A Cat builds a cat - My First Boat Build

Although I've only been involved in FE for about 6 months, I originally got involved in RC over 35 years ago. While I've built quite a few land-based vehicles (from crawlers, to race vehicles), I've never built a boat...but, that's about to change. So as to not "break the bank", I felt it might be best to start with something on the smaller side. That way, if I royally screw up, I won't be out several hundred (or more) dollars...so, I chose the 17" Drifter Micro cat, from H&M.https://uploads.tapatalk-cdn.com/202...b8ebf6cf9a.jpghttps://uploads.tapatalk-cdn.com/202...354b31c4aa.jpghttps://uploads.tapatalk-cdn.com/202...e84128d827.jpghttps://uploads.tapatalk-cdn.com/202...fa26cb93ef.jpg
To give me a slight 'challenge', I've decided to build this as a twin (and, to be completely honest, I really don't know if building a twin vs a single will be more of a challenge, or easier).

Before I continue, let me first say, "Thank you", to those who've provided helpful information...especially Bill, aka Dr. Jet, who went "above and beyond", not only providing much-needed information, but also played the biggest part in helping me select the hull I would use, as well as knowing which struts might work best with this hull.

Since this is my first time building a boat, this thread will be quite different than the build threads I've previously done. On one hand, where land-based vehicles are concerned, I knew what I was doing...and, as such, those threads were more to show what I was doing, and to help others who might be interested in doing the same, or something similar. On the other hand, in regards to building a boat, I'll admit, I have little more than a clue. As such, I have a feeling I'll probably be asking more questions, than providing useful information. Or...to put it another way...I'll probably spend a decent amount of time posting queries, ideas, & thoughts, asking for suggestions, posting what I did, and then waiting for those with more knowledge than I have to confirm what I did was "right" and/or point out the mistakes I made (and, hopefully, provide solutions top said mistakes).

With that said...LET THE GAME BEGIN!!!
(and pray that I don't seriously screw this up)

First thing's first...in one of those above photos, you might have noticed something 'amiss' with the hull...namely, the hole in the canopy. Here's a couple more photos, showing the "problem" is greater detail:https://uploads.tapatalk-cdn.com/202...15ec3b057b.jpghttps://uploads.tapatalk-cdn.com/202...2d13010b1c.jpg
I contacted H&M (almost two weeks ago), and explained what I discovered when I opened the box the hull arrived in. The hull wasn't just well-packed, and well-protected...it was extremely well-protected. Whomever packed the hull could teach Amazon a thing, or three, about how to properly pack boxes for shipping. Unfortunately, the damage was, obviously, caused before the hull was packed. At first, they assumed this had occurred after I opened the box as but I explained (and provided photos) that this was how it was when I received it. To make this long 'damaged canopy' story short, I'll end it by saying that they have made a replacement, and I received an email from them this morning, informing me that the replacement is finished, and should ship shortly.

Another "problem" I discovered upon opening the box is that the build manual is entirely in German (something that anyone who's ordered from H&M probably knows all too well). Unfortunately, my grandmother never taught me, so my German is limited to a few words, and one sentence ("Do you speak German?"). Thankfully, there's this wonderful thing called 'Google Translate'...so, I am in the process of translating the entire 17-page build manual to English (I started it over a week ago, and I'm more than halfway finished).


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Most of what I need for this build, I've already ordered (from Steve) & received. Here's what I've acquired so far:

2x HW Seaking 60A ESCs
2x Leopard 2845-2960kV motors
2x Leopard 28x40mm water jackets
2x TFL 55MM Adjustable Strut Stinger For 4mm Shaft
2x OSE .130 Flex Cable & Teflon liner, with 4mm-to-1/8" stepdown shaft (one counter-rotating)
2x OSE Thru-Hull Water Pickup (part # 80400)
2x A580051 L380/390 Motor Mounts (designed for WL Toys A959, A969 A979, & K929 1:18 RC cars)
1x OSE Center Mount 65mm Rudder(part # 80055)
1x Du-Bro 4-40 Pull-Pull System
1x K&S #8130 7/32" (5.56mm) x .014 Brass Stuffing tubehttps://uploads.tapatalk-cdn.com/202...cd95a04521.jpg
To handle steering duties, I've ordered an Airtronics 94647 Low Profile High Speed Metal Gear Waterproof Digital Servo (part # AIR94647), but I'm still needing to locate a servo mount. Technically, I already ordered/received one, but I'm having trouble finding it. If I can find it, great...and, if not, I'll just have to order another. Either way, I'll post photos once I have the servo & servo mount. Due to the available spacing on the transom, where the rudder mounts, I believe I'll need to mount the servo upside-down. Has anyone done this before...and, if so, has it proven to be "problematic", or "problem-free"?

