Mechanical design engineer here - I ran an FEA simulation of your M10 bolt constrained as close as possible to what you show on screen. If you used 304SS bolts, they will yield at about 300LBF each. If the 441LB load is truly evenly distributed across the 8 bolts, you have a safety factor of about 5.4 which is excellent.

Carb rebuild deserves an instant thumbs up!

honestly, you can lift that entire boat with them bolts. god only knows i've lifted enough engines with them.

I don't think the decks look ugly Mark!...I think they "match" the authentic/rustic look of Mahi!...You're making such great progress, so darn proud & love the way you don't edit things like you falling in-between the planks!!! You're just like Mahi - Authentic!!!! Keep going Sparks - You've got this👏👍💪👌 ⛵️Love Mum ⛵️🌟

Instead of sanding the deck you should try pressure washing it first. Way less effort and it’ll make the boards all look new.

Ref carb fault... Next time mix a bit of " mechanic in a bottle" in your fuel and it will dissolve the crud 👍🙂

Bigger bolt = bigger hole = less strenght on the stainless tubing. M10 is enough :)

Get your self a small captsian mount it mid deck and use this to lift both motors up at same time

.... and in the next episode of the kamakazi craftsman .... 😜 I'd say it's not the strength of the bolt itself, but the strength of the point of contact with the box section. a tubular sleeve welded into the box section would increase the overall strength of the system massively. (Remember vibration of the engine will distort the unsleeved holes over time)

There are aftermarket hydrofoils made for outboards that can help it plane.

If you're going to leave the outboards sitting for a long period of time you should disconnect the fuel and run the engine until it runs out of fuel, that way it won't sit in the bowl and gum up.

Could I suggest that the next time your shopping for bolts/nuts ect, please consider buying a few acorn nuts to top off your threaded bar. They will wind down on top of your nylon nuts you've put on and cover the rough cut thread. It will save you at some point from slicing your flesh. Top channel dude. Cheers

Really pleased that you have put spacer sleeves inside the box sections.

Mark when you drill remember to wear safety glasses please. We love your videos.☀️

I’m sure it will be great to have more sturdy useable space on board! You’ve done a lot of work to get to this point!

I would like end caps on all those box sections as I can imagine small hitchhikers making a home there!!😬😬😬😬😬

The bolts are definitely not the problem. Rather, you have to calculate how much your profiles can withstand in the areas weakened by the holes.

In 1998 when I worked in Holland and Belgium. The difference between Dutch and Belgian McDonalds was that the tomato sauce and mayo was on tap in Belgium. Small waxed paper cups I'd fill 5 red sauce and 7 mayo whilst my washing was going round in the launderette. Life on Sundays were closed pubs and wash days

Just a suggestion with the pulleys and such to lift the motors. The fiddle block with cams could go across the top on the outsides for each motor pod, that way you're pulling the rope across the top of each pod towards the middle of the boat, not down. Or, if you wanted to get fancy you could put the fiddle block on the side nearest the cockpit with the tail going to a pulley on the outside bracket across the motor pod then tie the tail of the rope back near the fiddle block in the middle. That way you're still pulling towards the middle but the cam is right by your hand in the middle and the extra rope could just fall down in the motor pod when retracted. It costs an extra pulley but makes the direction you have to pull towards the most natural, towards the middle for both motor pods. It'd be a heckuva lot easier to explain with pictures :) Love the progress, stay warm and dry!

The bolts aren't the issue. Need to weld the tubes together so they are ridged. If left only bolted together, the movement of the tube will create the failure point.

You can put the spacers on the end of a stick with masking tape to reach the holes in the middle of the bars. I used the method to get a nut 2 feet down a pole.

Experienced sailor here, your construction of your engine mounts metal cross beams appear to be too close to the main wooden cross brace beam. So when the boat flexes it appears that the steel would start gouging into the wood.

my suggestion is to not worry about changing out the bolts, just have a welder friend come by and run a small bead on each junction, it'll add to the overall strength, rigidity and peace of mind in one move.

