solution)
Notes:
I live in Brighton.
i have direct access to a driveway from where I intend to build the boat.
I have a £600 budget for this project.
I am pretty new to the forum and have been reading a lot of posts. I havn't found the answer to my question.

Thank you very much for help!

Dave

[Mike]

Hi David

Welcome to BBJW. Your problem is in fact quite common and far from 'unique'.

I will begin by asking you an important question or two, if you don't mind. You say you are renting. May I ask, then, if your tenancy agreement is an Assured Shorthold Tenancy and whether your landlord knows you are intending to build a 28 footer in 'his/her' backyard?

I ask because a 28' boat is going to take a fairly long time to build. If you have a long term tenancy and the build is fine by your landlord, then full steam ahead. Otherwise, you may run into trouble. This could come from the local council by way of complaints from neighbours (noise, nuisance, air pollution, and so on), from neighbours directly, or from your landlord. And you really don't want to try moving a partly built boat, at least until you have the hull completed.

As to the issue with levelling a build platform, I would suggest it depends to some extent on what boat you are building. If she's to be built on a jig, then don't worry about the ground being level. Just ensure the base platform of the jig is level. In other words, use uneven lengths for the support legs (I would suggest you set them into the ground using postcrete) so that the tops are all level fore and aft and side to side.

The advantage is also that the whole jig is easily removed once the build is finished and you need to restore the building area - to satisfy the landlord and comply with the terms of your tenancy.

Hope that is of some small help to you.

Best wishes

[David Deutsch]

Hi Mike,

Thank you VERY much for that!

To answer your questions:

1. I spoke to my landlord and neighbors already and everyone is fine with me doing this. I live in a semisecluded area so I am very confident i won't run in to trouble.

2. I have a 1 year renewable lease. I will be making improvements to the yard which is in a shambles so the owner is thrilled!

Now to your excellent advice. I do intend to build on a Jig. However, I want to know exactly what these "legs" look like. Are you talking about essentially planting a long 4X4 in to the ground like a fence post?

I take it that these legs then support the "Jig" straight up?

I havn't built a jig yet so i am trying to picture it.

One more question. Is there a maximum length and/or weight that this set up can support? I don't need an exact number of course, but I am till trying to figure out how big I can make this boat in my yard

"In other words, use uneven lengths for the support legs (I would suggest you set them into the ground using postcrete) so that the tops are all level fore and aft and side to side."

If I am understanding you right then you just MADE MY MONTH! I have been stressing over this point for 2 months! I have a garage and everything else I need but a flat surface!

Thanks!

Dave

[George Waite]

David
Are you intending to build the boat upside-down or right side up? The jig can be fabricated in steel tube (old scaffold tube) or in 4" x 4" timbers. Levelling options include a water level (clear plastic tubing), yardstick and bubble level, Piano wire and line bubble, optical dumpy level. If you lived a bit closer I would come and set it out for you. Mikes point re neighbours valid, are they ready for a few hours of sanding etc on a sunday afternoon?
George

[Mike]

Good news, then, Dave, but be careful. Neighbours can change their minds and turn on you. Come to that, a one year tenancy can begin well and then end up with the landlord giving you the flick. My advice would be to ensure you DON'T improve the rear garden until after you have built the boat.


I do intend to build on a Jig. However, I want to know exactly what these "legs" look like. Are you talking about essentially planting a long 4X4 in to the ground like a fence post?

Yup, exactly. The designer usually specifies the scantlings (timber sizes in this case) for the jig. However, 4 x4 legs ought to be fine, provided you have enough of them to support the weight of the jig plus the built boat, including motor if she's an inboard job. You don't want the whole lot sliding down the slope and into someone else's garden, do you? Dig a decently deep hole for each leg, then plant it upright like you would a fence post, add postcrete, then water. Make sure it doesn't move from vertical until the postcrete sets. Once set, you should have a good, solid, set of supports for the jig base, which must be true (in both axes).

If the designer hasn't described the required jig, I suggest you ask for his/her advice.


