Bombard Aerotec ready for the maiden voyage (b@stard son of a Y Class) - Page 3

Fenlander · 09 July 2015, 15:35

I like that French blog in the first link. Particularly the images showing the idea of putting the inflated Aerotec onto quite a modest size car roof just with a blanket. Our holiday location is on a narrow part of a long peninsular where we'll be launching into the landward side of the sea loch. It is only a 0.5ml (1min in car, 9min walk) across this narrow part on a quiet road to reach the seaward side for some increased boating options. This would save about 20mins on the plane to go down and round...with possibly some bumpy water "round the end".

I think we'd be able to load onto the roof bars in a similar way starting by leaning on the tailgate and pop across for an alternative launch... or in fact we could possibly walk the 0.5ml with the boat on its transom wheels.

Max... · 10 July 2015, 07:57

Older links but useful info:

http://www.rib.net/forum/f50/bombard-380-a-25844.html

http://www.rib.net/forum/f50/honwave...a-32000-2.html

http://www.rib.net/forum/f50/my-new-...-up-51292.html

dave gunster · 15 July 2015, 19:53

Hi i have a 380 , its grate with a mariner 15 2 stroke , like the look of your floor. I had a fuel bladder made to go under the gap in the floor works grate , can i ask where you got it from thanks,dave g

Max... · 15 July 2015, 19:57

Hi Dave, it's a standard RNLI Seaflex 7.5 gallon bladder. There are a couple on sale on here in bits and pieces.

dave gunster · 15 July 2015, 21:17

Thanks will have a look

Max... · 20 July 2015, 08:04

Spotted this neat and easily removable simple slot on anti-splash plate on a German forum.

I registered on the forum but still cannot see the main topic on this he links but it's just a case of cutting and slotting a piece of alu angle I guess.

https://translate.google.co.uk/trans...881&edit-text=

Fenlander · 20 July 2015, 11:34

I'm getting really interested in the thought of making and trialling a splash plate... with about 60Nm of splash experience under my belt now.

I looked under the engine cowl when the family were exploring a beach mid trip yesterday and the splash is getting up through the outboard lower cowl drain holes enough to put beads of water on the plug leads and coils. This is with the maximum thickness shim (30mm or so) before the metal pad needs lifting. No misfire yet but the potential is there.

Other thing I noticed is the splash I'm referring to is when the boat seems properly trimmed to me... re people/weight distribution. Last night though daughter was cold with the headwind on the plane so got down to sit inside the bow facing the stern which made the boat feel a bit nose down to me.... however the splashing was reduced to a mini rooster tail which was missing the outboard and not splashing inside.... quite acceptable.

That long plate linked above is not quite as neat as the one pictured by chipko on post 7 here... http://www.rib.net/forum/f50/old-use...ons-68875.html but it does have the advantage of avoiding drilling yet more holes in the transom.

Another thought... and you're better than me at forum searches Max... didn't someone posts ages (years?) ago about making a piece that they cable tied to the troublesome lumpy bit of the outboard that's causing the splash... a sort of wing leading edge idea so it cut through the water better??

Max... · 20 July 2015, 11:42

Quote:

Originally Posted by Fenlander

That long plate linked above is not quite as neat as the one pictured by chipko on post 7 here... http://www.rib.net/forum/f50/old-use...ons-68875.html but it does have the advantage of avoiding drilling yet more holes in the transom.

Another thought... and you're better than me at forum searches Max... didn't someone posts ages (years?) ago about making a piece that they cable tied to the troublesome lumpy bit of the outboard that's causing the splash... a sort of wing leading edge idea so it cut through the water better??

Agreed - anything that slots on without more transom holes gets my vote. As you say the other one was neat too - the ideas could be combined I'm sure and modded to clear wheels etc. The German idea seems to imply the splashing is from the hull maybe that then hits the leg?? Not sure it comes from the leg directly so much (not dared lean over enough at high speed to really see!) and if you look at the part of the leg that sits below the anti splash plate and in the water - it is streamlined already.

Fenlander · 20 July 2015, 11:58

>>>not dared lean over enough at high speed to really see!

I started to do that yesterday to try and take a video but sense prevailed...

Max... · 20 July 2015, 16:49

Well, had a spare hour off work this afternoon and searched the garage for materials. First plan was a piece of alu angle which I cut to size but then when looking for some spare rubber sheet (from the Aerotec flooring) I found a redundant PVC hedge trimmer attachment thingy (never throw *anything* away

).

