Waveline V floor & 25hp

[Lee1]

Still can't find a way to post pics from the iPad

So here's a link (below) to my current and finished project. . . A waveline V floor that I've refitted, painted and the engine solution I've gone with, I have some problems with finding a right outboard as the transom to waterline is 19 inches (went for a long shaft as all shorts cavitation massively) and any outboard I've tried hits the planning tabs in the section meant to prevent this! If this outboard is to long as in to much leg in the water I will have to cut the transom down to fit a short Shaft engine but would rather not do this!!!

The link is to the bushcraft forum not another boating forum. Your thoughts please chaps. . .

Waveline v floor & 25hp Link:
(The thread does go on a bit but check out the first and last few posts for the info thanks

https://www.thebushcraftforum.uk/thr...t-re-fit.6328/


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[jeffstevens763@g]

how far down is the cav plate from the keel line lee?

[Lee1]

3 inches
Boat transom top to waterline is 19 (wood is about 16 and the tabs are about 3)
engine is 22 from top of transom mount to cavitation plate.
Is using the wood block between the engine clamp and boat transom ok? If not I think the leg would clear the tabs on trim 3 or 4 pin.

[beamishken]

19" transom is long shaft I'd imagine they make them a little short (normally 20") to get the engine deeper to prevent cavitation you will probably be ok to run like that
I would make the wood block larger to support the entire clamp assembly

[jeffstevens763@g]

i agree with BK you're going to get a bit of drag at 3 " probably not noticeable but you might have to play with the trim at that depth, if it were me i would block it up making sure there's plenty of room for the trim tabs. i have mine set to level with the keel up or down an inch is acceptable in some references.

[beamishken]

I'd assumed the engine was only 1"deep as the measurement was taken from the top of the clamps not the underside?
Can you confirm Lee where you measured the engine? It should be from the underside of the clamps where it sits on the transom to the cav plate
You can install a wood packer along the top to raise it slightly but you need to be sure the clamps still have a good hold

[Lee1]

Originally Posted by beamishken

I'd assumed the engine was only 1"deep as the measurement was taken from the top of the clamps not the underside?
Can you confirm Lee where you measured the engine? It should be from the underside of the clamps where it sits on the transom to the cav plate
You can install a wood packer along the top to raise it slightly but you need to be sure the clamps still have a good hold

The 22 inch measurement of the engine is taken from the inside top of the transom clamp (not the thread screw bolts) to cavitation plate, so when the engine is mounted on the transom the cavitation plate is 3 inches lower than the 1 inch rubbing streak that's glued to the underside of centre of the V floor, I have included the centre rubbing streak in the 19 inch transom measurement which is an inch thick and runs along the centre bottom of the boat to the bow, I've had a Honda V and the planning tabs on this waveline are twice the length! These long planning tabs add a huge amount of stern buoyancy, I can stand at the transom with a 27kg engine on the transom and the water is only a centremeter or 2 over the tabs! I last tried a 18 inch shaft engine and when I sat in the centre of the boat the top of the prop would be out the water when I went over very light wash or wake and even on WOT

[beamishken]

I assume thec18"transom engine was a mariner who made some mid length engines for the rnli?
It sounds like your at the correct height to get below the tabs and allow the engine to actually turn without catching.
If it works as is then I guess it's as good as your going to get

[Lee1]

Yes it was a mariner 18 inch I guess it was a standard shaft. The cavitation plate was just level with the tabs but with the buoyancy of the tabs the the prop was out of the water over the smallest ripples

[beamishken]

18" is mid length special build for rnli short is 15" long is 20" you do get a little variation between makers but 22" seems excessively long

[Lee1]

It's defiantly 22 I looked at the Mercury model numbers and serial numbers for this engine, its a MLH model. M for manual start L for long shaft and I can't remember what the H stood for, on the website is also showed the the code for the extra long shaft as XL - 25 inches and XXL - 30 inches
Strangely it does state Long shaft as 20 inches?
Info is at the top of page

Link:

http://www.maxrules.com/models/Merc_...les/15-25.html

[Lee1]

No be honest this boat and outboard combination is becoming a pain in the @!? I'm hoping to get it out tomo and if it's not hyper planing crazy fun that goes well both can go! I don't like the V floor and I would be putting a light wood floor on top of it which is more work and total weight I'm already thinking to get it gone. And get a new excel with a short 25hp

[Lee1]

Measured again it’s 22 technically this Outboard according to the above website does not exist lol

[beamishken]

Yeh it's obviously just a manufacturing anomaly some manufacturers will be a little either way of the standard 20" long shaft but obviously this engine is significantly longer
It should be fine and while the theory is the less engine in the water the faster you go,with a sib the engine is often set low to avoid cavitation.
The drag from the soft hull will outweigh any advantage an inch or two will make on the engine height
Use it and don't worry about it

[Lee1]

That's what I'm thinking, with all the V floor rippling the prop a few inches lower won't make any difference lol

[beamishken]

Yep I'd agree with that

[Lee1]

I have mastered pic loading here's some images. . . . No more linking to other sites

Attachment 1

[warder54]

Just a quick observation. You say the floor is rippling? sounds like it may be under inflated. Check using a gauge, also a foot pump will struggle to get it up to pressure (usually 0.8 BAR) and check again after 10 minutes in the water and top up. My Honwave air-floor wasn't great until I got the pressure right using a Bravo HP pump.

[Lee1]

Originally Posted by warder54

Just a quick observation. You say the floor is rippling? sounds like it may be under inflated. Check using a gauge, also a foot pump will struggle to get it up to pressure (usually 0.8 BAR) and check again after 10 minutes in the water and top up. My Honwave air-floor wasn't great until I got the pressure right using a Bravo HP pump.

It was a round about comment my friend as even pumped fully up the inflatable floor is still not like a hull and I'm sure standing on it etc makes drag underneath.

I've still not had this set up out due to time and poor weather but still hoping I will do so soon.

[warder54]

Originally Posted by Lee1

It was a round about comment my friend as even pumped fully up the inflatable floor is still not like a hull and I'm sure standing on it etc makes drag underneath.

I've still not had this set up out due to time and poor weather but still hoping I will do so soon.

Ok, good luck when you do get out. You can turn my Honwave upside down and stand on the hull with virtually no flex.