Regarding the thru-hull water pickups, I can already guess what some are thinking. "There's not enough room to mount thru-hull pickups on a hull that small, especially considering you're installing twin motors.". Truth be told, I was skeptical, but I decided to order them anyway. My thought was, "if they'll fit, fantastic...and, if not, I'll hold onto them for some future project, and order a couple transom pickups for this one." Since receiving them, along with the motors & motor mounts, I did a quick test-fit, and I'm fairly confident I shouldn't have any problem. If there's anyone who knows otherwise, I'm interested in hearing.

I'm also considering installing a drain plug along the transom, along the left (or right) side. Some of my boats have factory-installed plugs close to the bottom, while others are close to the deck. Is one location typically considered "better" than the other? Which would be "better" in a cat? Speaking of 'water', along with the (temporarily?) missing servo mount, I'm also missing the water outlets, so I might need to order those again, as well.

Finally, between yesterday, and this morning, I've gotten more of the build manual translated, and should have it finished by the end of this holiday weekend That's it, for now. It'll probably be at least another 1-2 weeks before I start "drilling holes" in my hull...partly due to work schedule, partly due to work needing to be done on other boats, and partly due to my wanting to wait to see what others say.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

In the RC Groups certain of the thread, someone posted a reply related to the drain plug, which prompted me to bring up determining where (height-wise) to install the struts. The 'funny' thing is, I haven't even started the actual build, and I've already run into my first "problem"...it figures.

I'm trying to figure out how to best determine where (top-to-bottom, not left-to-right) to drill the holes for the stinger struts. Initially, I thought the first step would be to determine the boat's "water line at rest". To do this, I had planned on loosely placing all the internal components in their approximate place inside the hull, placing the hull in a tub of water, and marking the water line along the transom in pencil. However, I then realized I had forgotten something (possibly very important): The water line marked in such a manner wouldn't be truly accurate. Some hardware (rudder, stinger struts, flex cables, prop shafts, and props) would be missing, thus the weight at the transom would be lighter than the final weight, and thus the transom wouldn't be sitting as low as it will be once the boat is completely built. I realize I could place these items inside the hull, against the transom, and the weight, as well as the front-rear balance, would be much closer to the "final build weight"...but, even then, it still wouldn't be TRULY accurate.

So...how do I go about 'resolving' this little "problem"? Is my idea above the best way to determine the "water line at rest"? Weekend or is, or not, what IS the best way to determine where (height-wise) to place the struts? If anyone has previously built a Drifter Micro (or any other micro cat) as a twin, how did you determine at what height (from the bottom of the hill) to place the struts? Better yet, at what height did you place your struts?

I still haven't finished translating the manual...but, I do know that (so far) instructions have only been given for building a 'single'. In the first two pages, H&M does mention that the hull can be used in building a twin...but, as of yet (I'm on page 11, out of 17), no instructions have been given in regards to building the Drifter Micro as a twin.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Strut height has nothing to do with the resting water line. It is a planing hull so when traveling at speed it will lift itself out of the water. Put the hull on a flat table and a good starting point is that the bottom of the struts should be flat on the table too. When testing and tuning you may want to go up a little from there, but likely not down, so if you have a limited range of height adjustability make that as low as it will go.

I wouldn't fit the drain plug, IMO it is just another water entry point that can fail, and thus it increases the chance that you get water in your hull (and you want it dry), if it would be very useful to you, you have bigger problems elsewhere.