I take it that these legs then support the "Jig" straight up? I havn't built a jig yet so i am trying to picture it.

This suggests you don't yet have the jig specs, so see above answer. I haven't yet seen a set of boat plans that don't include some specs for the jig. How about telling us what boat you have in mind?


If I am understanding you right then you just MADE MY MONTH! I have been stressing over this point for 2 months! I have a garage and everything else I need but a flat surface!

The ONLY flat surface you will really need to get you started is the jig base. Make sure you get that right and all else becomes that much easier. Just wait 'til you start building the boat. Very little on a boat is flat or straight! ;)

Go for it, Dave, but don't hang about. One year is very short and a 28 footer will usually take much longer than that unless you are a professional boatbuilder.

Best of luck. Keep us all posted, eh?

[Mike]

David
Are you intending to build the boat upside-down or right side up? The jig can be fabricated in steel tube (old scaffold tube) or in 4" x 4" timbers. Levelling options include a water level (clear plastic tubing), yardstick and bubble level, Piano wire and line bubble, optical dumpy level. If you lived a bit closer I would come and set it out for you. Mikes point re neighbours valid, are they ready for a few hours of sanding etc on a sunday afternoon?
GeorgeDave

George knows what he's talking about, I can assure you. Perhaps you should send him a return train ticket - first class would be entirely appropriate! Ha ha. :rofl:

[George Waite]

Mike
Thank you for the recommendation.
David
Have posted a photo of a typical simple jig for a flat bottomed craft on Photo gallery section of the website under "St Pierre Dory (http://backyardboatbuilding.org.uk/forums/album.php?albumid=24&pictureid=771)".

[Edit addition: I've put a direct link to the photo into your post, George. Are those steel legs concreted into place, btw, or do they have a steel plate on the bottom of each leg? Regards, Mike]

[George Waite]

Mike/David
The legs on my jig are set in dense gravel to a depth of about 600mm to an existing concrete slab. However the base type will depend on the soil/substrate, David seems to think that the substrate is chalk and given the Geology of the South Downs/Brighton area he is probably right. If he has a Civil Engineer or Land Surveyor in his circle of friends then it would be a simple matter for them to set out a level area for him even if it costs him a few pints!

[jwboatdesigns]

I'd dig, sweat is cheap and there is plenty of better things you can spend your money on. A couple of days with a shovel and wheelbarrow will kill the job, provide you with firm stable footing and you can enlarge it easily if you need to.
Note, sharpen the shovel, it makes the job much easier, funny how seldom people do that,

John W


Hi Everyone,

I have a unique problem in that I want to build a 28 foot boat in my back yard but I live on a hill. The back yard is 50 feet by 100 feet so it is quite huge.

The problem is that it slants down as hills are wont to do. There is no flat area that I can use yet.



I have several options but I am renting so I don't want to spend a lot of money renovating the place. I need help choosing the safest and best option. I welcome all advice!
Build a 30 x 15 foot deck out of wood. Time consuming and expensive.
Build 3 smaller decks to hold the boat up only.
Level an area 30 feet x 15 feet to make it flat ground. Down to the chalk.
Install 6 Brick squares (or something) to hold up the boat on either side. (My favorourite solution)
Notes:
I live in Brighton.
i have direct access to a driveway from where I intend to build the boat.
I have a £600 budget for this project.
I am pretty new to the forum and have been reading a lot of posts. I havn't found the answer to my question.

Thank you very much for help!

Dave

[David Deutsch]

Wow, you guys are just amazing!

Thank you all so much for this. I can't tell you how much easier things just got!

George, do you do this professionally? If i can't figure out on my own i would pay you to help me out!

Thanks guys!

I will keep you all posted as I go.

