GV10 Stop and Start Project

[fallguy1000]

Of course mouseholes are not possible at the transom and a few other locations.

Mouseholes prevent stress cracks, btw. Those occur from having a massive weld in the corner and that weld can damage surrounding structures.

My expertise is limited to other reading, but your frames woth the angles look like they did not have the needed relief.

Wish I knew more and sorry if I missed or you knew.

[MikeyGnz]

Very cool! I was totally joking about the repairman.

I guessed so but if patience is a virtue I'm not very virtuous.

Good luck. Love the work and watching the welds improve. Do you know what a mousehole is?

When you weld a boat, no weld is allowed at intersections of three planes. Instead a relief hole is cut on the transverse framing. Aka mousehole.

Thanks for the info Fallguy

I didn't know about mouseholes but from a quick look on google there seems to be a bit of controversy about them. A set of boat construction course lecture notes I found refers to this https://www.steelconstruction.info/Stif ... Cope_holes. Based on those notes the coping hole or mouse hole is an easy way of getting clearance for one weld bead to pass completely through the intersection without having to precisely measure the weld bead and shape the third plate precisely. That site is for steel and not alloy where the stress crack issue is larger though.

I'll look through my book https://www.bookdepository.com/Boatbuil ... 0071443180 tonight when I get home.

I am going to be trying to turn the frames into watertight compartments so want to avoid mouseholes. If cracking becomes an issue I can add them later when doing repairs.

[MikeyGnz]

His (welder repair man) first day back was a Saturday and they only work a half day on Saturdays. I decided to give him that to catch up and will be calling when they open today.

Gave a call to the repair place and turns out today is his first day back so no update on the repair yet. Good that I called though because it had been left in the wrong bay and the repairer didn't know anything about it.

[fallguy1000]

To build watertght with the mousehole; you'd use foam I'd say.

Here is good reading on trouble welding in these corners..

https://www.boatdesign.net/threads/crac ... ost-843890


Kind regards. I am eyeing the design for a tender.

[MikeyGnz]

To build watertght with the mousehole; you'd use foam I'd say.

Here is good reading on trouble welding in these corners..

https://www.boatdesign.net/threads/crac ... ost-843890


Kind regards. I am eyeing the design for a tender.

Thanks for the information FallGuy.

I have done a count and there are 31 or 39 (depends on the number of stringers) places where I have welds with 3 or more panels/frames joining. Of these 6 are unavoidable as they join hull panels to the transom or bow along the chine or keel. Of the remaining joins there will be cope holes at all but 13 where I want to maintain water tightness. 3 of these are within 150mm/6” of the bow so I do not expect high stress as they will only be in the water at low speeds.

Given that this particular boat is smallish at 3m/10ft with 2.5mm thick panels and 3mm thick frames I think it fits into the category of over-engineered. I will be the only person using the outboard with the boat under oar power most of the time so I am tempted to risk it with the remaining 10 joints. They are in visible locations and I can check for cracks after each use and repair as required.



In other news my welder is being repaired and should be ready for this weekend.

[fallguy1000]

The only added benefit of the cope is a smidge less weight and ease of welding.

[MikeyGnz]

Just been told welder is repaired and I can pick it up in the morning. Tomorrow the build recomences.

[OrangeQuest]

Just been told welder is repaired and I can pick it up in the morning. Tomorrow the build recomences.

Good luck!

[MikeyGnz]

Got some more welding done today then welder died again, back to repairman tomorrow.

Since I didn't finish over Christmas and the project is stop/start I've changed the title of my thread.

[fallguy1000]

Don't give up!

Have you calculated a final weight?0