There is no problem mounting a servo upside down, I have never done it in a boat myself though, Personally generally mount them on their sides, with a single horn sticking up and a pushrod to connect it to the rudder. While I have used pull pull control surfaces in the tails of planes to keep the CoG forwards, I see no benefit in it for an inboard boat, again it adds an extra hole in the boat that is a potential water entry point. Almost everyone uses a single pushrod for their rudder linkage, pushrod bellows are a tried and tested way to waterproof a servo linkage. (I recommend Tenshock bellows as they are made of silicone and don't perish, whereas all the other bellows are rubber and get brittle over the years when exposed to the UV in sunlight and eventually crack up (if you have the room and access, mounting bellows internally is neater looking IMO, and largely gets over the UV problem)).

You are luck to get a manual even in German I have 2 H&M hulls and neither came with one, just a disc with a few pics of bare hulls and completed boats for reference.

Quote:

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Originally Posted by NativePaul

Strut height has nothing to do with the resting water line. It is a planing hull so when traveling at speed it will lift itself out of the water. Put the hull on a flat table and a good starting point is that the bottom of the struts should be flat on the table too. When testing and tuning you may want to go up a little from there, but likely not down, so if you have a limited range of height adjustability make that as low as it will go.

I wouldn't fit the drain plug, IMO it is just another water entry point that can fail, and thus it increases the chance that you get water in your hull (and you want it dry), if it would be very useful to you, you have bigger problems elsewhere.

There is no problem mounting a servo upside down, I have never done it in a boat myself though, Personally generally mount them on their sides, with a single horn sticking up and a pushrod to connect it to the rudder. While I have used pull pull control surfaces in the tails of planes to keep the CoG forwards, I see no benefit in it for an inboard boat, again it adds an extra hole in the boat that is a potential water entry point. Almost everyone uses a single pushrod for their rudder linkage, pushrod bellows are a tried and tested way to waterproof a servo linkage. (I recommend Tenshock bellows as they are made of silicone and don't perish, whereas all the other bellows are rubber and get brittle over the years when exposed to the UV in sunlight and eventually crack up (if you have the room and access, mounting bellows internally is neater looking IMO, and largely gets over the UV problem)).

You are luck to get a manual even in German I have 2 H&M hulls and neither came with one, just a disc with a few pics of bare hulls and completed boats for reference.

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Thanks for the info...GREATLY appreciated. Starting with the boots, I'll certainly check into (and probably order) the Tenshock bellows. Are they available through a US vendor (and, if so, might you be able to provide a source, or two?)...or, are they only available directly through Tenshock (ie. overseas)? Regarding the steering, I know I could go the standard single-pushrod route, but I really want to try a "pull-pull" configuration. Besides, the center-mounted rudder I selected (recommended by Bill/Dr. Jet) & purchased is configured for this.https://uploads.tapatalk-cdn.com/202...2bd1884f73.jpgAs for the drain hole, when it comes to hulls thar can simply be held upside-down to drain the water, I completely understand, and would agree with, what you said. Unfortunately, the design of the deck, where the canopy sits down 'into' the hull, doesn't allow water to be drained so easily. Also, as much as I like your idea of installing the boots on the inside of the hull (I'm in agreement that it would give the boat a much cleaner look), as you can see by the photo below, in addition to the "upside-down water draining problem", there's also no room for the boots inside the hull, as space between the tunnel & canopy is almost non-existent between the transom & rear of the canopy.https://uploads.tapatalk-cdn.com/202...b175a48e41.jpgAs you can see, from the photo above, the deck has a considerably-deep 'lip' (almost 0.5"), which, should the boat take on water, would prevent a huge amount of the water from draining when holding the boat upside-down. This is why I considered a drain hole/plug. Of my current 7 boats, 4 came with drain holes/plugs already installed, 1 doesn't need one (the deck has a slight 'curve' towards where the canopy sits, and there's almost no 'lip' preventing water from departing the hull), 1 I dropped a hole in the deck, directly above the coupler (the hole serves as a drain, but also allows access to the coupler for maintenance), and 1 I still haven't decided where to place the drain hole (TFL Jet Boat).

