Please advice - 25" Verado 300 on 20" transom

[MartinN]

Hi guys,

I'm in need of your expertise advice

I'm about to install a 25" Verado 300 on my 20" transom.

Original plan was to use a jack Plate to compensate for the extra 5", but I'm afraid the weight and high torque output of the Verado will stress the transom to much. Also the JP setback will need the Vrod to be mounted even higher, making it even worse.

New plan is to install a costum build vertical extension bracket which is reinforced at the top with 1/2" solid stainless steel rods going forward through the well and bolted into the bottom stringers.

What are your thoughts - will this work? Other solution are very welcome

(It's a 19" center console boat Askeladden 635 Freestyle, not a racing boat, so it's going to be purely recreational use)

[Frenchbruno]

You already gave the answer in red letters=

Original plan was to use a jack Plate to compensate for the extra 5", but I'm afraid the weight and high torque output of the Verado will stress the transom too much. Also the JP setback will need the Verado to be mounted even higher, making it even worse.

The boat builder recommended HP of this boat is 90/175, plus the fact the Verado COG is higher than a lot of other similar power engines, and then installing a 25'' on a 20 transom on a jackplate or a bracket onto this small boat will lead you to a lot of structural and handling troubles. What's about the insurance in Denmark when going to this plan?. Does this is a joke?

[MartinN]

Thanks Frenchbruno for your input, I appreciate your honesty.

Originally Posted by Frenchbruno

The boat builder recommended HP of this boat is 90/175

The boat has a recommended 230 hp max according to the VERITAS type plate in the boat, I'm aware that some websites show wrong recommendations like 90/175 hp.

I have no worries about the boat being able to handle the 300 hp if the leg was 20", nor the weight of it (being the same as a 225 hp that is within the recommended HP rating of the hull)
I have spoken to several owners who have run both the Freestyle and WA version of the hull for years with 250 hp Opti´s without even a crack in the gelcoat.

But as you mention handling could be affected by the higher center of gravity, but I have no experience in what way?

[Frenchbruno]

Hi Martin, the recommended power is not the max power as you know.
You mention 250 opti's, but comparing the 250 optimax weight to the VERADO L6 one's is a massive difference. ~235kg vs ~303kg
So the weight difference is important, plus the fact by the engine conception the COG of both engines are different, on the optimax the COG is close to the tilt bar, on the verado L6 the cog is a bit higher an positioned more to the aft.
If you use a 25 leg on a 20 transom, you should need to bolt the engine 5 inches higher to keep the ventilation plate at the same position you've on the 20 inches shaft.
doing this lead to add weight up and generate a ''mechanical moment'' which tend to reduce the stability of the boat.Have a look here for basic info=

https://www.youtube.com/watch?v=Af0OqOCWEh4

Then there is another difference using a bot on inland waters and in the rough. Some boats are designed to a certain amount of power, no really to a certain amount of punishment.
Plus the fact adding 70 kg more than optimax 250 will put the static boat COG to the aft, and the handling comparing to the opti is going to be completely different. Porpoising can occur too with the verado 300.
with the verado you also need to have a determined minimum exhaust height to the surface of water to prevent water ingestion on the engine. adding 70 kg at the far stern will put the transom more in the water comparing to the opti for example. 6.35/2.40 width for this kind of engine weight and power is not the way to go. JMHO.
NB= I've added the cog position of both engine for a better understanding of the effect on the handling.
If you need something easy to understand put a big hammer in your hand palm
a) steel in your hand palm, handle up in the air
b) handle in your hand palm, steel up in the air
c) in situation ''a'' incline the handle 30° on each side
d) in situation''b'' incline the steel 30° on each side
e) now imagine putting the handle on the tip of your finger doing the same test
the situation ''e'' is an example when the COG is more in the aft than getting the weight in the hand palm. then you can imagine the effect of weight and cog height on the transom. hope to be clear enough.

[Frenchbruno]

may be better using drawing than pdf link.

[hunton69]

I would listen to the advice given

I put twin 225 optis on a 27 foot revenger (the boat was designed to take twin 200 efi) the legs were 25 when they should of been 20's. So they modified the trsansom.

This messed the cg of the boat but it didn't matter much as the transom then failed. An expensive mistake

[MartinN]

Originally Posted by Frenchbruno

may be better using drawing than pdf link.

I really appreciate you help, you have put my project in a whole new perspective for me.
To bad there aren't many 20" Vrods around, but I guess I just have to look even harder.

Again thank you for sharing your knowledge