Theory - Drydocking and hull shape

CEShawn

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So I don't know if i am going crazy or not...

Typically on my RP35 they block my boat up with 4 boat stands, I'll probably ask for 6 next time.

So if I cut out the v-berth and deck forward of the main bulkhead...

Is anything going to change shape? Should I use more boat stands than normal? I have to imagine there are two stringers up there, but very curious if anyone has thought of this before or not or it doesnt apply.

Would I be better doing it in the water...
 

djmarchand

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If you are not careful, you will get some serious distortion.

The v-berth acts like a box beam and strengthens the hull forward. The deck is part of the hull structure and without it the hull sides could flex inward.

I would block it with 8 stands and then bolt some temporary 2x6s inside to take the place of the deck.

I assume that you are fixing a rotten deck core?

David
 

CEShawn

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Well, not sure what i am doing yet... but just playing in theory right now... wonder if I'd be better of doing this in the water then? That should keep the shape a little better? right now I only have half of a v-berth on one side.... I do get the temporary ones...

So it starts like this... I want to do a false bulkhead to cover up my electrical panels. But might as well make a counter top to it, but if I do that, I might as well correct how the bunks are connected, but if I do that, I might as well start by getting a look at the deck underneath as well as redoing the deck because of a soft spot...

None of which help with catching giants, lol...

Just trying to plan for the projects...
 

samhop

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6 stands block the keel good, if the cabin bulkhead is in no problem hacking out v berth and cabin floor. the molded top and the bulkhead will hold every thing together. you will find the 2 inbord stringers under the floor. watch the weight up foreword you might think about using Nida.
 

plowin

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I am not arguing with any of the above stated points but the blocking under the keel supports the weight of the boat, your stands just balance and keep the weight centered over the blocking. I would shoot a PM to one of our builders on the site and ask them what they think.
 

CEShawn

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Plowin I agree with you but for some reason the old ocean flexible flyers came to mind where they wanted more stands than normal. Just like I know some insurance company's years ago wanted certain boats to be put on railways only. That is a time gone by. I think I saw a 72 donzi or something close to it where when they replaced the interior wanted it set in place.
 

F/V First Team

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I wouldn't worry about additional stands, you should be fine. Chances are you have a pretty thick laminate for your hull. The top is going to keep the sheer defined and that holds the rest of the hull in tension - think of it like a Rubbermaid tote full of water with the lid on it. With the lid in place it stays in shape, when you pick the lid off of it there is a little bit of adjustment that it does on its own. Put the lid back on, and it's right back to original specs. So long as you don't take the top off and fill your boat full of water you should be fine :)
 

Frigate

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Shawn,

I know what the builder Plowin is PMing will say. Is do not let the yard put concrete blocks under the keel. Only wood blocking under the keel. Also you should have six stands under the boat. However with what you are talking about in projects think about two more sets of stands.
 

Toolate

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Took the whole cabin and floor back of the "house" off my 76 Luhrs flybridge and the door in the center of the rear bulkhead needed about 1/8" added to it when it all went back together. I think the roof settled about 3/16 and the sides of the boat spread the same amount when I took it all apart so looking at that I should have blocked the hull more solidly.

That boat was rotten/cored/planing hull without keel though so no real strength.

I would add an extra stand if you want to. Its free right? I think a boat has a bit of a different shape in the water than it does out. Nothing is 100% rigid.

I was surprised at the support for rigid mounting of engines in a recent thread based on my opinion (and it is just that- no expert here) that things move a bit when the boat is on the hard vs in the drink. Think there is a difference between newer boats and the old crappers I am used to.
 

CEShawn

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Thanks guys, that is why I am here:) ><">

First Team, as always your a benefit to this forum...
 
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