Dave

[George Waite]

David
I am a retired Engineer so setting/checking levels was part of my job at one time. The reason that I advocate someone finding or setting out some levels for you is that it can save you a lot of unnecessary work. The technique is to quite simply find the existing low point with an optical level and excavate down to that level (using a spade and wheelbarrow) before you do anything else. If you have a friend who is a mason or bricklayer then they can help with this. When you have a large enough area then you can build your jig. The tool for this can consist of a simple plastic tube water level bought from "Toolstation" for £17. you do not need £2000 worth of kit in fact Traditional shipyards (such as the one that I trained in) have always used water levels for transverse hull checks when the vessel is on the slipway. For longitudinal checks on the jig I would use a length of stretched steel wire or a masons stringline (pulled tight) with a small (pocket size) clip-on sliding bubble level incorporated at mid span. Again, If you have a mason or bricklayer in your circle of friends then the level and stringline can be borrowed. If not then purchased from hire shop or good builders merchant. Oh and remember to monitor the levels during costruction as the increasing weight can cause the jig to sink causing some real head scratching moments. If you need any extra help when you actually intend to start, I do not ask payment but some petrol money for my bike might be handy as the Gubbermint aren't exactly generous with pensions (when they get around to paying me!).

[Mike]

Dave

It looks like that one is sorted out, mate. I do recommend George if you need any help. He is a man of relatively few words but every one of 'em is right on the button. He rides a beauty of a motorbike too.

Warn the neighbours that he's coming, though, or they'll think you are in trouble with the fuzz - or a group of Hells's Angels! He heh :rofl:

Top man is our George. Spins a good yarn too as can be seen on this forum from time to time. He is worth much more than 'petrol money', take it from me.

[jwboatdesigns]

Can I suggest, in light of your being on a rented property and likely to have to reinstate the building site to something less like a shipyard, that you go down to your local builders merchant or DIY hardware shop and look in the big bins of galvanised ( hot zinc coated ) steel bits and pieces. The ones you want are know where I live as " ragbolts". Big hefty bolts with split and splayed ends that are set into wet concrete and which can, once the concrete is set, be used to bolt angle brackets or baulks of wood to the concrete pads.
This will mean that you can just unbolt the building jig when the time comes rather than having to deal with upright set into cement.

JohnW

[Mike]

It's not often I find myself disagreeing with JW but I see little difference twixt using 'ragbolts' and using a wooden 'four by' in that both can be easily sawn, or ground, off at ground level and made to disappear beneath a layer of soil.

I speak with some considerable forethought in that I used our equivalent of 'ragbolts' to sit the uprights of my shelter on to the concrete pad.

Dave, you can take a look at my blog on preparing for a build right here. This link (http://www.backyardboatbuilding.org.uk/forums/blog.php?b=39) takes you to the relevant photos page.

Note that the blog title is rather outdated, in that our intentions then were different. I've since had to modify the plans, more than once. But the way the shelter was built is as follows.

The very first thing I did was to buy the 'ragbolts' (well, they are actually just metal plates that take a four by four fence post). I set the positions out for the uprights (4 x 2s in my case) and dug holes in the ground. I then used postcrete to secure each 'ragbolt' into position above each hole. They are thus set into a deep, concrete, foot. I then erected the shelter on those feet. The concrete pad you see in the photos in fact came last as the entire shelter was built on the soil and sub-soil (clay in my case).

It has been a fantastic shelter in that its suffered some extremes of weather from deep snow to hot, sunny, days; from still calm winds to gale force blows, and has never let me down. Of course, I could have just slung a tarpaulin over the roof but preferred to use clear plastic corrugated sheets instead. Personal preference, that one.

So, if you think about it laterally, you can do exactly the same, even on a fairly steep slope. As others have said here, it may depend to a degree upon the substrate but a deep enough hole filled with concrete ought to do the job in providing a strong and stable platform upon which to build your jig. No need for brickwork or terracing using timber. Just a framework of supports with a nice level jig on the top. Simplez!

[David Deutsch]

Thank you all so much for your advice. I am confident now that I can build a jig with posts like discussed.

Now i have a slew of other things to figure out and get my head around!

This is definately the best forum ever for Boat building!

Thanks again guys.

DAve

[Mike]

You're most welcome, Dave. Don't forget to posts a few pics when you get going. We're always keen to see how others are building their boats.

It's what this site is all about really. I hope we've truly been of some help to you. :approval:

Best wishes