New Flowmaster Twin 920 offshore cat

[hannhann00]

Hi all, (posted this on another forum but didn't get any hits so hope here may be a bit better for this subject)


I'm completely new to the boating world and to learn the hobby i recently found a Flowmaster twin offshore cat...

From reading online reviews this model seemed to have pretty good reviews and most comments i saw was that it was actually pretty decent for its price point (although these were all from some years ago)... This model seemed to have been out of production for some time but it looks like there was production runs with different spec as most online websites say it comes with 60A ESCs whereas mine is fitted with 2x 80A Skywalker ESC to the same 2860 3300 KV motors...

I wanted to ask regarding upgrading this boat in a few stages (so i can decide to what level it makes sense to spend money on a china boat like this). I'd like to use the same hardware and running gear and not change everything (perhaps can update the flex shafts if it's recommended provided they're drop-in replacements). Please give input and any tips on the following staged upgrade options I'm considering:

1) props upgrade only
- the stock plastic props are notorious for breaking. Assuming i were to keep the stock motors and ESCs (80A 2860 3300KV) what would be the best prop options for max speed (any idea on what sort of speeds could i expect)?

*ideally any product suggestions i can buy from OSE would be great to support the forum if anyone knows particular suggestions for parts (i'm thinking props, flexshafts, couplers from OSE would be good if anyone has tips from here (or happy to look elsewhere if not available here).


2) ESC + props upgrade
- if i wanted to upgrade the ESCs to something like a 120AMP, what would be the best motor (budget-friendly options as i don't want to sink loads into this boat)?
- With 120amp ESCs would i still use the same upgraded props as option 1 or go larger (and to what size)?
- With a 120amp ESC could i run 4S or would this need a motor upgrade?
- Is it worth upgrading ESCs to 120amp with the stock motors (what benefit will i see)?
- Would any of the stage 2 upgrades require stronger flexshafts (and if so what spec)?


3) motors + ESC + props upgrade
- If i got the 120AMP ESCs what would be the fastest (but again budget-friendly) motors i can install that work with the existing mounts and set-up? I assume a ESC + motor upgrade would then mean 4S is possible and again bigger props? If i modded to this level would i need to think about strengthening the hull with more fiberglass/ epoxy inside the hull?

4) would 180amp esc be overkill for such a boat?

Frankly speaking, i'd prob only go down the motor and ESC upgrade path if i found some good used gear (i.e. someone upgrading their Probat 36 or Zonda and looking to clear their old gear). Anyone have some gear they want to sell me that would suit?


Painting tips : I'd potentially like to repaint this hull but would only be using spray cans - is the process: sand back current paint, primer, spray job (can i used tamiya TS paints or is there anything better) and then how would i get a nice high gloss finish like the current gel coat - would tamiya spray clear achieve this followed by some light sanding then buff & polishing?


here is a link to the boat but as mentioned mine has the 80amp Skywalker ESCs.
https://hobbyking.com/en_us/hobbykin...___store=en_us



I really appreciate any input!!! Thanks )

[srislash]

Very nice. I like the look.

[1coopgt]

Nice looking boat . The ESC's and Motors from the Zelos 36 Twin would probably really perk the boat right up running on 6s. Watched a vid on Youtube and it looks like it handles really well and the speed isn't to bad.

[hannhann00]

thanks guys,,,, yeah i kinda surprised when it arrived as it looks decently put together (but then again as a noob - what do i know abt this). I noticed on the backing plate which supports the strut drives the plate is held in by glue/ epoxy (?) but not screwed in with nuts on the back of the screws... Should i add some nuts to these screws (would this crack weaken the seal created by the way it's currently held in place (pic attached)

Also if anyone has any input on the original questions in post #1 it would be much appreciated.

[785boats]

Here's a bit of a thread from back in 2015 when they first came out. It may answer some of your questions.

https://www.rcgroups.com/forums/show...Twin-Catamaran

[hannhann00]

this is a great find.. Thanks... And if anyone has updated learnings since 2015 pls feel free to chime in.