Moving back up to the hole & strut mounting position, I'm attaching two photos of the stinger - one in the full h down position, one in the full-up position, both of which were taken with the lowest part of the strut perfectly flat with a "table" (actually, the shelf of my headboard).https://uploads.tapatalk-cdn.com/202...4094f9093a.jpghttps://uploads.tapatalk-cdn.com/202...1daf700405.jpgNow, to see if I'm correctly understanding what you said, I'm posting a modified version of the first photo, with a red line drawn in, which would equate to the bottom of the hull. If I'm understanding you correctly...and, PLEASE, correct me if I'm wrong...the bottom of the hull should be perfectly flush with the bottom of the strut. As such, however much higher the center of the shaft hole is above the bottom of the strut, that should be the center of the holes drilled through the transom (ie. if the center of the shaft hole in the strut is 4mm above the bottom of the strut, then the center of the holes drilled through the transom should be 4mm up from the bottom of the left/right hulls).https://uploads.tapatalk-cdn.com/202...61fb70529c.jpgFinally, regarding the build manual, I just assumed they included a manual (in German) with all hulls. Although, I can say, no disc was included. I'm actually enjoying doing the translation (even though it is time consuming). The hardest part...and what's taking the longest amount of time...involves the additional characters not found in the English alphabet. For example, the standard a, and special ?, look almost identical, replacing the intended ? with an a can change the entire word, or even the sentence. A stranger one is the s vs ?. To some, that ? might look like a capital B, but the pronunciation is actually a sharp-S. Too bad my paternal grandmother never taught me German (speaking, or reading).

Anyway, before deciding on whether, or not, to do a drain hole...and, before marking & drilling the holes for the stinger struts, I'll wait for you to confirm my understanding is correct, or to correct my misunderstanding. Thanks, again, for your input, and your assistance. By the time I get around to building a third boat, I should (hopefully) finely know what I'm doing


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Sorry panther, just read strut and made an incorrect assumption despite the text and photos above, what you have there is a stinger, which driifers from a strut in that the front of it is attached to the hull which limits adjustability.

Forget what I said earlier, with the bulkiness of a stinger you won't be able to get the prop flat on the table, the best you can do is put that red line flush with the bottom of the hull, and set the angle of the prop shaft part of the stinger so that it is parallel with the table when the boat is sitting flat on it.

At 4mm above the table it will likely be a bit higher than ideal, but as long as you are contra-rotating you shouldn't get any prop walk which is the worst handling defect brought about by a high prop.

Quote:

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Originally Posted by NativePaul

Sorry panther, just read strut and made an incorrect assumption despite the text and photos above, what you have there is a stinger, which driifers from a strut in that the front of it is attached to the hull which limits adjustability.

Forget what I said earlier, with the bulkiness of a stinger you won't be able to get the prop flat on the table, the best you can do is put that red line flush with the bottom of the hull, and set the angle of the prop shaft part of the stinger so that it is parallel with the table when the boat is sitting flat on it.

At 4mm above the table it will likely be a bit higher than ideal, but as long as you are contra-rotating you shouldn't get any prop walk which is the worst handling defect brought about by a high prop.

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Got ya...and, thanks, again. Btw, the "4mm" mentioned isn't the actual measurement, as I was just using that figure as an example. I'll have to pull them out from the box, and measure one to see what what the actual figure is (at the transom). I'm getting ready for work, but wife is still sleeping, so can't do it right now.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Hi Panther hopefully this will help a little bit here are a couple of pictures of my Zelos 36 and the Zonda. Even though they are bigger than what you are building its still the same for mounting the stingers. You want where the stinger mounts to the hull almost at the bottom of the hull.

Looks like a fun build.

Quote:

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Originally Posted by 1coopgt

Hi Panther hopefully this will help a little bit here are a couple of pictures of my Zelos 36 and the Zonda. Even though they are bigger than what you are building its still the same for mounting the stingers. You want where the stinger mounts to the hull almost at the bottom of the hull.

Looks like a fun build.

