Sands / Props for on the hard

[SorinCT]

I am doing some research in order to plan building a DIY boat stand for my Bavaria 36 2002. There are basically 2 types of designs commonly used, the individual props, chained together in pairs and kept under some tension (boat resting on the keel fin) and a stand which also incorporates fixed props. At the moment I am leaning towards designing a fixed rectangular  stand with detachable feet, all parts being fastened together using nuts and bolts. I want to keep it easy to transport using a pick-up truck or small van.
Most likely i will need to eyeball a lot of dimensions and either make it extremely adjustable or go by luck as boat is in the water and will stay so for 1-3 years more.

Does anybody have any experience in design or have you run in some difficulties while using props/stands?

Some photos for reference as to expected design.

[symphony2]

If it is just for your use for just one boat then the fixed leg cradle in your first photo is the easiest and cheapest type. However they are difficult to store when not in use. Some yards here use those and stack them in the summer. However the adjustable ones are more common because they can be used for a variety of boats and can be dismantled for stowage. There are 2 types, the first with a fixed base and removable arms, the second ones that can be completely dismantled for transport in a large car or van. The second is popular in out club because there is nowhere to store cradles. Usually members share ownership of one cradle as we usually only have boats out of the water for 3 or 4 weeks at a time.

You might get some ideas here
yachtlegs.co.uk/index.pl

[SorinCT]

It will be used for my boat only but may be lend out to 2 of my marina neighbors (same Bav36). I want to avoid making a fully fixed frame and legs as transport and stowage will get difficult. My plan is to break it in manageable parts and store it at my house or workshop.

Thank-you very much for the link, there are some good designs there. Only thing is to guesstimate the dimensions required for the boat and whip up a 3d model.

[sy_Anniina]

I use an XL6 cradle from https://x-cradle.com/index.php?id_category=10&controller=category&id_lang=1

Hope You get.some ideas from there. The diagonal supports are like huge coarse turnbuckles.

BR

Tommi
s/y Anniina

[Yngmar]

Most yards use cradles because they fit almost any boat, are easy to stack when not used and moved around easily (empty) with a forklift. Some have cradle movers that can haul a boat around while resting in one of their cradlesm, allowing them to pack the boats tighter than is possible with travelift.

If you have a place for your own stand all year around, you don't need an adjustable cradle that fits any boat, only yours. This is easier and cheaper to build and lets you even do useful stuff such as having the keel hang in the air rather than rest on the ground, which deforms the hull less and lets you access the bottom of the keel for antifouling, which is normally not so easy.

Raceboats often have such custom stands and even truck them around when the boat is relocated. They are shaped to fit the hull exactly and must rest in exact locations (where the bulkheads are). Example (the slot is for the keel to pass through):



This one has the additional bonus of folding down when not in use, but that's up to you.

[tiger79]

It will be used for my boat only but may be lend out to 2 of my marina neighbors (same Bav36).

I think you need a system with at least 6 supports for the hull.  The support legs really need to be triangulated for security, as well as being adjustable.  I'm not sure that a DIY cradle which is strong enough would be easily transportable.  A quick look around any marina will show you that the cradles used by boatyards are incredibly sturdy, for good reasons - the loads on the cradle when the wind blows can be huge.  Also, if you're thinking of lending it to others, you'll need to come up with a formal agreement removing your responsibility for any mishaps.

My boat is 37ft, here's a pic of the cradle my marina uses for it.  I wouldn't want anything less sturdy.

[SorinCT]

Local marina does not have any crane, means of transport or cradles. If you are lucky you can get a space for the full winter on the hard but usually you are limited to pulling it out 2-3 weeks for repair jobs and new paint and back in the water it goes.
Indeed i do not want to consider something flimsy but it needs to be transportable by truck/van. My older boat (see pic) has a DIY heavy duty cradle which is transported together with the boat. When i had to shift it from storage to near the water for haul out, it barely fit in the back of a tow-truck platform (with crane). Although having it built like for supertankers, it's overkill and gives a lot of headaches.

Regarding the boat's point of support, I'm not sure which is best at the moment, standing on keel or lateral supports. Both have advantages and disadvantages but seeing that most likely it will stay on the hard maximum 1-2 months at a time, resting on the keel might not be so terrible.

[Yngmar]

Standing on the keel is the norm for most boats in most yards, and it's okay - the boats are designed to cope, it's just not fantastic, you will see some hull deflection if you look. The custom cradle I showed above where the boat sits on shaped hull supports is a luxury with advantages, but not the norm. But since you're planning to make one for a specific boat, why not - it's easier to build and as you can see, easy to fold flat for transport (sans boat).

There must always be lateral supports while the boat is standing on the keel, but they just keep the boat from tipping over, they do not carry the weight of the hull (unlike the custom cradle I showed above). They can still see significant loads in high winds, so can't be too flimsy, and most yards have ceased the use of single (unconnected) stands due to the occasional boat falling over. Although in one Tunisian yard they still used barrels and logs and whatever scrap they had laying around when our friends hauled there

[SorinCT]

To be honest it does not look so simple to make because you need to account for the hull shape at different points (bulkheads) where structural stiffness is best. With a line plan drawing, CAD or even the boat out of the water, all measurements can be taken but not in current conditions.

As cost for e pre-built cradle, can reach from 1500 to 3000 EUR + international shipping which is a joke. Materials and supplies at current prices look around 6-700 EUR.

[symphony2]

If you are making a dedicated cradle with U shaped supports as Yngmar suggests then it is not difficult to locate them. The forward one goes under the main bulkhead just forward of the mast and the aft one under the aft cabin bulkhead under the engine. It is quite common to mould a support around the hull at those points about 60cm wide which become part of the cradle. The keel should be located to prevent sideways movement, but the supports take most of the weight.

With the type that uses adjustable supports, the weight is taken mostly by the keel and the supports are mainly there to keep the boat upright and because they take little weight the positioning in relation to the bulkheads is less critical. My boat goes in a 6 point cradle like the one in tiger 79 post.

[sy_Anniina]

In case you end up making adjustable & dismountable "keel standing" type cradle, here are some detail photos from my cradle, in case you want to duplicate some solutions.

This cradle is quite easily bolted together from relatively small pieces, I would imagine a pick-up / van is enough to transport it.

BR

Tommi
s/y Anniina

[SorinCT]

Great photos, thank-you for the help. I intend to make something similar, although little bit more beefy.

[Bav32]

Great photos, thank-you for the help. I intend to make something similar, although little bit more beefy.

No need to beef-up that cradle. It should hold a 40+ ft boat with no worries. The boat stands on the keel and the stands are just there to keep the boat in balance. All that said, Bavarias are really heavy in the aft. If you build a cradle with four stands, then I would suggest to get one loose stand to put under the rear part of the boat