[NativePaul]

We race Mono1 and Hydro1 with 2860 motors with very similar KVs to that on 3s with CNC low blade area 1.4 pitch 36mm props Tenshock are the best reasonably priced ones, followed by TP. Generally we use 90A or 100A ESCs but as you have 2 motors helping eachother out, I think you would likely be fine with the same props on your 80A ESCs.

There is not much to be gained from loading up a 2860 with that KV much past that, maybe gain 5mph and lose half your run time. Not worth upgrading the ESCs for IMO.

If you put bigger ESCs in you could run 4s and see a worthwhile speed increase on those motors, but it would be SAWs only setup, with reduced reliability and good only for only a couple of passes per run, so have a think about whether that is a compromise you are willing to make, before buying new ESCs and batteries.

Personally I don't like the layout or the reputation of the well known 180A ESC, but I don't believe it is overkill per say. Except for my SAW boats that come with a risk assumed, I always pick an ESC rated for at least double the average current that I will be pulling, to keep temps down and reliability and efficiency up.

I don't know that boat so cant say for sure that they wont fit, but the zelos and proboat 36 run bigger diameter motors with different mounting hole spacing and shaft diameter to a 2860, so you will for sure need new couplings to fit them, and I expect that you would new motor mounts too, assuming that you need new mounts you will need to replace the stuffing tubes to align with the mounts, and you should probably upsize the flex shafts while you are at it to cope with the extra torque.

What is the hull made from? Tamiya TS paints are formulated for styrene, so if it is Plastic then they may be an OK choice, but I don't know anyone that has tried it. If it is a glass hull then definitely not.

Almost everyone I know uses car spray cans from the local motor parts shop, and those that don't use 2k car paints through a gun.

[hannhann00]

We race Mono1 and Hydro1 with 2860 motors with very similar KVs to that on 3s with CNC low blade area 1.4 pitch 36mm props Tenshock are the best reasonably priced ones, followed by TP. Generally we use 90A or 100A ESCs but as you have 2 motors helping eachother out, I think you would likely be fine with the same props on your 80A ESCs.

There is not much to be gained from loading up a 2860 with that KV much past that, maybe gain 5mph and lose half your run time. Not worth upgrading the ESCs for IMO.

If you put bigger ESCs in you could run 4s and see a worthwhile speed increase on those motors, but it would be SAWs only setup, with reduced reliability and good only for only a couple of passes per run, so have a think about whether that is a compromise you are willing to make, before buying new ESCs and batteries.

Personally I don't like the layout or the reputation of the well known 180A ESC, but I don't believe it is overkill per say. Except for my SAW boats that come with a risk assumed, I always pick an ESC rated for at least double the average current that I will be pulling, to keep temps down and reliability and efficiency up.

I don't know that boat so cant say for sure that they wont fit, but the zelos and proboat 36 run bigger diameter motors with different mounting hole spacing and shaft diameter to a 2860, so you will for sure need new couplings to fit them, and I expect that you would new motor mounts too, assuming that you need new mounts you will need to replace the stuffing tubes to align with the mounts, and you should probably upsize the flex shafts while you are at it to cope with the extra torque.

What is the hull made from? Tamiya TS paints are formulated for styrene, so if it is Plastic then they may be an OK choice, but I don't know anyone that has tried it. If it is a glass hull then definitely not.

Almost everyone I know uses car spray cans from the local motor parts shop, and those that don't use 2k car paints through a gun.

Thank-you bro this is really good input....

Noob question - as i already have 4x identical RC car batteries stick packs (2s/ 7.4v/ 4800mah/ 80c with bullet type connector holes in them) if i upgraded the ESCs would it make sense to use these to do 4s per motor (i've not heard of rc car style stick packs being used in boats)? This would save me buying new lipos solely for the boat. What ESC and amps would handle this application well (i.e. 120amp)?


Noted on the paint (the boat is fibreglass) - and even easier in that case. So is the correct steps then:
- sand back current paint job
- use primer base coat (normal automotive spray can)
- spray design (normal automotive spray cans)
- add clear coat/ top coat lacquer (normal automotive spray can)
- anything i'm missing?

Thanks again!

[NativePaul]

I have used car packs in boats, and while not ideal (if they are decent ones) they should be able to deliver what a 2860 asks of them.