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Thanks for the photos. I have a stinger on my CD Pursuit, but that's a mono. Seeing stingers on a couple of different cats definitely helps.

Based on those photos, and the difference in hull lengths, if I mounted them on the Drifter Micro (herein referred to as 'DM') so that the bottom of the struts are approx the thickness of a credit card above the bottom of the hull, would that be a good location? Or, should they be slightly higher? (Don't think it would be possible for than to be lower, as they'd be flush with the bottom of the hull). I realize I still haven't taken (and posted) the actual measurements...which I hope to do tonight, or tomorrow.



~ More peace, love, laughter, & kindness would make the world a MUCH better place

Quote:

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Originally Posted by NativePaul

I recommend Tenshock bellows as they are made of silicone and don't perish, whereas all the other bellows are rubber and get brittle over the years when exposed to the UV in sunlight and eventually crack up (if you have the room and access, mounting bellows internally is neater looking IMO, and largely gets over the UV problem)).

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Found the Tenshock boots you mentioned, and ordered them in yellow (I haven't even thought about paint colors for the boat, and I just "randomly" decided on yellow...not sure why). If I can fit them internally, I will...but, as I previously mentioned, I'm not certain it's possible. So as to not 'waste' money, I went ahead and ordered one of their ESCs, and programming card, for a different (Tenshock-based) boat - the "Tamiya Grasshopper" mini hydro.

EDIT: I completed the German-to-English translation of the build manual. While the original was 17 pages, due to my slight reformatting of a few pages, I was able to 'condense' it down to 16 pages.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

I am intrigued by that Tamiya Grasshopper mini hydro.

Quote:

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Originally Posted by NativePaul

I am intrigued by that Tamiya Grasshopper mini hydro.

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Check you inbox.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Quote:

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Originally Posted by Panther6834

Thanks for the photos. I have a stinger on my CD Pursuit, but that's a mono. Seeing stingers on a couple of different cats definitely helps.

Based on those photos, and the difference in hull lengths, if I mounted them on the Drifter Micro (herein referred to as 'DM') so that the bottom of the struts are approx the thickness of a credit card above the bottom of the hull, would that be a good location? Or, should they be slightly higher? (Don't think it would be possible for than to be lower, as they'd be flush with the bottom of the hull). I realize I still haven't taken (and posted) the actual measurements...which I hope to do tonight, or tomorrow.



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Can you post a picture of the back side of the stinger where it mounts to the hull? Just curious as to what it looks like. What you said should be fine I would think.

Here's a couple photos of the stinger.

As you can see from the first, from the bottom of the strut's mounting bracket, to the bottom of the stinger, measures 2.9mm, while the bottom of the stinger, to the bottom of where the shaft would exit the stinger, measures 2.1mm. With the stinger in its lowest position, this places the bottom of the shaft 5mm above the bottom of the strut's mounting bracket. To note, the stinger is for a 4mm shaft.https://uploads.tapatalk-cdn.com/202...27bbea9ee7.jpgAs for the edge of the strut's mounting bracket that will be flush against the hull, the area where the stuffing enters the stinger strut's mount is 4mm above the mounting bracket. With the opening being 6mm in diameter, that places the center of the opening 7mm above the bottom of the mounting bracket. The bracket, itself, is 31mm tall, work the center of the top mounting hole being 25.75mm up from the bottom of the bracket. The left/right mounting holes are 13mm up from the bottom, and are (center-to-center) 15mm apart.https://uploads.tapatalk-cdn.com/202...0e83f7338a.jpgI hope to have more photos & measurements posted later today.