Nothing wrong with that deck son its as good as any other ! And you will be giving your mum heart attack falling thro them planks and eating that chicken nugget from 24hrs previous :)

A trick for putting spacers down a bit of tubing is to hot glue the spacer to a length of wire or a stick once you have the bolt through it a quick twist and it should pull off

That cage is fine. Who cares about the different color planks. You accomplished a lot. Cheers.

If you have access to a welder the best option would be to drill out the holes large enough to weld in a sleeve at each hole.

Hi Mark the pulley you had in your hand and not knowing the material is Tufnell, which is not a ball race.

Quite the span for those decking boards. Hopefully you are tethered to the boat at all times while on voyages.

Awesome blooper intro!

Now that you have the engine sleds bolted together- one perfected bring dad out to weld them up….

Very nice, just doubled your square footage of workspace👌💫

Best sailing show on KZfaq, I absolutely love the down to earthiness (is that even a word?) of it, warts and all.

The brown block (pulley) is made of Tufnol, a laminated material used as the original alternative to wooden yacht blocks back in the day, but nowadays are mostly sold to owners of classic yachts since they are easier on the eye than other modern blocks. They are still made by Holland Yacht Equipment and are not cheap. They run on brass bushings and last forever, so are not to be despised provided the bushings and straps are still good.

I hope all the project people noticed the technique that Mark used to rivet the angle on the motor mounts. He drilled all the holes in the aluminum, then drilled and fastened one hole at a time in the stainless. This prevents the error of holes being slightly off when you fasten it.

Mechanical engineer here - The real battle with any design of a structural frame is fatigue and movement. Make sure your frame is rigid. You may want to make some backing plates where the frames contact the wood to spread out the loads and keep the wood from fatiguing.

I made this comment last in last weeks episode. The bolts are not the issue it’s the SHS square hollow section. They need crush tubes welded into them so that the bolts go through them and the weight isn’t just carried by the SHS wall thickness. Crush tubes can also be welded midway down the tube too. They need TIG welding.

So hilarious, that shakedown cruise of the rebuilt carburetor. Lol stand that baby up! Lol

Hi, when considering mechanical advantage for your raising of the engines/sleds you would gain a tremendous amount of efficiency with your pulley system if you were to pull up from your deck rather than down. I suggest this if it’s possible to reverse your top jamming pulley…good luck 😢

Be sure you have safety straps/cables/chains in case any bolts or bars fail while at sea and also chain your engines so they are attached to the boat and can't somehow drop into the ocean depths if something inevitably goes wrong. Also chains with locks may prevent theft😁💦

"If there are any engineers in the comments"... and boy did they deliver. Hats off to the engineers in the comments.

The M10 bolts are in shear (double shear) not tension, so the area of the bolt is the controlling factor. The sludge in your outboard fuel typically occurs from ethanol added to fuel. When it is left it separates and becomes a sludge that will block small engine carburetor jets. If you are running the engine on a regular basis the ethanol additive is not a problem, if you are going to let it stand for longer periods use pure petroleum.

Glad to see you back and hard at it. Much rather watch your progress on this boat than most of the other million dollar carbon fiber projects out there. Its coming along great. Careful about taking an unplanned swim though 😀

I wanted to tell you, those smaller engines require ethanol free petrol, ethanol is a sugar and with atmospheric salt air forms a crust in all the nooks and crannies of the fuel system. Need to flush it all or replace it and don't run ethanol ever again. It may work for a short while but will eventually crust up again and clog your high speed jet and eventually the idler jet but high speed jet is first that's why she'll run but when you throttle her she'll just go bluuuuhh

I would stick with the bolts you have, but I'd add one at the intersection of the angled piece and the first down-piece of the frame.

You can buy plastic plugs to go into the stainless profiles. Will make tge setup much vetter and will protect you from exposed edges.

Those pulley blocks look like they're made of Tufnol.

Leave the Douglas Fir it will silver naturally all by itself 👍

Well within your applied loads for that bolt hole... if you want it bullet proof, weld in a sleeve. 👣🕊👽

Please see to it that nothing can lift the deck up,😊

I suspect the real issue with stainless nuts at sea is their tendency to gall because of how brittle they are. I predict they will loosen over time then snap upon retightening. Stainless is probably best for the job but anti seize would be recommended. They won't snap at the best of times I assure you.

