Trim Tab designs
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
Trim Tab designs
Hi Guys
Thought I'd make this post to attract attention as I've been talking to RBT about it on another thread, so I appologise if it annoys anyone by doing this.
I've bought an inflatable and put a Seagull on it. By what the guidelines of the boat say, and the videos on youtube show, with any amount of speed the bow will lift like a sail, which could be dangerous. An idea from H.A. on another thread has brought the idea of fitting trim tabs. Sounds good.
Now at the moment I have a purpose built (heavy plastic) transom board for mounting the engine, but this is no problem as I intend replacing it with a wooden one. By doing this I can extend it to accommodate the design of fitting trim tabs to it. RBT suggests a rope pulley system which I will run with since he's smarter than me. Would anyone else like to come up with their ideas of a design? There's a prize for the best, I'll promise not to bother the winner ever again with my questions.
Thanks
Gerard
Thought I'd make this post to attract attention as I've been talking to RBT about it on another thread, so I appologise if it annoys anyone by doing this.
I've bought an inflatable and put a Seagull on it. By what the guidelines of the boat say, and the videos on youtube show, with any amount of speed the bow will lift like a sail, which could be dangerous. An idea from H.A. on another thread has brought the idea of fitting trim tabs. Sounds good.
Now at the moment I have a purpose built (heavy plastic) transom board for mounting the engine, but this is no problem as I intend replacing it with a wooden one. By doing this I can extend it to accommodate the design of fitting trim tabs to it. RBT suggests a rope pulley system which I will run with since he's smarter than me. Would anyone else like to come up with their ideas of a design? There's a prize for the best, I'll promise not to bother the winner ever again with my questions.
Thanks
Gerard
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Re: Trim Tab designs
If I were you I would ditch the rubber boat, go out and buy a few sheet of ply and make a wooden one.
There are loads of plans available on the net, plus loads of information on how to do it.
If you have any DIY skills then making a Stitch and Glue boat should not prove too difficult.
http://www.duckworksmagazine.com/
Duckworks is a good place to start.
H-A
There are loads of plans available on the net, plus loads of information on how to do it.
If you have any DIY skills then making a Stitch and Glue boat should not prove too difficult.
http://www.duckworksmagazine.com/
Duckworks is a good place to start.
H-A
Last edited by Horsley-Anarak on Sat May 08, 2010 7:42 am, edited 1 time in total.
Re: Trim Tab designs
Yeah, probably right but there's the trailer then the towbar, all of which I don't have hence the rubber boat. I actually hope to do as you suggest this winter as a project, until then all I want is to potter about (not at high speed) and enjoy my wee Seagull, and the relaxation on the water, safely.
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Re: Trim Tab designs
No problem and no tabs needed. just ajust your trim with crew weight. if on your own, use a tiller extension and sit amidships. or you could just carry a full 25L water can in the bow. Transom-less inflatable dingies are a little bit less stable, but our Avon 310 (3.1M with a transom) is fine in up to Beufort force 7 in reasonably sheltered water (less that 2 miles fetch open to windward) Get out on the water, be sensible and keep your weight low in the boat and get a feel for the handling. DONT bother with trim tabs. There is such a thing as a doel fin that atttaches to the cavitaqtion plate of a regular outboard but its not needed for an outboard like a seagull that will never get you planing (unless 'blueprinted' for racing)!
Re: Trim Tab designs
You can always chock the top rear part of your transom bracket so the motor leg is leaning towards the boat. Will force the bow down but agree weight distribution is the key. How thick is the plastic on those inflatables? Hate to rub up against some oysters. Scary. Good luck with it.
Re: Trim Tab designs
Thanks guys, my mentor (RBT) has given me these instructions regarding tiller extension and weight forward etc. The trim tabs were just a thought. I won't be doing much speed, it's more of a walk on the water rather than a race I intend. Maybe in future years I'll have a more stable craft so that I can enjoy a bit of speed, something like the craft Charles was in, on his trip down under, now that looks fun. H.A. has given me good thoughts for a winter project, a build of my own. Until these dreams become reallity, it's me, my rubber toy (note the word TOY not doll!) and my old faithful FPC.
Re: Trim Tab designs
Any good ideas of a good skiff to build, or the likes?