As a quick add-on, if I were to install a drain plug, the two upper circles (in the photo, below) represent my primary location choices, while the two lower circles represent my secondary location choices.https://uploads.tapatalk-cdn.com/202...d0069b030d.jpg


~ More peace, love, laughter, & kindness would make the world a MUCH better place

This first 3 photos are only to show something I discovered when I was taking the last four photos. The first two photos are, technically, the same photo, but I marked a few things on the second one (the first is a "complete" view, while the second is a "point reference" view). Anyway, when the strut's mounting area is flat against the transom, I had assumed that the entire length of the lowest part of the strut (from point #1, to point #2, as seen in the second photo) would be flat against the table (ie. the bottom of the transom). However, such doesn't appear to actually be the case. It appears that, when the mounting area is flush against the transom, point # 2 is against the table, while point #1 might actually be approx 1mm higher up.https://uploads.tapatalk-cdn.com/202...93b429cf6f.jpghttps://uploads.tapatalk-cdn.com/202...d78a298fb3.jpgI say "appears" because it is possible I wasn't holding the strut perfectly (see third photo, below). It IS still possible that points #1 & #2 are at the exact same level, and I might have just been holding the strut slightly "off". If, however, I was holding it correctly, and point #1 is 1mm higher than point #2, then this raises an "interesting" question...which I'll get to at the end of the following post.https://uploads.tapatalk-cdn.com/202...b54a9963a8.jpg


~ More peace, love, laughter, & kindness would make the world a MUCH better place

I'm not 100% certain the following measurements are 100% accurate (due to holding with one hand, and measuring with the other). Using one hand to hold the strut's mounting surface completely flat against the transom, and using the other hand to hold the digital calipers to take the measurement, while, at the same time, trying to keep the stinger as perfectly 'upright' as possible, and while trying to keep it in contact with the table, while not lifting either the hull, or the strut...this is NOT exactly easy to do. Nevertheless, I did my best, and the measurements should be fairly accurate.

These next two photos are with the stinger in the full-down position. As best I was able to determine, the prop shaft at the drive dog, is 4.2mm above the table. Remember that, even though the strut is for a 4mm shaft, I am using a stepdown 4mm to 1/8" shaft, so the distance is slightly greater than if I were using a standard 4mm shaft. If I were using a standard 4mm shaft, the measurement would be only 3.3875mm. Whether 4mm shaft, or 4nm to 1/8" stepdown shaft, the center of the shaft sits 5.7875mm above the table.https://uploads.tapatalk-cdn.com/202...3465f793b9.jpghttps://uploads.tapatalk-cdn.com/202...ebb2f76604.jpgMoving to the measurements with the stinger in the full-up position, check the below two photos. In this position, the measurement is 6.58mm with the 4mm to 1/8" stepdown shaft. With a standard 4mm shaft, the measurement would be 6.1675mm. With either shaft, the center of the shaft sits 8.1675mm above the table.https://uploads.tapatalk-cdn.com/202...9d9602f109.jpghttps://uploads.tapatalk-cdn.com/202...c2f1a81788.jpg
Getting back to that "interesting" question, if I was holding it slightly off, and points #1 & #2 are at the same level, then I'd assume that mounting the strut "the thickness of a credit card" above the bottom of the hull would still be correct. However..."interesting question" alert...if it turns out I was holding the strut correctly, and point #1 (the strut mounting bracket, as flush against the transom) is actually 1mm higher than point #2, HOW should it be mounted? I see 3 possibilities (unless anyone can point out additional possibilities):

1) Mount to the stinger strut so that point #1 is even with the bottom of the hull.
2) Mount to the stinger strut so that point #2 is even with the bottom of the hull.
3) Mount to the stinger strut so that point #1 is a "credit card" higher than the bottom of the hull. This would mean the point #2 is approx a "credit card" below the bottom of the hull,
4) Mount to the stinger strut so that point #2 is a "credit card" higher than the bottom of the hull.

Which of these 4 options would be "correct"?


~ More peace, love, laughter, & kindness would make the world a MUCH better place

I think I would not put the drain hole low. Any time the boat is stopped or moving slow it would be in the water. And if it came out it would be undesirable. I would put it on the top of the transom.

So How are you making out?

Haven't started yet...starting has been temporarily postponed. I've actually been in Las Vegas for the past 2wks, visiting family...and, while there, I was also running my Barbwire 3, SonicWake, ShockWave, and Skater X2.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

Panther6834,

I’ve been looking on the internet at all of the different drive versions for this hull and stumbled across these photos. This looks like a clean simple solution to your strut dilemma so I thought I would post these pictures here for you.
Attachment 172238Attachment 172239