Not quite sure when it happened but your boat seems to have been quietly transformed from a wreck that has been refloated into a capable and appealing ocean going vessel. It's looking very good. Keep your spirits up and keep going to the end. Well Done!

I agree to what someone said below: You will need something (pulley or rod or whatever) to fix the engines in the "down" position, too.

good idea to ask for help when you need it

Nice work on the deck and i would have no problem trusting the hardware you used , plenty strong enough.

CAUTION: the cross-bracing tubes to support the pulley system and engine box supports. The ends are too close Mahi's wooden beams. Everything flexes underway, so those ends will gouge into the wooden beams like a chisel. I very much like that you're going to seal and protect your decking and other raw wood. Douglas fir is good but it's not red cedar. Cheers from Vancouver, BC

Those pulley blocks are made of Tufnol - good material ! I would not worry about the static loads on your engine mounts, but the dynamic loads once it is at sea. A heavy wave breaking thru or the boat surfing sideways to a big comber on a breach. That is where things will bend & break. That gunge in your outboard carb could be due to ethanol in your fuel. Seems to absorb water and react with Aluminium carb material to then block the carb. Causes big problems with chainsaws. Cat decks are usually slatted rather than close planked to allow wave force to burst thru the deck and dissipate rather than slam into and break. I would think about introducing gaps between those planks. Keep up the good work - you are getting there.

Id put a tubber strip between the beams and the deck, stops the deck from rubbing into the fibreglass. Also use a stick with a v notch on the end with a bit of blue tack to position the spacer. Good luck

When underway wave action will cause the engines to move about. Every SS bolt should be inside a sleeve where it goes through the box section. Without sleeves the constant flexing of the tubular frame will loosen the bolts as the tube crushes. The flexing will then translate to movement at the joint. As the joint moves the bolt will enlarge the hole weakening the tube at what is a critical stress point. The aluminium tubing is the weakest link, it will fail long before the bolts shear.

M10 is plenty! Don't worry.... think maybe more about stoping tubes from compressing. Otherwise you are good to go. Great work! 😊

The primary function of a cutting fluid is to act as a coolant, bringing down the temperature of the metal piece being worked upon and the bit. The cutting fluid not only helps provide an "excellent finish" to the product getting the cutting oil treatment, but it also provides excellent "dimensional control" and adds to the life of drill bits. Out of habit, when I pick up a drill and bit a can of cutting oil is always included. Old school ways never die.

The places where you were unable to put sleeves on bolts in tubing you could use fender washers if you think it will collapse under stress .looking forward to see the next video, thanks brother

Hello MARK, you need a mechanism to keep the engines down as well. I don’t think the way you’ve got the blocks set up is the most efficient way to pull them up. You are pulling down kneeling I don’t think that’s the most efficient place for them much better if you could stand and pull upwards Try to root the pulleys so that you can do it from standing up and think about a mechanism to hold them down, so they locked in place movement swinging up and down is not good either.

Mark, as a comparison - Tiki 38 shrouds are held by 1 shackle with a pin of 8mm diameter. These shrouds are 3000kg breaking load. The chainplate for the shroud on Tiki 38 is held by 4 x M6 machine screws. So your M10 screws for engines are more than enough,,, :)

Keep it up it's all coming together nicely

Engineer: m8 or m10 bolts are totally over rated. Fill the rectangle tubes with epoxy. That will stop them deforming under load. That’s the weak point that will give way as we all know the sea can snap boats in half. The boards are fine. Just paint them or leave them and they all will turn the same colour. You are working really hard. Much respect. You have a goal and this is the only way to get to it. You will thank yourself when you are crossing the ocean.

This is like watching a van life video only on water, just as sketchy and highly entertaining, Brilliant and loving the progression of such a amazing project. Totally Hooked

The strength of the bolts isn't a problem, but the square tube is. First drilling the holes reduces the strength of the square. Also, the bolts will squash the tube. You have to have some kind of reinforcement, either a larger, thicker washer or some kind of saddle that reinforces the tube. Don't worry about the 10mm bolts. Gary Casey, P.E.

Perhaps put a spacer between the box section to stop the section from squishing in?