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Re: Trim Tab designs
common problem with small boats where you do not have enough power to get onto the plane ....you are unable to get over the hump as the technical guys say ..so you stay pointing skywards ..the solution used here in Aus is a fin on the outboard ..for underpowered craft like yours you will need the bigger size ie for 50 hp + or make your own out of aluminium sheet and bend rear down and front up. cut a 10 inch square of ali from corner to corner and start with that ..of course the real thing wont fit straight on as the cavitation plate on a seagull is too thick ..And of course you need the motor tucked under as much as you can ...
cost about 15 -25 quid for the real thing
personally I find duckworks very old fashioned ..
try Hannu's boatyard ( googe it ) or http://www.glen-l.com as well as http://www.epoxy-resins.co.uk if he got his website back together...and look at my post about boat design software a little lower down ....
cost about 15 -25 quid for the real thing
personally I find duckworks very old fashioned ..
try Hannu's boatyard ( googe it ) or http://www.glen-l.com as well as http://www.epoxy-resins.co.uk if he got his website back together...and look at my post about boat design software a little lower down ....
Re: Trim Tab designs
I always thought seagulls were only meant for displacement hulls, a trim tab would be a waste of time and effort as it is very unlikely that a classic seagull would get a boat on the plane. displacement hull boats rely on crew and gear positioning to get the best trim.
I know they are not at their best on a planing hull.
I know they are not at their best on a planing hull.
- skyetoyman
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Re: Trim Tab designs
something like a mirror dinghy will go on a roof rack. a pram dinghy with a flat front about 9ft would be similar to a 11 to 12ft sharp bow boat.
A mirror was my first fishing boat , went on top of a mini and was quite happy with a 2 hp short shaft. larger seagulls were not designed for rubber boats
A mirror was my first fishing boat , went on top of a mini and was quite happy with a 2 hp short shaft. larger seagulls were not designed for rubber boats
LLS c 1961 on a crescent 42 boat c 1980 + wspcl c 1976 + 102 SD8561 c 1944 + 102 ACR 1948
- Rob Ripley
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Re: Trim Tab designs
Small is good....[attachment=0]13042006.jpg[/attachment]
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- 13042006.jpg (72.19 KiB) Viewed 674 times
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Re: Trim Tab designs
Gerard, have you been out in your rubber boat yet?
You see, you dashed off, ill prepared, and purchased it without prior consultation.
I would have suggested the purchase of a similar sized RIB with the extended pointy side tubes. That style would have given better aft stability - the transom is set well forward.
But what's the point in criticizing you after the event? I hoped someone else would save me from doing it.
My reference to the trim tabs was purely a spurious josh, but then you went and took it seriously! And it would appear did one or two others . . .
Well, I do need some sort of entertainment . . .
We require a test report
You see, you dashed off, ill prepared, and purchased it without prior consultation.
I would have suggested the purchase of a similar sized RIB with the extended pointy side tubes. That style would have given better aft stability - the transom is set well forward.
But what's the point in criticizing you after the event? I hoped someone else would save me from doing it.
My reference to the trim tabs was purely a spurious josh, but then you went and took it seriously! And it would appear did one or two others . . .
Well, I do need some sort of entertainment . . .
We require a test report
Last edited by rosbullterier on Tue May 04, 2010 10:51 pm, edited 2 times in total.
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Re: Trim Tab designs
I got it
H-A
P.S. RBT Do they sell Doom in Essex ?
P.P.S When you post pictures as an attachment, does the aspect ratio change. Robs boat looks a bit short
H-A
P.S. RBT Do they sell Doom in Essex ?
P.P.S When you post pictures as an attachment, does the aspect ratio change. Robs boat looks a bit short
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Re: Trim Tab designs
With enormous regret I shall not be finding out. HID has pointed a few too many times the work list to be completed before age completely overtakes my frail frame.
That coupled with withdrawing circa £450 from our building funds for The Fishermans, petrol etc. Even Chuky is concerned that the odd woman he traps (or dreams about) is phased at the sight of his kitchen . . .
1. I think Betty Stoggs is better than Doom at The Ship
2. If Gerard turns up then I shall -
- in spite of putting up with my Dundee father for far too long . . .
That coupled with withdrawing circa £450 from our building funds for The Fishermans, petrol etc. Even Chuky is concerned that the odd woman he traps (or dreams about) is phased at the sight of his kitchen . . .
1. I think Betty Stoggs is better than Doom at The Ship
2. If Gerard turns up then I shall -
- in spite of putting up with my Dundee father for far too long . . .
Last edited by rosbullterier on Tue May 04, 2010 11:05 pm, edited 1 time in total.
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Re: Trim Tab designs
I think it is a short boat.
Mind - someone's taken a chainsaw to the prow . . .
Mind - someone's taken a chainsaw to the prow . . .