A bit of cutting and shaping later and I just need to bond the two together and work out some sort of quick release attachment method.

beerbelly · 20 July 2015, 16:56

that's what I like to see good old British ingenuity made in a shed engineering should work a treat that .I tried an aerotec for a weekend once and one of the things I wasn't keen on was the splashing over the transom

Fenlander · 21 July 2015, 00:41

I assume on our Mercury/Mariner 15 models the splash is because water is getting up to this area??

dave gunster · 21 July 2015, 07:31

I had same prob with mine ,running with mariner 15 2 st, I raised the transom 50mm and fitted some , dole fines , that fixed it the problem .

Max... · 21 July 2015, 07:36

Quote:

Originally Posted by Fenlander

I assume on our Mercury/Mariner 15 models the splash is because water is getting up to this area??

Not sure - difficult to see exactly but as posted earlier (and read this in other places) I think it's the shape of the hull that jets water up somehow, whether it hits part of the engine and up I'm not sure, I've not had it come over the transom though.

Quote:

Originally Posted by dave gunster

I had same prob with mine ,running with mariner 15 2 st, I raised the transom 50mm and fitted some , dole fines , that fixed it the problem .

Don't really want to get into raising it more as this would mean major mods and even with a 26mm shim it will ventilate sometime in very sharp turns/bigger seas.

Fenlander · 21 July 2015, 08:44

>>>I think it's the shape of the hull that jets water up somehow, whether it hits part of the engine and up I'm not sure

Yes I guess if you imagine an Aerotec towed onto the plane without an outboard there may be a slightly confused meeting of water immediately behind the keel... add in the presence of an outboard leg and unless it all coincides perfectly there's plenty to cause splashing.

Fins probably work somewhat the same as my daughter being in the bow giving a more level or bow down ride. I have a couple of sets in the garage but so far this outboard is undrilled so not keen to experiment.

Really interested to hear the results of your splash shield Max. For me that design using the transom wheel buttons would be another faff at the slip but if the principle is sound you could buy and mount a second set of buttons about at the width of the outer transom pad purely for the purpose of attaching a narrower splash bracket (like the one linked above - post 7 here... http://www.rib.net/forum/f50/old-use...ons-68875.html ) so it could stay on all the time apart from when you wanted to pack the boat away.

Max... · 21 July 2015, 08:50

I'd leave it on all the time if it works - one of the reasons I wanted to make it from PVC/rubber is it won't get in the way when folding etc or corrode and will be a bit more sacrificial if something goes wrong!

Only issue is how to affix it - pic below shows the L shape PVC bit (without the rubber flap bonded still). It needs to sit here to clear the clips for the wheels.

I reckon either two brackets fixed using the two lower ply engine plate screws, Sikaflexing it or two small screws with spreader washers into the transom.

Sikaflex is favourite (neatest, no screws, reversible) I think.

Fenlander · 21 July 2015, 09:07

Just looking about other Aerotec threads while we wait for the Scottish sun to appear... guaranteed according to BBC weather... and found this image about matting. What interested me was the very pro job Big Al C has done to raise his transom...

http://www.rib.net/forum/attachment....4&d=1401830893

Can't find if he discussed doing this and what height it is??

Max... · 21 July 2015, 09:30

Check these:

http://www.rib.net/forum/f50/transom...res-61289.html

http://www.rib.net/forum/f36/matchin...som-55140.html

I'm no fan of non-reversible mods TBH and think raising things this much may be a step too far potentially in terms of loading.

Fenlander · 21 July 2015, 10:49

Two good threads there... the Locozodiac ones got me thinking more about what exactly makes the splash rise up to the engine cowl and perhaps over the transom.

So with very limited holiday facilities I've had the gaffer tape out and crudely "filled" in the gap that could just cause splashing if water is being directed above the upper deflection plate into this area.

Results later.

Fenlander · 21 July 2015, 16:25

And the result is... 5-10% improvement if that. But I did take my life in my hands and look over the transom at speed... plus do a short bit of video.

It seems the initial source of the splash is the meeting of water from the floor either side of the keel as it joins in the void make by the keel. So the cav plate is often running in confused water unlike a normal flat floor SIB.

Don't think I can upload the video until I get home to the PC at the end of the week.

Back to the bracket mod then.