Insert sheath into centre position by inserting a stick from below, rest the sheath atop the stick, lower it like an elevator, into position and get the bolt back in.

Nice to see something to stand on! Keep it coming, looking more like a boat! Cheers, Ian in Blackpool

lol, McD's is never what anyone needs!!! Health is wealth sir, guard it with your life! one love!! :)

Those decks will come up lovely chief, you've made a good job of them. You may be getting moisture in your boat tank, it binds with the ethanol and drops out the fuel which may be why you're getting the gummy build up in the carb, a fuel stabiliser could help you. But I'm no expert, it's just a theory.

10:23… I’d say, just check them and replace them with relative frequency. The issue is stainless seems as though it hardens through stress, and then can fail a bit unexpectedly. But just like anything boats… Keep an eye on them and replace them from time to time. I can’t speak on the actual loads for each bolt… But it sounds like you have quite a few of them to hold a relatively small load per each. BTW… Thanks for all the inspiration I’m in a current refit, that’s been going on for quite a while and I’m constantly running into big and little obstacles. People like you definitely help keep the inspiration going, seeing all of your ins and outs and how you handle them. Cheers and much appreciation .

Love your channel, Keep up the work. I would suggest strategically, throwing some carriage bolts into your wooden platforms to keep the screws from popping out, especially at the ends and maybe the middle of each under-cross member.

"It's a bit of a work in progress." Your motto for life. Works for me!

I work in prefab concrete. Where we use anchors to remove the concrete from the mold. M10=350kg.M12=500kg. M16=1200kg. M20=2000kg. M24= 3000kg.M30= 4000kg. That is what those anchors have been tested for. I personally think M10 is enough? But if I make or build something myself. I usually go for a bit of overkill. Greetings from Spakenburg, Netherlands.

Amazing achievement so far, crack job. The bolts.... a Lynx helicopter only has 4x M14 bolts attaching the body of the helicopter to the main rotor gearbox! So all of the forces during flight go through those bolts ...you should be fine. You do need to consider the strength and the ability of the frames and boxes to with stand the continued battering of the sea when you are sailing the open ocean,

74 yr old out board mech with advice on engine starting. If cold- try setting the throttle a bit open (watch the throttle shaft to determine and not over a 1/4 open) and no choke for one pull. Then close the choke and pull till start. Be ready to open choke immediately and be prepared to just "flash it" shut for just a moment until warm. When starting warm - leave the choke out of it, but the engine must have air to start so keep the throttle a bit open. Always carry a spare rope and wrench to remove the starter housing to reveal a way to wrap start the motor. Look inside the hood as some motors had a spare rope taped there. Your throttle may have a friction adjustment to help starting.

You did the right thing butting your deck boards up together without gaps and high above the sea. Slatted decks on Wharrams maybe good in theory for dissipating breaking seas but in the meantime, even in a fairly moderate beam sea and definitely going to weather, those gaps will allow the sea to squirt up through the deck, drenching the crew and any equipment you are trying to keep a bit dry. One thing you will need with a high flush deck though at sea is a guard wire or at least a rope around the deck. You'll feel mighty vulnerable otherwise and inclined to go about on all fours. And as you mention, slatted decks are an absolute magnet for items to fall through!

Said this in your last video.. I would weld some of the tubing across the top to replace the bolts, so that the frames effectively act like hooks over your beams. Nuts and bolts get weathered and can be a pain to service even if they're stainless steel. They could also potentially chaff in the framework under heavy seas and elongate the drilled holes..