I don't recommend running 4s, it can be done and I have done it, but if you want a reliable setup with any runtime it is not for you. If you do go for it, keep your runs to 2 passes, dont be temped to do more, and know that you are throwing the dice with each run.

You will want a 150A ESC minimum for 4s, Personally I used a Suppo 200A.

If you want a really good finish your missing a bunch of sanding:
-sand off ALL of the current paint job, you don't know what it was painted with so that is the only way to be sure you wont get a paint reaction, sand it to a 400 finish.
- use primer base coat (normal automotive spray can)
-sand primer flat, to a 600 finish
- spray design (normal automotive spray cans). paint only bonds to fresh paint, spray your coats about 10-15 mins apart to get a chemical bond, if you need to mask up for another colour you will have to let the paint fully cure, and the next coat wont get a chemical bond so you will have to sand it to 800 to get mechanical adhesion.
-sand base coats (if using pearlescents or high shine metallics, that will effect the final finish, so lay down most of your coats of the pearlescent, sand it flat with 800, then give it a final coat)
- add clear coat/ top coat lacquer (normal automotive spray can)
-wait a week
-sand flat from 1500-3000, then polish

[hannhann00]

Thanks so much! Really appreciate your time to reply with such good input. Stay well my friend:)

[hannhann00]

Btw - since I dont have any lipos for the boat yet - Im considering getting some 150amp escs and then buying and running 4s instead of 90amp on 3s - with a better 38 or 41mm 3 blade prop - i understand its more strain on the gear but I can keep it to short speed runs.

The esc im thinking abt is they Flycolor 150A boat ESC 2-6s waterproof for RC boats with water cooling system - they are cheap at sub$45.

So with the updated escs + the price diff in buying 4s vs 3s batteries it?s about a $150 upgrade if I ditch the 80amps from the get go.

Any idea on the sort of speed increase I can expect doing this and any feedback on these China esc that i mentioned?

[hannhann00]

Hello, slight bump to ask what sort of speed increase I may aim for if I go ahead and do the above $150 upgrade (switching to 150amp escs and running 4S/ 3 blade 38-41 props)?

Prop wise other flowmaster threads commonly mention 38mm 1.8p 3 blade hitting 50-52mph on 3S with 60amp esc (I think 55mph with 120amp) with no heat issues, so I?m thinking since I?d run 150amp/ 4S and a 40mm 1.8 3 blade m - the goal to hit 60mph+ (short speed runs not long driving sessions). Does that make sense?

Thx

[Old School]

My son has a single motor Flowmaster which in stock state was pathetic. The stock ESC lasted barely one run and the boat could hardly raise a ripple in a pond. He did a carbon fibre inlay and fitted a 120 amp quality ESC running 6s, still with the stock motor running I believe a very sharp (I have the injuries) 42 mm 1.6 prop. I was very surprised that such a small motor had such performance. From memory GPS tracking showed speeds around 100 klm/hour. A downside was the puny 3mm drive which sheared almost immediately. I replaced the drive shaft with a 4mm unit and replaced the strut inserts with a home made rotating bushing. It is now a very nice boat although the clear canopy insert will not stand up to a blow over and had to be replaced with a more robust installation.

[hannhann00]

thanks old school - i'm thinking rather than getting the 3S batteries i'll go direct to 4S and the Flycolor 150A (would be cool to hear if anyone has experience with this ESC) and the prop upgrades of course... Considering doing a hull inlay from the get go also (seems potentially weak).

Lets see if i can aim for cheap 60mph

[hannhann00]

Hi,,, i still haven't got around to running this boat although it now has upgraded flexshafts and cnc props. I'm going to leave the stock 80A ESCs and as i'm buying lipos i wanted to ask:

- What is the ideal mAh for this boat? Is it a base of more mAh the better = longer run times?

- Would you suggest 3000(ish)/ 4000 or 5000 mah?

- Is there any major disadvantage to more mah?

- Is a C rating of 50C enough to get the most out of this boat or should I look for lipos with a higher C rating?


*I was planning to be running 3S, although i spoke to someone else who ran the Flowmaster boat with the same mods and they mentioned they ran fine on 4S. Thoughts?