Mark, I continue to wonder if you've thought through the forces that need to keep the engines down, not pull them up. The sleds have a large enough surface area pointing downwards, and because you have two hulls containing water movement between them, you absolutely will get substantial vertical wave motion as water passes between. The containment will guarantee that the wave motion between the hulls will be greater than that in the surrounding seas. Yes, the boat will be moving up and down, but open sea is not a convenient flat plane. That area will lift the sleds, and in worst-case situations, permit them to broach. This will then be followed by a slamming as wave force and buoyancy disappears in a trough, which is going to be very rough on your engine mounts. Failing that, the stress on the end mounting plate to the sides will be substantial. Those have no gusseting or other strengthening. As well, the engines will act as keels, and take a lot of lateral stress, especially on a beam reach. That will produce a torsional moment along the length of the sleds. In short, you have a lot more complex forces that will exist than it seems like you're designing for. At minimum, I think you need an arm that extends from where the hoist now lifts the sleds, and that locks them into the down position. This would probably best come straight down from the beam. Since you don't have anything that, in the absence of the lifting straps, stops the sleds from dropping to vertical, and given the transitory stress on the straps and associated lifting gear, this sounds like a formula for a lost engine, significant structural damage to the steel frames, and other mayhem. As well, the sleds seem to be water containers. The weight of water in them in heavy seas will be substantial.. This will add to the problems. Not meant to be negative; I just wonder if you've thought this through. Final note: there is no way that you would weaken those beams with a few fasteners to anywhere close to the point where it could ever be an issue. If that's the whole reason for the elaborate frames and everything else, that is a shame, because I don't think you've spent your time or money well - and you've created a large number of other problems (see above)

Maybe feed the ends of your pulley ropes into a small windlass? That might make it easier to raise and lower them, and you'd be able to do both at the same time.

The deck's looking good. I'm not sure if you're already planning it, but I'd wire the pins on the shackles for the engine box lifting pulley system. Lots of vibration there for the pins to come loose.

Mark.. experienced idiot here don’t know much about the M10 bolts but I can tell you you’re awesome and dedicated keep up the great work 😂😂

Do yourself a HUGE service and round, trim, cover, or otherwise protect human tissue from ANY metal projections, even ones below deck or “ hidden”. When you’re tired and your skin is soft from moisture anything can cut, maime or kill you. Those L pieces on the engine supports can ruin your life. Great job though. I love your refit!

****WELL DONE CAPTAIN***

A tool manufacturer needs to give this man a brand deal! I do love the fact you do some things old school. Your dad is amazing!

Mark the ole girl is really coming together quite nicely. I think your M10 bolts are just fine overall and do not need changed. Your build imo is certainly robust enough to secure the small outboards that you have planned. Looks great and your Dad did an incredible job on the outboard boxes, really look like they will be with you for years to come! 😊

It's worth your while getting an adapter that gives you 1/4, 3/8 and maybe 1/2 inch drivers for driving sockets with the drill. That frame job would have come together much quicker, you just whizz up the bolts with the drill and a spanner, do them up up with the torque set just below max, then tighten with the socket wrench and the spanner.

Those darn bolts look strong enough. About the Simple Man doing the work... We all can say a lot and I see many nice things below, and that is what keeps your head in the work and the video processing. Keep it up, you are entertaining, educating and a very real young person. We need more like you in this world.

I'm not too clued up about the m10 bolts, but I can tell you that those old blocks. They look like they are made from "tufnol" and if so are VERY strong and durable. I have some original tufnol blocks on my boat from the 1980's and still working great today!

Your steel square tube is going to fail before your bolts.

That’s looking awesome mate. Also “Mummy why are the swans wrestling??” “They’re not wrestling dear, ask your dad what they’re doing!!”

It is looking good. Regarding your engine sleds, make sure you properly lock all these nuts and bolts. You don't want the engine vibrations to loosem them.

M10 is perfect for that job. Also, the crush tubes you have on the inside of the box section is a good move. I think the setup and load bearing points are more than adequate. Also, see if someone nearby has an ultrasonic cleaner. Best way to clean a carburetor. Makes them like new.

Oh also are you planning on using two small winches for the engines, pulling them up by hand looks like a potential nightmare.

If your concerned and need to put your mind at rest, bang in some 10.9' s or 12.9' s the weakest point will then be the box section. You can always buy a metal strip to run parallel to the box and bolt it to the side. Like a big washer running the length. Perhaps think of the engine box back movement when the waves hit, maybe some car boot opening cylinders(marine equivalent)to dampen the impact and relive stress on all of the joints.

Well done Mark! You've come on in leaps and bounds in the last few months! Only just noticed: 104K subs! Super well done! 250k soon...

Maybe think about a couple of basically just sticks or rods that you can slide a bolt thru when your engines are all the way up and that would take all the stress off your undersized lifting tackle.